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GBE H21 Timber Weatherboarding (Outline) G#10281

By 26 February 2016November 7th, 2020Code, Encyclopaedia, Files, Outline, Outlines

GBE H21 Timber Weatherboarding Outline

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GBE H21 Timber Weatherboarding Outline
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GBE H21 Timber Weatherboarding Outline
Outline:


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GBE H21 Timber Weatherboarding Outline

NB: %%% Requires formatting (indenting)

Performance requirements

  • Resist wind load and uplift
  • Resist defection and creep
  • Weatherboarding
    • Exclude wind driven rain
    • Ventilation through space behind weatherboarding
    • Drainage through space behind weatherboarding
  • Rainscreen
    • Permit limited rain passage but drain out at base
    • Pressure equalisation though open joints
    • Ventilation tough space behind rainscreen
  • Not generate wind noise or rattling
  • Fire performance
  • Fire resistance at site boundaries
  • Low spread of flame in escape routes
  • Combustibility
  • Design life & Durability
  • Meet design life
  • 30 years treated softwood
  • 40 years durable hardwood
  • Maintain good appearance
  • Fade to grey/silver
  • Avoid corrosion staining
  • Avoid rainwater splash staining/fading
  • Require redecoration at intervals
  • Maintenance
  • None
  • Frequent and predictable
  • Replacement after design life
  • Damage at low level
  • Rain splash discolouration
  • Trapped contact water damage
  • Persistent gutter overspill?
  • Security
  • Prevent removal of screen
  • Prevent entry into building
  • Flora and Fauna exclusion or inclusion
  • Exposure Conditions & Fire characteristics
  • Hazard Class:
  • Hazard class 3: Above ground, not covered
  • Timber of durability class 1 2 or 3
  • suitable without treatment
  • sapwood removed
  • Timber of durability class 4 & 5 not suitable
  • Preservative treated timber including sapwood is suitable
  • Heat treated timber suitable
  • Internal
  • Fire
  • No requirements
  • Escape route
  • Surface spread of flame BS 476:Part 7: Class 1
  • Building Regulations Approved Document B: Class 0
  • Splinter free passage or touching
  • Sawn, planed and arises removed
  • Sawn, planed arises removed and sanded
  • Sawn planed arises removed and sand blasted
  • External
  • Weather
  • Undercover
  • Not covered
  • Sheltered
  • Severe
  • Wind driven rain index
  • Humidity
  • Precipitation
  • Fire
  • No requirement
  • Boundary proximity condition (fire)
  • Surface spread of flame BS 476:Part 7: Class 1
  • Building Regulations Approved Document B: Class 0
  • Shading (Differential fading)
  • Avoid projecting eaves
  • Shading to top of cladding and soffits below fascias
  • Avoid projecting verges
  • Shading to cladding and soffit below barge board
  • Consider pre-fading boards
  • Consider coloured decorative coating
  • Long term maintenance
  • Proximity to horizontal splash surface
  • Contact (avoid always)
  • Window sills
  • Door thresholds
  • Cladding sills/flashing/drips
  • Handrails
  • Copings
  • Close (Avoid if possible)
  • Cladding sills/flashing/drips
  • Minimum 15 mm. gap and sloping down and out
  • Clearance sufficient for ventilation of batten zone
  • Insect mesh at base and top of batten zone
  • 200 splash height
  • Ground level
  • Consider planting or gravel mulch to disturb splash
  • Balconies
  • Consider open grille decking against building
  • Access walkways
  • Consider open grille decking against building
  • Flat roofs
  • Consider loose gravel solar shading
  • 200-250 mm. (avoid textured surfaces (sawn): risk of capillary attraction, provide drip profile)
  • 450 mm. (suitable for most choices of surface finish)
  • Framing:
  • Generally
  • Metal: Not in contact
  • Timber:
  • Not in contact
  • Joinery framed (in contact)
  • Mild steel frames
  • Hot dip galvanized
  • Sacrificial Zinc rich coating
  • Stainless steel frames
  • Grade: 316 Marine grade
  • Timber
  • Same species, treatments, Surface, Finish, MC,
  • Different species, treatments, surface, finish, same MC
  • Flashings:
  • Material compatible with adjacent roofing/cladding
  • Material compatible with acidic tannin
  • Coated metal:
  • Leave protective films in place
  • (not exceeding manufacturer recommendation)
  • Aluminium (high % recycled content)
  • Polyester Powder coated
  • Anodized
  • PVF2 coated
  • Steel
  • Hot dip galvanized
  • Hot dip galvanized and sacrificial zinc rich coating
  • Hot dip galvanized and Polyester powder coating
  • Hot dip galvanized and painted
  • Alternative splash zone materials (recessed)
  • Overhang cladding beyond wall
  • Concrete plinth shown
  • Concrete plinth/DPM/Protection
  • Slates placed against plinth, dry joint, soil retained
  • Paving slab turned up forming skirting, dry joint, soil retained
  • Reconstructed stone plinth units, lime mortar
  • Brick in lime mortar
  • Plastics wood substitutes
  • Durability
  • Natural durability BS EN 350 Parts 1 & 2
  • Class 1 Very Durable
  • Remove sapwood
  • European Oak (exceptional)
  • Achievable using acetylation treatment
  • Class 2 Durable
  • Remove sapwood
  • European Oak (normal)
  • Class 3 Moderately Durable
  • Remove sapwood
  • Class 4 Slightly Durable
  • Remove sapwood
  • European Redwood (Pinus sylvestris)
  • Scots Pine (Pinus sylvestris)
  • Requires preservative in cladding applications
  • Class 5 Not Durable
  • Remove sapwood
  • Requires preservative in cladding applications
  • Life Expectancy
  • Treated Softwood: 30 years
  • Durable Hardwood: 40 years
  • Maintenance Regimes (desired frequency and complexity)
  • None
  • No decoration, fade to silver (external exposed)
  • Intensive
  • Regular sanding/stripping and over coating
  • Regular staining/oiling/waxing
  • Guarantee Requirements
  • Certification
  • NHBC
  • 10 years normally
  • Zurich
  • 15 years normally
  • Other
  • BLP
  • Supplier/Installer back to back?
  • Timber sourcing certification
  • Treatment Certification
  • Strength ad suitability certification
  • PII covered engineer with reclaimed timber
  • Moisture movement
  • General:
  • not all timbers fit these groups neatly
  • frequent uptake and loss of moisture in unfinished wood can lead to surface checking (small cracks)
  • Small movement timbers: 1% for 5% change in MC
  • Medium movement timbers: 1% for 4% change in MC
  • Home grown Oak
  • Will develop small surface cracks but will not affect durability
  • European Redwood (Pinus sylvesris)
  • Heat or chemical treatment without preservatives
  • Large movement timbers: 1% for 3% change in MC
  • Avoid in cladding
  • Sustainable Certification
  • FSC
  • FSC Certified
  • FSC Chain of Custody
  • FSC Project Chain of custody
  • FSC Recycled content (applicable to panel products)
  • FSC Reclaimed (not yet formally established)
  • Non-FSC Local source, sustainable forestry
  • PEFC
  • PEFC Certified
  • PEFC Chain of Custody
  • PEFC Project Chain of custody
  • PEFC Recycled content (applicable to panel products)
  • Non-PEFC Local source
  • Timber Quality
  • Sapwood General
  • Treated sapwood is acceptable
  • Exclude sapwood if untreated
  • Durable hardwoods
  • Knots BS 1186 Part 3
  • Classes dictate size and frequency of knots
  • Class CSH
  • maximum 6 mm. diameter knots
  • Intended for small sections
  • Not appropriate for cladding
  • Class 1
  • For planed and unfinished boards
  • For prestigious buildings
  • Easily available
  • Douglas Fir
  • Western Red Cedar
  • Tropical hardwoods
  • More difficult to obtain
  • May prove expensive in otherwise low cost species
  • European redwood
  • European whitewood
  • European Larch
  • European Oak
  • Class 2
  • Increasingly accepted for cladding
  • Unfinished and transparent finishes
  • Temperate hardwoods
  • European oak
  • Class 3
  • Traditionally acceptable for cladding
  • BS EN 15146
  • Addresses knots
  • Also addresses:
  • Acceptability of end splits
  • Shakes and checks
  • Presence of resin pockets
  • Relates to each species and defines two grade
  • Grade A
  • Grade B
  • Profiles: Take care:
  • many profiles not commercially available
  • not necessarily represent good practice in design or purpose made profiles
  • BS EN 14915
  • Characteristics, evaluation of conformity and marking
  • Reaction to fire
  • Formaldehyde content
  • Pentachlorophenol content
  • Water permeability
  • Largely irrelevant to claddings with ventilated cavity
  • Thermal conductivity
  • Largely irrelevant to claddings with ventilated cavity
  • Preservative treatment
  • Manufacturing controls
  • Good practice in construction
  • Species
  • Species Applicable
  • Softwood
  • Local
  • Native
  • European Larch (Larix deciduas)
  • care with Sustainable Certification
  • Class 3 moderately durable
  • Small movement
  • Less dense, strong and knot-free
  • Also suitable for shingles and shakes
  • Spruce (European whitewood) (Picea abies)
  • Class _ durability
  • ____ movement
  • Scots Pine (European redwood) (Pinus sylvestris)
  • Class 4 Slightly durable
  • Heat or chemical treatment not preservative
  • Medium movement
  • Non-native
  • Western Red Cedar (Thuja plicata)
  • (UK grown less durable than North American class 2) (Remove sapwood)
  • Small knots common in UK grown
  • Small movement
  • BS 8417: 60 year service life
  • Resistant to preservative treatment
  • High tannin content corrosive: protect porous and steel or iron materials below
  • Soft and brittle: Avoid applications prone to mechanical damage: low level
  • Avoid unfinished where high levels of pollution present (traffic and industrial processes)
  • Also suitable for shingles and shakes
  • Douglas Fir (Pseudotsuga menziesii)
  • (UK grown less durable Class 3-4 moderately to slightly durable than North American Class 3)
  • Moisture movement: _
  • Resistant to treatment
  • Can be left unfinished to fade
  • Requires preservative treatment
  • European Larch (Larix deciduas)
  • care with Sustainable Certification
  • Class 3 moderately durable
  • Small movement
  • Also suitable for shingles and shakes
  • Scandinavia,
  • Native
  • European redwood (Pinus sylvestrius)
  • Class 4 Slightly durable
  • Heat or chemical treatment not preservative
  • Medium movement
  • European whitewood (Pinus abies)
  • Class 4 Slightly durable
  • Heat or chemical treatment not preservative
  • Medium movement
  • European Larch (Larix deciduas)
  • care with Sustainable Certification
  • Class 3 moderately durable
  • Small movement
  • Also suitable for shingles and shakes
  • Russia, Latvia
  • Native
  • European redwood (Pinus sylvestrius)
  • Class 4 Slightly durable
  • Heat or chemical treatment not preservative
  • Medium movement
  • European whitewood (Pinus abies)
  • Class 4 Slightly durable
  • Heat or chemical treatment not preservative
  • Medium movement
  • Siberia
  • Native
  • European Larch (Larix deciduas)
  • care with Sustainable Certification
  • Class 3 moderately durable
  • Small movement
  • Very slow grown
  • Dense, straight grained and less knotty
  • Also suitable for shingles and shakes
  • Alpine
  • Native
  • European Larch (Larix deciduas)
  • care with Sustainable Certification
  • Class 3 moderately durable
  • Small movement
  • Very slow grown
  • Dense, straight grained and less knotty
  • Also suitable for shingles and shakes
  • North American
  • Native
  • Californian Redwood
  • Class 2 durable
  • infrequent use in UK
  • Also suitable for shingles and shakes
  • Douglas Fir (Pseudotsuga menziesii)
  • Aka Oregon Pine, British Columbian Pine
  • Acidic with high tannin content
  • Small movement
  • Class 3 Moderately durable
  • Straight grained, robust wood
  • Can be untreated and unfinished
  • Western Red Cedar (Thuja plicata)
  • Durability Class 2) (Remove sapwood)
  • Straight grained, largely free of knots
  • Small movement
  • BS 8417: 60 year service life
  • Resistant to preservative treatment
  • High tannin content corrosive: protect porous and steel or iron materials below
  • Soft and brittle: Avoid applications prone to mechanical damage: low level
  • Avoid unfinished where high levels of pollution present (traffic and industrial processes)
  • Expensive
  • Also suitable for shingles and shakes
  • Asia/Pacific
  • Native
  • Radiata Pine
  • Class 4 slightly durable
  • requires treatment
  • Don’t know
  • Western Hemlock
  • Class 4 slightly durable,
  • requires treatment
  • Temperate
  • Southern Yellow Pine
  • Class 4 slightly durable,
  • requires treatment
  • Temperate Hardwood
  • Local
  • Native
  • English Oak (Quercus robur)
  • Shorter lengths than European
  • 2.4 m long normally
  • 150 mm. maximum width
  • Durability Class 1 Very Durable (Remove sapwood)
  • Medium movement
  • Can be used green (un-dried)
  • Soft and workable whilst green
  • Once dry becomes extremely hard and resistant to mechanical damage
  • High tannin content corrosive: protect porous and steel or iron materials below
  • Resistant to coatings
  • Can be left unfinished to fade to grey
  • FSC and PEFC
  • Also suitable for shingles and shakes
  • Welsh Oak (Quercus robur)
  • Source: Coed Cwmry, Small section?
  • As English Oak
  • Sweet Chestnut (Castanea sativa)
  • 2.4 m long normally
  • 150 mm. maximum width
  • Durability Class 1 Very Durable (Remove sapwood)
  • Small movement
  • Can be used green (un-dried)
  • Soft and workable whilst green
  • Once dry becomes extremely hard and resistant to mechanical damage
  • High tannin content corrosive: protect porous and steel or iron materials below
  • Resistant to coatings
  • Can be left unfinished to fade to grey
  • FSC by the forestry commission
  • Available in relatively small quantities
  • Also suitable for
  • shingles and shakes,
  • post and beam construction
  • Elm
  • In short supply
  • classed as 5 non durable
  • but performs better than that
  • Used in waney edge boarding
  • European
  • Oak (Quercus robur)
  • France, Germany, Eastern European
  • Longer lengths than UK Home grown
  • ___ m long normally
  • 150 mm. maximum width
  • Durability Class 1 Very Durable (Remove sapwood)
  • Medium movement
  • Can be used green (un-dried)
  • Soft and workable whilst green
  • Once dry becomes extremely hard and resistant to mechanical damage
  • High tannin content corrosive: protect porous and steel or iron materials below
  • Resistant to coatings
  • Can be left unfinished to fade to grey
  • FSC and PEFC
  • Also suitable for shingles and shakes
  • North American
  • Native
  • American White Oak (Quercus Alba)
  • Kiln dried suitable for internal use
  • Can lead to problems if used externally
  • Can lead to extensive shakes
  • PEFC
  • Tropical Hardwood
  • General Issues
  • Take particular care with Certification
  • Durability Class 1 Very durable or 2 durable
  • Dense or very dense
  • Small or medium movement
  • Some will darken upon exposure initially
  • avoid treatment: probably unnecessary
  • Suitable for use undecorated
  • Will bleach to grey after exposure for long period
  • African
  • Small amounts of certified wood
  • Far East
  • Illegal Logging rife
  • Primary species
  • Iroko
  • Endangered species
  • Plantation grown with certification available
  • Teak
  • take care with sourcing and certification
  • Central & Southern America
  • FSC Certified available
  • Seek detailed performance characteristics of subspecies
  • Seek availability information
  • Seek length and sizes information
  • Secondary species (less well known)
  • Angelim
  • Cumaru
  • Louro
  • Itauba
  • Jatoba
  • Kauri
  • Massaranduba
  • Purpleheart
  • Tatajuba
  • Options and Alternatives
  • Designer Preference
  • Species to avoid
  • Alternatives
  • Greenpeace and FoE have lists
  • Performance Specification of timber (avoiding species specification)
  • Treatment
  • General issues
  • Service life BS 8417
  • Durable species or treatment
  • Up to 60 years (normal building design life)
  • Untreated
  • Durability to match or exceed exposure class
  • Preservative pre-treated (BS 8417)
  • Chemical
  • CCA (Copper Chrome Arsenic)
  • no longer permitted
  • (in domestic applications)
  • Where children present
  • Where food growing may occur
  • No longer made?
  • Water-borne Copper-Organic
  • Up to 60 years
  • Organic-Solvent
  • Up to 60 years
  • Water-borne micro emulsions
  • Up to 60 years
  • Mineral
  • Boron Salts
  • Up to 30 year life
  • WPA Manual
  • Methods:
  • Immersion in liquid
  • Pressure and vacuum in liquid in vessel
  • Pressure and double vacuum in liquid in vessel
  • Low pressure spraying
  • Unacceptable except:
  • Local application to previously treated timber
  • after cutting planning and drilling
  • end grain sealer
  • Applicability:
  • If timber to be left unfinished:
  • Water-borne copper-organic
  • Affect moisture content of the wood
  • Greenish tinge to wood
  • Will fade over time
  • Must be fully dried before handled or used
  • If the timber to be coated or stained
  • Light organic solvent
  • Do not increase moisture content of the wood
  • Less risk of distortion of profile
  • Must be fully dried before handled or used
  • Water-borne micro-emulsions
  • Do not increase moisture content of the wood
  • Less risk of distortion of profile
  • Must be fully dried before handled or used
  • Boron salts
  • 30 year life
  • Water soluble and susceptible to leaching
  • Fire Treatment
  • Modified timber
  • Generally:
  • Allows cheaper and readily available timber of lesser durability to be used without preservatives
  • Modification is throughout the section
  • Reduces moisture absorption and moisture movement
  • Process tends to darken the wood
  • Preservative treatment only penetrates to a limited depth
  • Chemically Modified timber
  • Process
  • Impregnate wood
  • Chemical reaction with wood
  • Effect
  • Render the wood more durable
  • Improves moisture resistance
  • Improves dimensional stability
  • Improves coating performance
  • Extends coating maintenance frequency
  • Raises timber durability
  • European redwood
  • European whitewood
  • Acetylation
  • Pressure impregnate wood with acetic anhydride
  • derivative of acetic acid (Vinegar)
  • Raises pine to Durability Class 1
  • Proprietary
  • Product Reference: Accoya
  • Manufacturer: BSW timber
  • Heat treated timber
  • Process:
  • Dries the wood
  • Heats the wood
  • Reduces the natural nutritional content of wood
  • Discourages fungi and insects
  • Effect
  • Timbers suitable for hazard category 3
  • (above ground, not covered)
  • Suitable for cladding
  • 30 year life
  • Advantages
  • Throughout whole section
  • Halves the moisture movement of timber
  • Disadvantages
  • Darkens appearance
  • This should fade due to sun bleaching if unfinished
  • Makes the timber softer and more brittle
  • Similar to Western Red Cedar
  • Use adequate number of fixings
  • Loss of fastener pull out strength
  • Proprietary
  • Finland
  • Product Reference: Thermowood
  • Manufacturer: Finnforest UK Ltd.
  • Holland
  • Product Reference: ___
  • Manufacturer: ____
  • Additional opportunities
  • Similarly modified softwood battens are available
  • But they are softer and more brittle than unmodified
  • Consider unmodified softwood
  • Fire Protection
  • Fire treatment
  • Requirements
  • Limit “Unprotected cladding”
  • Within 1 m from site boundary:
  • Of greater height than __ m.
  • Building Regulations Approved Document B Class 0
  • European Class B
  • Or better
  • Applications
  • Vacuum/Pressure treatment
  • Type:
  • External exposure
  • Leach resistant
  • Humidity resistant and maintained protective coating
  • Internal exposure
  • Effectiveness
  • Natural permeability of wood
  • Sapwood easily treated
  • Heartwood can be resistant to treatment
  • Softwoods
  • European Larch quite resistant
  • Hardwoods mostly resistant to treatment
  • Manufacturers know the species and thicknesses that can be treated to Class 0/Class B
  • WPA Manual: Industrial Flame retardant for solid timber and panel products
  • Treated
  • Treated and kiln dried
  • Cavity barriers
  • Requirements
  • Building Regulations Approved Document B
  • Different in each country?
  • Smoke and flame
  • Counterproductive for ventilation and drainage cavities
  • Stop and start the cavity above and below
  • Provide drips etc. at each floor
  • Locations
  • Party walls
  • Solid 50 x 50 mm. batten can be used at party walls
  • Party floors
  • Intumescent honeycomb
  • Intumescent strip or tape
  • Intumescent paint
  • Around window openings
  • Boundaries
  • Edges at change of materials
  • Breather membranes
  • At re-entrant
  • In line
  • No need for vertical DPC
  • Turn breather membrane to close wall
  • Hold in place with batten
  • Damp proof course from cavity wall closing
  • In-line or behind a vertical DPC
  • Extend the DPC to cover joint between any framing or sheathing of the wall
  • Pre-compressed foam sealing strip
  • Instead of gunned sealant or mastic
  • Maintain good contact over uneven surfaces
  • Will continue to expand to fill any gaps
  • Even if there is shrinkage or movement at interface of wall and timber
  • Metal flashings
  • Malleable metal flashings
  • Lead
  • Avoid below Acidic timber
  • Avoid below WRC
  • Avoid below mosses and algea
  • Dressed over solid base
  • Below windows
  • Dressed back behind base of timber boarding
  • Capping
  • Not suitable as a capping or it will block ventilation of cavity
  • May be used with open joint boarding
  • Finishes
  • Patination oil on face
  • Bitumen coating on rear face against alkali materials
  • Pressed metal
  • General
  • Profiled to self support and span
  • Project from base and background
  • Materials and finishes
  • Aluminium
  • Powder coated
  • Anodized
  • Copper
  • Unfinished
  • Pre-patinated
  • Avoid below acidic timber
  • Avoid below WRC
  • Zinc
  • Unfinished
  • Recycled aluminium
  • Powder coated
  • Protective temporary peel off strip
  • Anodized
  • Protective temporary peel off strip
  • Mild steel
  • Unfinished not suitable below acidic species
  • Galvanized
  • Galvanized and powder coated
  • Pre-drill before protection
  • Protective temporary peel off strip
  • Bitumen coating
  • Bimetallic and electrolytic corrosion
  • Avoid
  • Copper below green acidic timber
  • Lead below green acidic timber WRC & Oak
  • Zinc below western red cedar (acidic)
  • Zinc below green oak (tannin)
  • Unprotected mild steel below green acidic timber
  • mixing metals on one building
  • different metals in contact
  • Consider
  • Temporary protection during tannin release
  • More base metals towards the top
  • More nobel metals towards bottom
  • Copings
  • Project over top edge of boarding
  • Particularly exposed ends of vertical boarding
  • Drip profile downstand
  • 10 mm. clearance minimum
  • Any further will not ensure clearance of the cladding below
  • Shed water away from top edge
  • Overshadowing will prevent the boarding below bleaching (if desired)
  • Window opening top flashing
  • Requires careful detailing
  • Vertical boarding
  • Flashing to extend into adjoining boards
  • Boarding to be cut back to accommodate
  • Flush boarding difficult
  • Board on board okay
  • Base of claddings
  • Sloping top surface to drain out and down
  • Projection beyond wall below
  • Steep enough that any rain splash misses bottom of boarding
  • Maintain 15 mm. gap
  • Between bottom of board and top of flashing
  • For drainage and ventilation
  • Important with vertical boarding end grain absorption
  • Prevent excessive wetting and discolouration
  • Flashing to extend back full depth of cavity
  • Dressed or pressed up, drilled and screwed to backing wall
  • Breather membrane to overlap upstand onto flashing
  • Gap between ends of boarding and other material
  • 8-10 mm. gap for ventilation
  • End grain of horizontal boarding
  • Do not fill with any sealant
  • Changes of direction, plain or angle
  • external corners
  • Strong visual impact
  • Consider detailing at openings when detailing corners
  • Horizontal boarding
  • Solid timber set flush
  • Create re-entrant corner with vertical battens
  • Stop boards 8-10 mm. short of batten face
  • Requires high quality workmanship
  • Fix solid timber to battens
  • 8-10 mm. shadow gap between boards and solid timber
  • No sealant
  • Covered corner
  • Create corner with vertical batten
  • Stop boards 8-10 mm. short of batten corner
  • Cover ends of boards with corner piece
  • Form L shaped corner piece
  • tongued and grooved together
  • 8-10 mm. anti capillary groove on two hidden faces
  • No sealant
  • Solid capped set flush
  • Create re-entrant corner with vertical battens
  • Fix solid timber corner batten to vertical battens
  • Stop boards 8-10 mm. short of vertical batten face
  • Requires high quality workmanship
  • Form L shaped corner piece
  • tongued and grooved together
  • 8-10 mm. anti capillary groove on two hidden faces
  • Cover corner batten with corner piece
  • 8-10 mm. shadow gap between boards and corner piece
  • No sealant
  • Re-entrant corner
  • Create re-entrant corner with vertical battens
  • Stop boards 8-10 mm. short of vertical batten face
  • Requires high quality workmanship
  • Cover re-entrant corner battens with two boards of different dimension,
  • First board widest
  • Second board narrower by first board width
  • one to each face
  • 8-10 mm. shadow gap between corner boards and horizontal boarding
  • No sealant
  • Mitred corners
  • Mitreing is not recommended
  • Shrinkage will leave gap for moisture retention
  • Moisture will lead to selling and moving apart
  • Open joint Rainscreen horizontal boarding
  • Mitred open joint corner
  • Maintain normal vertical joint width at corner
  • Accommodate tolerance and any variation
  • Visible fasteners will be set back from corner
  • Diagonal boarding
  • Treat similarly to horizontal boards
  • Exposing ends of boards needs accurate cutting
  • High water run off
  • 12 mm. gaps recommended
  • Seal space behind vertical gap to prevent water entry
  • Vertical boarding
  • Board on board
  • Cladding to corner
  • Outer board at corner of one elevation
  • Inner board (cut) at end of one elevation
  • internal corners
  • At openings
  • Dimensional coordination is essential for appearance sake
  • Work with board/lap/joint width
  • Position openings to coordinate with boarding
  • Avoid notches and split boards (poor appearance)
  • Consistency is important
  • Varying board widths or laps can solve dimensions but appearance may suffer
  • Ribbon windows may simplify detailing
  • Minimise cutting to minimise labour intensity (costly)
  • Minimise cutting to minimise waste (costly)
  • 3D consideration of flashings, DPC and sills essential
  • Maintain integrity of defence against water entry
  • Maintain pattern of visible fasteners around openings
  • Eaves
  • General
  • The greater the overhang the more pronounced the shading and likelihood of differential bleaching of unfinished surfaces
  • Projecting eaves
  • Horizontal soffit
  • Sloping soffit
  • Fascia
  • Verges
  • Bargeboards
  • Fascia
  • Soffit
  • Parapet
  • General
  • No overhang avoids shading and ensures consistent weathering
  • Capping with lead will seal ventilation zone
  • Capping with self supporting metal maintains ventilation
  • See
  • Moisture Content
  • Green
  • Seasoned
  • Kiln dried
  • Surface Texture
  • Sawn
  • risks of splinters
  • Capillary attraction of splash water up surface
  • More surface coating required for coverage
  • Better protection with more coating
  • Fine sawn
  • Suitable for stains
  • Sawn Planed
  • Sawn Planed Arises eased
  • Removes risk of splinters during handling
  • Sawn Planed Sanded
  • Sawn Planed Sand blasted
  • Decoration
  • Types
  • General
  • No decoration will lead to:
  • timbers bleaching to grey/silver
  • some friability of the surface
  • particularly with softwood
  • Decoration should be applied as early as possible
  • Maximise the performance of the coating
  • Uncoloured decoration is poor UV protection
  • generally not suitable externally
  • pigments are necessary
  • Opaque coatings
  • Offer best protection
  • Translucency
  • Can permit the figure, texture, grain and colour show through
  • Colours:
  • Can simulate natural colours
  • Can contrast with manmade colours
  • Dark colours offer greatest UV protection
  • Dark colours raise the temperature
  • Raised temperature will drive out moisture
  • Drying timber may suffer cracking or checking
  • Raised temperature can lead to resin exudation
  • Permeability
  • Can enhance the ability of the timber to dry out through stains and low build finishes
  • Can protect from moisture uptake
  • Film forming coatings
  • Paints and varnishes
  • Can resist moisture uptake
  • Are too brittle upon aging
  • Will crack as moisture movement occurs
  • Lets moisture in
  • Can trap moisture under surface in the wood
  • Possible degradation of the wood
  • Possible blistering, flaking and peeling of the finish
  • Should ideally be extensible:
  • To cope with moisture movement of timber
  • Micro-porous coatings
  • Are flexible enough to follow moisture movement
  • Are permeable to permit loss of moisture from under the surface
  • Apply to fine sawn surfaces for longer life than planed
  • More coating needed for sawn surfaces
  • Can help the wood retain its colour
  • Application
  • UK worst practice
  • prime timber before building in
  • Absorbent surface against permeable construction
  • Scandinavian best practice
  • full coating system on all faces
  • Compromise
  • Minimum one full topcoat on all faces
  • Consistent moisture uptake and loss possible
  • Shrinkage will not reveal uncoated surfaces
  • Location
  • Factory
  • Controlled moisture content (if timber)
  • Controlled humidity (in factory)
  • No Precipitation
  • Controlled wind movement
  • Controlled sun (exposure of wood)
  • Machine applied
  • Controlled application rates
  • Controlled drying
  • On-site
  • Uncontrolled moisture, humidity, wind, sun exposure, precipitation,
  • Unpredictable on site labour skills
  • Timber exposed to ultra violet light degraded
  • Risk of inconsistent factory undercoat and site top coats
  • Diminished life expectancy
  • On-site maintenance
  • Do not let bare timber to be exposed before maintenance
  • Poor UV affected surface will lead to poor adhesion
  • Hardwoods more difficult to gain penetration or adhesion
  • Sand down or strip all film forming coatings
  • Unfinished
  • Weather and bleach naturally in UV sunlight
  • General
  • No further maintenance
  • Long life possible
  • Sun (UV light) bleaching to grey or silver colour
  • Some will go to brown
  • Bleaching will not affect the durability of the timber
  • High levels of UV light do not reduce life expectancy
  • More movement in the surface
  • due to fluctuating moisture content
  • Some surface checking (small cracks) may occur which will open and close
  • Pollution and dirt accumulations higher on un-finished
  • Can lead to blackening of the surface
  • Low moisture movement species best
  • Partial bleaching
  • Affected by shading
  • Eaves, verges, balconies, solar shading, rainwater goods, lights, signs, sills and drips
  • Can be high contrast, unexpected and unacceptable
  • It is a design failure rather than a materials failure
  • Consider pre-bleached timbers
  • Consider different detail in sheltered no-bleach zone
  • Orientation affects rate of bleaching
  • Slow: north east, north, north west
  • Fast: south east, south, south west
  • Shading by other buildings can affect rate
  • Brake dust containing metal dust can react with tannin resulting in iron staining
  • Blackening
  • A number of causes
  • Cladding in the vicinity of trees or heavy vegetation or where there is unusually high run off of moisture
  • Exhaust fume pollution
  • Brake dust from cars and trains containing metals can react with tannin resulting in iron staining
  • Cement dust from local construction work
  • Mild steel fasteners in acidic timbers reaction blackens fastener and timber
  • Avoid all such risks
  • Cleaning fluids are available but remove the source of the problem first
  • Moisture content affecting colour or appearance
  • Shading can maintain moisture content higher that that warmed by the sun
  • Contact surfaces at base of cladding and other penetrations
  • Maintain timber in wet condition
  • Splash zones can keep moisture content high
  • Splash 200 mm. and capillary attraction up sawn surfaces a further 250 mm.
  • Eaves abutment with gables, blocked gutter overflow zone
  • Consider different fastening regime to permit easy replacement
  • Tannin
  • High tannin content acidic timbers
  • Run-off during bleaching process
  • Porous materials below cladding
  • Stone, brick, concrete, precast stone, renders
  • Staining potential
  • Avoid by design or temporary protection
  • Softwoods
  • Western Red Cedar
  • Douglas Fir
  • Hardwoods
  • European Oak
  • Finished
  • Vapour tight
  • Lacquered
  • Painted
  • Micro porous vapour permeable
  • Low build stain high solids
  • high build stain
  • Stained
  • Stain and wax (dangerous on decking)
  • Oiled
  • Waxed (dangerous on decking)
  • Limed (traditionally on oak)
  • Health issues
  • Plant based
  • Plant based solvent
  • Water based solvent
  • Mineral based
  • Synthetic
  • High VOC
  • Low VOC (more chemicals)
  • Installation appearance
  • Co-ordinated design
  • Corners
  • Changes of level
  • Parapets
  • Openings
  • Soffits
  • Junctions with other materials
  • Board layout
  • Orthogonal shapes
  • Non-orthogonal shapes
  • Curved on plan
  • Lends itself to vertical boarding
  • Board on board works well
  • T&G difficult
  • Tight radii
  • Lends itself to narrow boards
  • Battens
  • Can be made up in thin layers capable of negotiating curve
  • Successive layers can be fixed together
  • Nails
  • Screws
  • Joints must not coincide
  • Curved on section
  • Lends itself to horizontal boarding
  • Overlap and shiplap work well
  • T&G difficult
  • Shallow angles can permit capillary attraction leading to water entry
  • Tight curves open up joints to water entry into joint
  • Sustained moisture content will lead to failure
  • Curved on elevation
  • Angled facades
  • May accept vertical horizontal or sloping boarding
  • Shallow angled façade or gable
  • Cut end of vertical boards
  • Avoid tapering horizontal boards
  • Horizontal boards
  • Additional batten to support tapered ends of boards
  • Use of diagonal boards can sometimes simplify junction
  • Combinations of the above
  • Geometry may dictate board layout
  • Vertical horizontal or diagonal board layouts
  • Combination of the above
  • Surface coverage
  • Random length and joint locations
  • Controlled length and joint locations
  • Random width(s) and joint spacing
  • Controlled width(s) and joint spacing
  • Framed panels
  • Unframed panels
  • Off-site panelised prefabrication
  • Boarded
  • Vertical
  • Diagonal
  • Horizontal
  • Mixed
  • Battened
  • Louvres
  • Solar shading
  • Rainscreen
  • Tiled
  • Shingles
  • Shakes
  • Tiles (appear like ashlar stonework)
  • Boundaries
  • Profiles, overlapping, gaps, butting T&G or TG&V
  • Profiles
  • Spaced battens
  • Weathered top edge
  • Drip profile
  • Rain-screen open joint profiled edge boards
  • Anti-capillary profiles
  • Joint layout
  • Board length limitations
  • Softwood
  • Species
  • European redwood
  • European Whitewood
  • European larch
  • Douglas fir
  • Lengths
  • Up to 4.8 m.
  • Temperate Hardwood
  • Species
  • Sweet chestnut
  • 2.0 – 4.0 m.
  • Maximum: 5.0 m.
  • European Oak
  • 2.4 m. generally
  • 2.0 – 4.0 m.
  • Maximum: 5.0 m.
  • Tropical hardwoods
  • Species
  • Varies
  • 2.1 – 4.2 m.
  • Maximum: 4.8 m.
  • Width limitations
  • European Oak
  • 150 mm.
  • Spacing and size and patterns
  • Surface profiles
  • Joint patterns & batten spacing
  • Random or standardised lengths
  • Random colour mixing
  • Fixing appearance and spacing
  • Joints
  • Horizontal boarding
  • Vertical end-joints
  • Coincident with battens
  • Standard batten widths insufficient for end joints
  • Insufficient width batten
  • Insufficient edge distance on batten
  • Insufficient end distance on board
  • Consistent length boards and all occur on same batten
  • Use two battens side by side
  • Spaced to match joint between board ends
  • Timber frame background
  • Use wide batten fixed in centreline of stud
  • Panelised boarding
  • On structural grid lines
  • Lends itself to prefabrication
  • Requires coordination of openings
  • Labour intensive
  • Requires accuracy for good visual effect
  • Invites rejection by designers
  • Wasteful of timber cutting to length
  • Invisible joints
  • Random location
  • Coincident with battens
  • Length of batten nailed to side of main batten
  • To support ends of two boards
  • Length 3 x board width
  • Butt joint positions randomly staggered
  • 5 mm. gap for ventilation and drainage of end grain
  • Vertical boarding
  • Horizontal end-joints
  • Increasingly visible over time
  • Wetting and swelling of lower board end grain
  • Run-off from upper board
  • Chamfer ends of boards outwards
  • Seal top of lower board
  • Gap: 5 – 8 mm.
  • Coincident with battens
  • Standard batten widths insufficient for end joints
  • Insufficient width batten
  • Insufficient edge distance on batten
  • Insufficient end distance on board
  • Consistent length boards and all occur on same batten
  • Use two battens side by side
  • Spaced to match joint between board ends
  • Panelised boarding
  • Storey heights
  • Most species can be accommodated
  • Lends itself to prefabrication
  • Floor level joints can accommodate shrinkage, deflection, creep and structural settlement
  • May accommodate cavity barriers between floors
  • Requires coordination of openings
  • Offcuts can be used under window openings
  • Labour intensive
  • Requires accuracy for good visual effect
  • Invites rejection by designers
  • Wasteful of timber cutting to length
  • Jointing
  • Finger jointing and end dowelling
  • Will become economic
  • Will become more commonplace
  • Longer lengths overcome need for butt joints
  • Reduce off-cut waste
  • Invisible joints
  • Random location
  • Coincident with battens
  • Length of batten nailed to side of main batten
  • To support ends of two boards
  • Length 3 x board width
  • Butt joint positions randomly staggered
  • 5 – 8 mm. gap for ventilation and drainage of end grain
  • Chamfered outward and downward
  • It may be difficult to exclude all sapwood:
  • Permissible relaxations:
  • No sapwood should be visible in exposed board face
  • No sapwood should be present in board edges, lapping or jointing profile
  • No sapwood should be present in end grain
  • Sapwood which occupies less than 5 mm. width of the hidden face may be of unlimited length
  • Sapwood which occupies more than 5 mm. width of the hidden face should be less than 500 mm. long
  • Check the class specification and modify if required
  • may be difficult to identify sapwood
  • Board Orientation & Profile
  • Horizontal
  • General issues
  • Most common
  • Profiles: simple overlap, feather or square, rebated feather, shiplap
  • Square edge
  • thickness: 16-19 mm.
  • overlap 25 mm.
  • Heart side outwards
  • Feather edge
  • thickness: minimum 8 mm. to 16-19 mm.
  • overlap 25 mm.
  • thin edge at top
  • Heart side outwards
  • Rebated feather edge
  • Thickness: minimum 8 mm. to 19 mm. low edge: 10 mm.
  • Overlap 15 mm.
  • Gap: 2 mm.
  • Heart side outwards
  • Ship lap
  • Thickness: minimum 16 – 19 mm.
  • Overlap 15 mm.
  • Gap: 2 mm.
  • Heart side outwards
  • Horizontal T&G Jointed
  • tongue uppermost
  • Heart side outwards
  • Thickness: 19-22 mm.
  • Recommended board face width: 100 mm.
  • Maximum board face width: 125 mm.
  • T&G overlap 10 mm.
  • Gap: 2 mm.
  • Not V joint (used internally or vertically)
  • Better with a rebated profile
  • Open joint
  • 30 degree sloping top and bottom edges
  • Heart side outwards
  • Widening gap towards back is better
  • gap 8-15 mm.
  • thickness 16-19 mm.
  • Insect mesh behind
  • Suitable for green timber, shrinkage less obvious
  • strong shadow line
  • UV light penetration effect on breather membranes to be taken into account
  • Reduced spacing battens to reduce shrinkage movement
  • Butted boards
  • risky for capillary attraction
  • end grain water penetration
  • Diagonal (take care with profiles)
  • General issues
  • Longer span between H or V battens
  • Diagonal battens?
  • Reduce V or H batten spacing
  • Thicker board (How thick?)
  • Avoid V pattern abutments
  • Consider A pattern abutments
  • Avoid simple overlapping boards
  • Avoid open butt joints in lengths
  • Avoid butt joints use longer boards
  • Heart side outwards
  • Ship lap
  • Thickness: minimum 16 – 19 mm.
  • Overlap 15 mm.
  • Gap: 2 mm.
  • Heart side outwards
  • Diagonal T&G Jointed
  • tongue uppermost
  • Thickness: 19-22 mm.
  • Recommended board face width: 100 mm.
  • Maximum board face width: 125 mm.
  • T&G overlap 10 mm.
  • Gap: 2 mm.
  • Not V jointed (used internally or vertically)
  • Heart side outwards
  • Overlapping
  • Vertical
  • General Issues
  • Consider lengths available and horizontal joints
  • Avoid top of board below joints absorbing water
  • Consider stopping and starting at floor levels
  • Consider fire barriers at floor levels
  • Allow for creep, deflection and settlement of the structure
  • Consider a weather drip between storeys or panels
  • Consider prefabrication of panels
  • Vertical T&G Jointed
  • Recommended width: 100 mm.
  • Maximum width: 125 mm.
  • Thickness: 22 mm.
  • Shrinkage risks disengagement of T&G
  • T&G overlap 10 mm.
  • Gap: 2 mm.
  • Can use V jointed
  • Alternative: Rebated overlapping
  • Heart side outwards
  • Rebated overlapping boards
  • Maximum width: 150 x 19 mm.
  • Heart side outwards
  • Board on Board
  • Minimum 20 mm. overlap
  • With or without Capillary grooves near the outer edges of both board touching faces
  • Suited to curvilinear plan walls
  • Tolerant of dimensional variation
  • Gap created provides ventilation and drainage
  • Gap created avoids need for counter-battens
  • Wide boards on wide board
  • 150 and 150 x 16 mm.
  • Wide boards on narrow board
  • 100 on 75 x 16 mm.
  • Narrow boards on wide board
  • 75 on 100 x 16 mm.
  • Variety of board widths permits surface modelling
  • Outer board: Heart side outwards
  • Inner board: Heart side inner
  • Open joint board
  • Widening gap towards back is better
  • gap 8-15 mm.
  • thickness 16-19 mm.
  • Insect mesh behind
  • Heart side outwards
  • Suitable for green timber, shrinkage less obvious
  • strong shadow line
  • UV light penetration effect on breather membranes to be taken into account
  • Use of breathing sheathing board appropriate
  • Reduced spacing battens to reduce shrinkage movement
  • Open joint battens
  • Widening gap towards back is better
  • gap 8-15 mm.
  • Size: minimum ex 50 x 50 mm.
  • Insect mesh behind
  • Suitable for green timber, shrinkage less obvious
  • strong shadow line
  • UV light penetration effect on breather membranes to be taken into account
  • Use of breathing sheathing board appropriate
  • Reduced spacing battens to reduce shrinkage movement
  • Sloping
  • Board on Board
  • Minimum 20 mm. overlap
  • With capillary grooves near the outer edges of both board touching faces
  • Wide boards on wide board
  • 150 and 150 x 16 mm.
  • Wide boards on narrow board
  • 100 on 75 x 16 mm.
  • Narrow boards on wide board
  • 75 on 100 x 16 mm.
  • Outer board: Heart side outwards
  • Inner board: Heart side inner
  • Reduced spacing battens to reduce shrinkage movement
  • Reduced batten spacing or sloping battens
  • Fixing & Fastenings
  • Choices
  • Hardwood
  • Screws (normal practice)
  • At or close to 16% MC
  • Allow for seasonal variation in MC
  • Oversize drill holes
  • Small movement timbers: 2 mm.
  • Medium movement species: 2 mm.
  • Clearance around shank
  • Use countersunk screws
  • Use oversize screws with bigger heads
  • Maximum 150 mm. board width
  • Locate screws ¼ board width in from edges
  • Green timber
  • Allow for considerable initial shrinkage
  • Oversize drill holes
  • Green timber: 4 mm.
  • Washer needed
  • Slotted hole washers
  • Not easy to obtain
  • Require alignment to permit movement
  • Require positioning to maximise possible movement
  • Recessed holes in timber face
  • Oversized to permit movement of washer over timber in recess
  • screw heads for use with washer
  • Round head or pan head
  • Sheeting screws with built in washers
  • Rear face fixing
  • Hardwood open joint boards
  • Panelise boards with battens
  • Screws through clearance holes
  • Front face fixing
  • Hardwood boards
  • Panelise boards with battens
  • Screw through front face and pellet or plug holes
  • To treated softwood battens (normal practice)
  • To same hardwood battens
  • Expressed
  • Demountability
  • Single lap with exposed Phillips head screw
  • Square edge board, horizontal boarding
  • Feather edge board, horizontal boarding
  • Socket in timber oversized hole, washer and screw
  • open joint boarding
  • Flat head nails at surface
  • board on board
  • Hidden
  • Limited demountability
  • Hidden J profile stainless steel fixing clips
  • Fixed to vertical batten
  • Horizontal shiplap or Open joint boarding
  • With added slot in underside
  • J profile hooks into slot
  • Screw top of boards to battens through shoulder
  • Similar principle to T&G
  • Can allow for considerable shrinkage in board width
  • Easy to engage in Joint
  • Less liable to damage tongue
  • Board can be held and aligned with wide clip
  • Requires careful design for each application
  • Taking in to account:
  • Species, shrinkage, thickness, other characteristics
  • Softwood
  • Nails (normal practice)
  • To treated softwood battens (normal practice)
  • Non-demountable
  • Lost head nails
  • Horizontal boarding
  • Open joint
  • Square edge
  • Feather edge
  • Rebated feather edge
  • Shiplap
  • T&G
  • Diagonal
  • Vertical
  • Secret fix nails
  • Not recommended in T&G Joint
  • Risk of tongue splitting
  • Recommended in rebated T&G Joint
  • Nail through shoulder
  • Metals
  • Acidic species e.g. Oak, WRC, Sweet chestnut
  • Austenitic stainless steel
  • Marine Environment: (tidal estuary and sea) Grade 316
  • Otherwise Grade 304
  • Weathers down to matt grey
  • (Quercus Fencing fastenings)
  • Galvanized steel
  • Prone to damage when driving
  • Mild steel
  • Will stain timber and fastener purple-black
  • Stain not removable
  • Non acidic species
  • Avoid ferrous if uncoated softwood boarding
  • Galvanized steel
  • Prone to damage when driving
  • Protect by coating timber
  • (Quercus Fencing fastenings)
  • Brass
  • Un finished hardwood
  • Austenitic stainless steel
  • Marine Environment: (tidal estuary and sea) Grade 316
  • Otherwise grade 304
  • Weathers down to matt grey
  • Clips or washers same metal and grade
  • Coated hardwood
  • Austenitic stainless steel
  • Marine Environment: (tidal estuary and sea) Grade 316
  • Otherwise Grade 304
  • Weathers down to matt grey
  • (Quercus Fencing fastenings)
  • Galvanized steel
  • Prone to damage when driving
  • Fastener sizes: Dictated by board thickness
  • Nails
  • Nails normally driven just below the surface
  • allow for timber shrinkage
  • avoiding nail becoming proud of surface
  • Nails 20 mm. from end of board
  • Nails 15 mm. from edge of board
  • Spacing: batten spacing dictates.
  • Small head or siding nails can pull through soft WRC
  • Larger heads recommended for WRC
  • Standard round wire nails:
  • 2.5 x thickness of board
  • T&G: 19-22 mm. = 48-55 mm.
  • Other: 16-19 mm. = 40-48 mm.
  • Annular ring-shank nails
  • Improved holding power
  • 2 x thickness of board
  • T&G: 19-22 mm. = 38-44 mm.
  • Other: 16-19 mm. = 32-38 mm.
  • Pneumatically driven nails
  • D shaped heads may not be visually acceptable
  • Virtually headless pins are not recommended
  • Screws:
  • 2 x thickness of board
  • T&G: 19-22 mm. = 38-44 mm.
  • Other: 16-19 mm. = 32-38 mm.
  • Batten size, spacing and direction
  • Batten Size:
  • Minimum 2 x board thickness
  • T&G: 19-22 mm. = 38-44 mm.
  • Other: 16-19 mm. = 32-38 mm.
  • Minimum: 38 x 38 mm.
  • Batten profile:
  • Horizontal boarding vertical batten
  • Square
  • Vertical boarding horizontal batten fixed to counter-batten
  • 15 degree sloping top face to throw off water into ventilation cavity
  • Vertical board on board horizontal batten
  • 15 degree sloping top face to throw water away from sheathing and breather face
  • Metal framing and fasteners
  • Avoid different metals in direct contact if possible
  • Introduce timber battens between boards and metal framing
  • Fix boards with stainless screws to battens
  • Fix galvanised framing with galvanized or plated screws to battens
  • If unavoidable:
  • Galvanized framing and stainless steel fasteners
  • Never:
  • Stainless framing and galvanized steel fasteners
  • Avoid self drilling, self tapping, self countersinking fasteners
  • Unprotected mild steel swarf will corrode
  • Iron staining of timber and stainless steel
  • Electrolytic action between different metals
  • See Background and counter-battens
  • Insect mesh
  • Cavity behind boards can be warm and dry home to insects
  • Insects: wasps, woodlice, flies
  • Risk factors:
  • Urban v rural
  • Proximity of trees
  • Height above ground
  • Etc.
  • Guidance:
  • TRADA do not advise on need
  • Precautionary principle could apply (do it anyway)
  • Mesh over openings:
  • Bottom and top of cavity
  • Close jointed horizontal boarding
  • Fix mesh vertically to back wall of cavity
  • Fold up and attach to underside of vertical battens
  • Spanning between battens
  • Close jointed vertical boarding
  • Fix mesh vertically to back wall of cavity behind counter-battens
  • Fold up and attach to underside of horizontal battens
  • Board on board vertical cladding
  • Fix mesh to horizontal bottom battens
  • Extend out to run continuously across the inner boards
  • Sealing gaps behind the outer boards
  • Horizontal overlapping boards
  • Square and feather edge boards
  • Triangular gaps at ends of boards
  • Alternate solutions:
  • Compressible foam tape
  • Between last vertical batten and boards
  • Fabric mesh
  • Stapled to whole facade battens before boarding
  • Open jointed boarding
  • Fabric mesh
  • Excludes insects
  • Stapled to whole facade battens before boarding
  • Reduces rain penetration
  • Shades cavity from UV light
  • Restricts visibility into cavity
  • Products
  • Perforated metal sheet
  • If metal cladding is also used,
  • Obtain from installer
  • Metal
  • Acidic timber
  • Stainless steel
  • Terne coated stainless steel
  • Zinc
  • Copper
  • Perforation size: __ mm. maximum
  • Free air area: __ %
  • Fastener:
  • Screw if adequate access room
  • Same metal as perforated sheet
  • Staple if limited access
  • Same metal as perforated sheet
  • Metal mesh
  • Mesh spacing: ____
  • Hole size: ____
  • Metal
  • Acidic timber
  • Stainless steel
  • Non-acidic timber
  • Zinc coated mild steel
  • Galvanized chicken wire (small mesh)???
  • Non-ferrous metal
  • Fastener:
  • Screw with large washer if adequate access room
  • Same metal as perforated sheet
  • Staples if limited access
  • Same metal as perforated sheet
  • Fabric mesh
  • Mesh spacing: ____
  • Hole size: ____
  • Material:
  • UV Resistant plastic mesh
  • Nylon
  • _____
  • Fastener:
  • Staples:
  • Acidic timber
  • Stainless steel
  • Non-acidic timber not coated
  • Stainless steel
  • Non-acidic timber coated
  • Zinc coated steel
  • Supporting Biodiversity:
  • Occupation v Infestation
  • What is the consequential risk of occupation?
  • Can we encourage without risk?
  • Bats?
  • Bat droppings and urine on outer face of insulation
  • Suits hygroscopic insulation
  • Dense cellulose fibre
  • Bat droppings and urine on outer face of breather membrane
  • Used with open surface hydrophobic insulation
  • Moisture resistant vapour permeable membrane
  • Paper may not be suitable
  • Polymeric may be acceptable
  • Tyvek are working with BCT
  • Bat droppings and urine on outer face of breathing sheathing boards
  • Suits hygroscopic boards
  • Dense cellulose fibre and wood fibre boards
  • Entry slots
  • Higher level (base of upper floors) may be ideal
  • Roots
  • Trapped warm air is ideal for maternity roots
  • Sunny elevations
  • Ventilated spaces are ideal for winter hibernation roosts
  • Shaded elevations
  • Or should we hang bat boxes on outer face?
  • Bees and other pollinators?
  • Lone bees
  • Drill holes in perimeter battens and horizontal board ends
  • Various diameters
  • Probably not be deep enough
  • Build in bee and insect nest box in panels
  • Swarms
  • Probably discourage
  • Avoid honeycomb building inside construction
  • Encourage separate weather-boarded hive construction (mobile)
  • Or build hives on apex of roofs (not collecting honey)
  • Spiders?
  • Insect mesh will exclude some and permit others
  • But excluding insects will deny them food
  • Birds?
  • Permitted behind cladding by poor detailing or unfinished work
  • House martins
  • Fix manufactured nests to cladding below eaves
  • Other bird boxes
  • Fix to cladding out of reach of cats
  • Background
  • Solid
  • Counter battens to provide ventilation zone
  • Battens to accommodate tolerances
  • Rainscreen Insulation & DPM
  • Insulation and breather membrane or board
  • Breathing Sheathing Board
  • Airtightness layer
  • Spaced
  • External walls
  • Studs and insulation
  • Avoid if possible creates cold bridge through insulation
  • Decrement in timber: impact on infrared survey?
  • Cold bridge analysis: Psi values
  • 400 mm. thick walls
  • 400 mm. timber stud and 400 mm. insulation
  • psi negligible
  • (but metal stud would remain a big problem)
  • Studs, insulation and sheathing board
  • Sheathing board with insulating properties will reduce cold bridge effect
  • External insulation covering the studs wraps up the cold bridges
  • Dense cellulose fibre boards
  • 2 layer studs and cross battens with insulation in both layers
  • Cold bridge minimisation
  • 400 mm. thick over all
  • Psi value minimised further
  • Breather membrane
  • Essential to prevent warm air being drawn out of insulation into ventilation space and blown away
  • Breathing sheathing board
  • Essential to prevent warm air being drawn out of insulation into ventilation space and blown away
  • May be essential to hold the insulation in place
  • Can have racking strength to add to wall stability
  • Can provide additional or substantial thermal insulation for the wall
  • Breathing wall construction
  • Internal lining
  • airtightness layers
  • Studs
  • Thermal insulation: Hygroscopic with decrement property
  • Dense cellulose fibre
  • Breathing sheathing board
  • Battens
  • Weatherboarding
  • Pitched roof
  • Rafters, eaves & verge framing
  • Rafters and boarding (Scottish practice)
  • Counter-battens and battens essential
  • BRE confirmed that breathing roof construction is also possible
  • Rafters and insulation between
  • Avoid if possible creates cold bridge through insulation
  • Decrement in timber: impact on infrared survey?
  • Cold bridge analysis: Psi values
  • 400 mm. thick roof
  • 400 mm. timber rafters and 400 mm. insulation
  • psi negligible
  • (but metal rafter would remain a big problem)
  • Internal ceiling
  • Ceiling joists with thermal insulation
  • Ceiling Joist, thermal insulation and board
  • Ideally a breather membrane is used over
  • Ceiling to flat roof
  • Decrement insulation important
  • Thermal mass important
  • Ceiling to pitched roof with attic space
  • Decrement insulation important
  • Thermal mass important
  • Ceiling to pitched roof with sloping ceiling
  • Decrement insulation important
  • Thermal mass important
  • Ceiling to room in a roof
  • At eaves (beyond room)
  • Insulated
  • Decrement insulation important
  • Thermal mass
  • Below room
  • Insulated
  • Decrement less important
  • Thermal mass less important
  • Floor
  • Suspended ground floor
  • Suspended upper floor
  • Suspended floor over external passage/carport/garage
  • Floor joists
  • Floor joists and soffit boards
  • Rainscreen framing
  • See Metal flashings for corrosion issues
  • See batten, metal framing and fastenings for corrosion issues
  • Access panels and doors
  • To service risers
  • Water, Gas, Electricity, Telephone, Broadband, Satellite
  • RWP, RWHP, SW&VP
  • Meters: Electric, Gas, Water
  • Gas ventilation issue and Gas Regs.
  • Water stop valves, drain cock, outdoor taps,
  • Gulley below (low risk of sewer gas)
  • Easy replacement areas
  • Eaves abutting gable
  • Rainwater gutter persistent overflow risk area
  • Splash zone
  • Detail Design
  • General
  • Meet service life with minimal maintenance
  • 1st line of defence: Design to reduce risk
  • 2nd line of defence: Durable – sapwood or + preservatives
  • Control of moisture
  • Generally
  • Always assume rain-screen principle
  • Cladding largely protects membrane from wind, rain, daylight and sunlight
  • Amount of rain penetration depends upon design of cladding
  • Open jointing more rain penetration
  • Overlapping less rain penetration
  • Open cavity should always be provided
  • Drain any moisture penetration
  • Ventilate to dissipate any internally generated vapour
  • Maintain equal moisture content in both faces of boarding
  • Avoid distortions
  • Minimum 19 mm. wide
  • Usually dictated by the batten size (minimum 38 x 38 mm.)
  • Minimum 15 mm. at flashings
  • Maintain moisture content (MC) below 22%
  • No risk of Fungal attack (UK)
  • Little risk of Insect attack (UK)
  • Risk of Termite attack (Not UK)
  • Wetting to higher than 22% will not instigate decay
  • Sustained exposure above 22% increases risk of attack
  • UK typical ambient humidity and direct exposure to rain unprotected externally
  • Not raise MC above 20%
  • BS 1186:Part 3 suggests 19%
  • Climate change increase?
  • Principles
  • Avoid contact with porous surfaces
  • Avoid contact with wetted non-porous surfaces
  • Prevent wood from absorbing moisture
  • Particularly the absorbent end grain
  • Waterproof membranes or air gaps required
  • Protect top edges of vertical boards
  • Ventilate bottom edges of vertical boards: 15 mm.
  • Ventilate side edges of horizontal boards: 8 – 10 mm.
  • Ventilate bottom ends of diagonal boards: 12 mm.
  • Sloping flashings to splash away from board ends
  • Avoid sealants
  • Backgrounds
  • Masonry background
  • Waterproof membrane not needed
  • Other backgrounds
  • Waterproof membrane behind battening
  • Bases
  • 15 mm. clearance above flashings
  • Abutments
  • 8 – 10 mm. clearance
  • 12 mm. clearance from diagonal boarding
  • Ensure water runoff cannot enter behind this joint
  • Overhangs
  • Generally
  • Largely protect walls from direct wetting
  • Wind driven rain gets everywhere
  • Extend the life of surface finishes
  • Not affect the durability of the wood
  • Unfinished
  • Will slow or prevent natural weathering and bleaching
  • Result in uneven colouring between shaded and unshaded
  • Horizontal surfaces
  • Ground, pavement, flat roofs, decking, etc.
  • Smooth surface splash higher
  • Irregular large gravels disperse splashes
  • Water can sit on surface
  • Consider permeable surface
  • Indirect wetting from splashing
  • Greater wetting of lower boards
  • Deterioration of surface finishes
  • Possible algal growth
  • 200-250 mm. clearance advisable
  • Allowing for moisture movement (MM)
  • General
  • Organic material: Moisture Content (MC) varies with environmental conditions
  • MC varies:
  • Maximum 22% North face winter
  • Minimum 10% South face summer
  • Higher and lower % are occasionally recorded
  • Seasonal variation on one face varies: 6-8%
  • Change in moisture content won’t affect strength or durability
  • Avoid restraining fixings or tight jointing
  • Risk of splitting cupping or bowing
  • Excessive moisture movement: T&G can disengage
  • May compromise the fixing to the building
  • Design to accommodate MM Moisture Movement
  • Design in allowances for MM Moisture Movement
  • Match MC in use to MC at construction
  • UK normal MC range: 12% – 20%
  • BS 1186:Part 3 suggests: 13% – 19%
  • Aim to obtain timber of 16% mean MC
  • Aim to fix timber at __% mean MC
  • Design joints to accommodate shrinkage and swelling
  • Generally
  • Limit board widths to 150 mm. to limit variation in size
  • Especially if used Green
  • Overlapping
  • Overlapping more tolerant and remain watertight
  • Open joint
  • Open joints more tolerant remain watertight
  • Rebated
  • Rebated less tolerant and may not remain watertight
  • T&G Tongue and Groove boarding
  • Limit board widths to preferably 100 mm. maximum 125 mm.
  • Tongue uppermost
  • T&G less tolerant and may not remain watertight
  • Movement in T&G boards can make assembly difficult
  • T&G boards movement can lead to tongue splitting off
  • Only kiln dried to recommended MC should be used
  • Fixing and fasteners to accommodate moisture movement
  • Board Widths
  • Below 100 mm. single fixed
  • Reduce batten spacing
  • Up to 100 mm. single fixed
  • Shrinkage either side of fastener
  • Over 100 mm. double fixing to help them stay flat
  • Stresses between fasteners
  • Changes in shape
  • Moisture content variations
  • Natural tendency
  • Predictable
  • Turn to advantage
  • Section cut from tree
  • side nearest the heart of the tree expands relatively (heart side)
  • side furthest from the heart side shrinks relatively
  • edges cup away from the heart side
  • Arrange for joints between board to tighten against each other
  • Most boards:
  • Heart side to face outward when section installed
  • Board on board
  • Inner board
  • Heart side inwards to face building
  • Outer board
  • Heart side outwards to face away
  • Quarter sawn boards have least risk of changing shape
  • Uneconomical to use quarter sawn throughout
  • Cladding support: battens and counter-battens
  • Battens to which boards are fixed
  • Battens usually dictate the ventilation zone depth
  • (minimum 19 mm.)
  • Vertical cladding, Horizontal Battens Size:
  • Dictated by board fastener and board thickness
  • Nails
  • Nails normally driven just below the surface
  • allow for timber shrinkage
  • avoiding nail becoming proud of surface
  • Nails 20 mm. from end of board
  • Nails 15 mm. from edge of board
  • Spacing: batten spacing dictates.
  • Small head or siding nails can pull through soft WRC
  • Larger heads recommended for WRC
  • Standard Round wire nails:
  • 2.5 x thickness of board
  • T&G: 19-22 mm. = 48-55 mm.
  • Other: 16-19 mm. = 40-48 mm.
  • Annular ring-shank nails
  • Improved holding power
  • 2 x thickness of board
  • T&G: 19-22 mm. = 38-44 mm.
  • Other: 16-19 mm. = 32-38 mm.
  • Pneumatically driven nails
  • D shaped heads may not be visually acceptable
  • Virtually headless pins are not recommended
  • Screws:
  • Minimum 2 x thickness of board
  • T&G: 19-22 mm. = 38-44 mm.
  • Other: 16-19 mm. = 32-38 mm.
  • Batten Size:
  • Minimum 2 x board thickness
  • T&G: 19-22 mm. = 38-44 mm.
  • Other: 16-19 mm. = 32-38 mm.
  • Minimum: 38 x 38 mm.
  • Batten profile:
  • Horizontal boarding vertical batten
  • Square
  • Vertical boarding horizontal batten fixed to counter-batten
  • 15 degree sloping top face to throw off water into ventilation cavity
  • Vertical board on board horizontal batten
  • 15 degree sloping top face to throw water away from sheathing and breather face
  • Counter-battens, studs, joists or rafters
  • Spacing of nails or screws dictated by this spacing
  • Usually fixed vertically or running down slope
  • Reduced centres
  • Helps reduce tendency for boards to twist, bow or cup
  • Green timber cladding
  • Centres reduced to 400 mm. (maximum 500 mm.)
  • Narrow boards (less than 100 mm.)
  • Centres reduced to 400 mm.
  • Vertical or horizontal boards
  • Not greater than 600 mm. centres
  • Diagonal boards
  • Vertical or horizontal battens
  • Not greater than 400 mm.
  • Diagonal battens
  • Not greater than 600 mm.
  • Counter-batten size:
  • To maintain 19 mm. ventilation zone
  • Vertical boarding:
  • Counter-batten size: 16 x __ mm.
  • Perimeter battens
  • Omit or reduce thickness of any perimeter battens (top and bottom of horizontal boarding)
  • Maintain 19 mm. ventilation zone
  • Resource Efficiency
  • Reduce waste in design
  • Obtain knowledge of what is available: width and length
  • Design with available width and length in mind
  • Choose species according to preferred design width and length
  • Design for Demountability
  • Fasteners
  • Screws
  • Accessible heads
  • Corrosion resistant to enable unscrewing later
  • Nails: Avoid
  • Metal
  • Future reuse as screw essential
  • Corrosion resistant
  • Austenitic stainless steel
  • Grade: 304 or 316 (marine grade)
  • Corrosion resistant finish
  • Susceptible to damage when driving
  • Reclaim for reuse
  • Care with fixings avoid damaging boards
  • Use screwdriver in reverse to remove screws
  • Assemble multiple pallets to support lengths
  • Strapping to secure, timber strips to protect
  • Waste issues
  • Hazardous waste (treated or coated)
  • Active Virgin timber
  • Compostable waste (perishable species)
  • Mixed waste (treated or coated)
  • Samples & Mock-ups
  • Samples
  • Require sufficient samples prior to purchase
  • Purpose
  • Agree visual quality of profile
  • Check size of section
  • Agree visual quality of timber
  • Knots
  • Sapwood
  • Colour range
  • Agree finish: surface texture, transparency, colours, gloss level
  • Timing
  • In advance of purchase deadline to meet programme
  • Programme may include mock-up construction and approval process
  • Mock-ups
  • Position:
  • as if in real building
  • Height, distance and viewing angles
  • for accurate judgement
  • in the real building
  • if acceptable, as part of the final works
  • Large enough to include:
  • Long lengths of timber, butt joints
  • Background build-up, framing,
  • boundaries, edges
  • Internal and external changes of direction,
  • Openings,
  • Changes in design
  • Purpose
  • Check interfaces with other trades
  • Ensure required quality can be achieved
  • Agree acceptable quality if different
  • Timing
  • In advance of purchase deadline to meet programme
  • Drawings
  • Standard Details
  • Show the proposed construction details (fixed)
  • Principle Details
  • Show the ideal details (fixed)
  • but offer designers some choices about:
  • size, profile, species, finishes (unfixed)
  • Materials handling and storage
  • Materials can be spoiled and repairs may be impossible or unacceptable
  • Wasting materials is unacceptable practice
  • Risks
  • Exposure to excessive wetting
  • Exposure to mud splashes
  • Exposure to cement slurry splashes
  • Damage by foot traffic boot marks
  • Damage by impact
  • Protection
  • Protection is essential in transportation, storage and once installed
  • Storage
  • Avoid over tight banding
  • Protect edges of boards from damage
  • T&G vulnerable
  • On solid flat (shallow slope to self drain) surface
  • Dry concrete suitable
  • Lime stabilised soil suitable
  • Avoid soil base (mud splashes)
  • Away from traffic flows (mud splashes)
  • On battens or pallets to prevent contact with soil and ground water
  • Batten spacing to prevent deflection of stack or individual boards
  • Undercover and ventilate
  • Exclude moisture but encourage moisture egress
  • Green timber
  • Consider stacking with sticks between layers
  • Ventilation to reduce moisture content
  • Sticks must be clean and dry to avoid stick marking
  • Unfinished installation boards
  • Special care to keep clean and dry and free from soil and cement splashes and damage
  • Sawn finishes impossible to sand to remove marks
  • Natural weathering of any marks: long slow process
  • Prefinished boards or panels
  • Avoid damage of finish
  • Avoid touching up as it is difficult to do well
  • Colour matching
  • Gloss level matching
  • Blending in
  • Loss of durability compared with factory applied
  • Installation
  • Moisture content
  • At time of installation is important
  • As specified
  • Check and record immediately before installation
  • It may be different to when delivered
  • Condemn timber for use on the project if MC drops by _ %
  • Heartside arrangement
  • Normal boarding
  • Symmetrically profiled boards
  • If growth rings are visible in cross section of boards
  • Ensure heartside is on outer face
  • Board on board
  • Inner board heartside to face inwards to wall
  • Outer board heartside to face outward
  • Care with kiln dried and sawn timber this may reverse requirements
  • Allow for moisture movement: Expansion
  • 2 mm. gap for up to 150 mm. wide T&G
  • What gap for larger?
  • Allow for moisture movement: Shrinkage
  • Green timber will shrink on drying
  • Provide less gap
  • T&G not suitable for Green Timber
  • Open joint setting out should make joints narrower so they are correct once dry
  • X mm. per xxx mm.
  • Determined by calculation
  • Butt jointing boards
  • Unfinished timber: 5 mm. gap
  • Coated timber: 8 mm. gap
  • Always occur on doubled battens
  • Random length: add additional batten, length: ≥ 3 x board width
  • Expressed joint in panels: add second batten
  • Thicker or narrow hardwood boards
  • Form lap joint by rebating ends and overlap
  • Labour intensive and requires good workmanship
  • Nominal and finished sizes
  • Allow nominally 6 mm. reduction in section size (3 mm. from each face)
  • If cladding is based on nominal size and coordinated with openings
  • increase joint sizes to compensate
  • Unfinished boards and fasteners
  • Drive nail or screw heads flush after initial drying has taken place
  • Coated boards
  • Arrises
  • Removal of sharp square arises will prolong the life of the coating
  • Planning chamfers or sanding
  • Coating cannot negotiate sharp corners
  • Surface tension in liquid coating pulls them back from corners
  • Benefits horizontal boards in particular
  • fasteners
  • Drive nail or screw heads slightly below the surface for slight paint build up
  • Application on site
  • Minimum of first coat to be applied before installing
  • Apply thickly to exposed end grain
  • Pre-coating on all faces will even out moisture absorption
  • help even out distortion across the section
  • Avoid uncoated material showing when shrinkage occurs
  • Open joint boarding
  • Coat battens as well
  • Maintenance
  • Unfinished boards
  • Unfinished shingles and shakes
  • Little or no maintenance
  • Surface cleaning from pollution or foliage
  • Surface cleaning
  • Cleaning agents
  • For removal of surface staining or soiling
  • For removal of beached surface
  • For removal of iron staining in acidic timber
  • Stubborn stains may require a clear coating
  • Clear coating have low UV resistance
  • Will need recoating frequently
  • 2-3 years or less
  • Wetting stains may benefit from clear coating
  • To reduce water uptake
  • Only apply after drying out
  • Clear coating have low UV resistance
  • Will need recoating frequently
  • 2-3 years of less
  • Test small patch to check appearance
  • Life expectancy
  • Depends on many factors:
  • Level of exposure
  • Initial application method
  • Factory applied will outlast site applied
  • Factors include:
  • Tightly controlled process
  • Controlled moisture content
  • Limiting exposure to UV light before application
  • Cleanliness of environment
  • Standards of workmanship
  • Long life coating may require special preparation for maintenance
  • Consult manufacturer of coating and component
  • Always check for compatibility of all layers
  • Check O&M manuals (Operation and maintenance manuals)
  • Do not overcoat micro porous coating with film forming coatings
  • If reapplying same coating check preparation rules
  • Patchy clear stain will need to be stripped back to bare wood
  • Minimise preparation time by maintaining before deterioration sets in
  • Hardwoods coating for first time after being left unfinished
  • Hardwood vary considerably
  • Some are not suitable for coating
  • Need for decoration depends on exposure
  • The most exposed will require more frequent redecoration
  • Less exposed need not be coated at same frequently as exposed
  • Survey and determine needs
  • Update O&M manuals

H21      TIMBER WEATHERBOARDING

BACKGROUND INFORMATION

  • Environmental Issues
  • Forest as Resource
  • Support for people
  • Home for people
  • Medical resource
  • Food resource
  • Shade grown coffee
  • Support Biodiversity
  • Home for nature
  • Food source for nature
  • Food for nature when dead
  • Timber
  • Biomass Fuel
  • Building material Carpentry and Joinery
  • Furniture and Cabinet making
  • Carbon sink (Carbon Sequestration) when growing
  • Consumes Carbon dioxide
  • Produces Oxygen
  • Mature trees reduce efficiency
  • Harvesting of plantation is good if replanting
  • Occupants
  • Occupation by indigenous tribes
  • Occupation by wildlife
  • Legality
  • Legal ownership of land forest plantation
  • Occupation rights
  • Legacy
  • Clear felling destroys most future opportunities
  • Clear felled land rainwater runoff overwhelms rivers
  • Runoff deposits soil in river estuaries
  • Soil in solution in rivers can starve fish of oxygen
  • Soil deposits pollute and kill corals
  • Farming chemicals create dead zones in rivers, estuaries and coastal waters
  • Plantations
  • Plantations can restore status quo and avoid many of these issues
  • Plantations likely to be monocultures
  • Limited support for biodiversity
  • Trees may not be indigenous species
  • Coffee, Chocolate, Poppies, Drugs, Soya bean,
  • for animal feed or bio-fuels, soap
  • recreational drugs
  • Resource if maintained
  • Medical resource
  • Food resource
  • Shade grown crops in harmony with forest canopy
  • Wildlife habitation/resource
  • Indigenous tribes
  • Carbon sequestration & oxygen generation
  • Selective cropping
  • Removal of individual trees can be done
  • Leaving forest to heal in relatively short time
  • Access roads give farmers access
  • Farmers burn and clear fell to make farms for cattle
  • A few years in the soil fertility is gone
  • Soil erosion after cattle disturbance
  • Farmers moves on to repeat process in new location
  • Environment Sustainability
  • Rapidly renewable coppicing for biomass fuel
  • Rapidly renewable forest thinning timber
  • for some construction applications
  • Renewable tree growing 40 – 100 year cycle
  • Use of sun, water and minerals from ground
  • Energy for loggers
  • Energy for transportation
  • Energy for milling and craftsmen
  • Energy for shipping and transport
  • Factors influencing choice of species
  • Local sourcing
  • Home grown v imported
  • Local employment
  • Local economy
  • Transport minimised
  • Fuel use
  • Pollution
  • Congestion
  • Manufacturing
  • Energy
  • Emissions
  • Simple sawn profiles v profiled
  • Energy used
  • Waste generated
  • Efficient use of resource
  • Reduce
  • Reuse
  • Recycle
  • Recovery: Composting v energy from combustion
  • Reject Waste: Disposal
  • Erection
  • Local labour v imported
  • Finishes
  • None v stained v painted
  • Natural v Synthetic
  • Plant extract v Petrochemical
  • Perfume v VOCs
  • Materials:Waste 1:20
  • Compostable v Hazardous waste
  • Durability
  • Durable v Preservatives
  • Maintenance
  • None v over-coating v stripping and repainting
  • Disposal
  • Composting of untreated unfinished timber
  • Hazardous waste if treated or finished
  • Performance in use
  • Desired performance
  • Service life
  • Appearance
  • Costs
  • Zones of influence
  • Sun
  • Sundial
  • Solar shading in summer
  • Solar penetration in winter (deciduous)
  • Light
  • Shading
  • Dappled light
  • Colour from translucency of leaves
  • Reflection on leaves and wet leaves
  • Wind
  • Shelter
  • Wind noise in leaves and through branches
  • Wind shadow
  • Rain
  • Temporary shelter
  • Long term shower
  • Dry spot slowly disappears
  • Lightning
  • Tall trees: lightning magnet
  • Root zone
  • Water harvesting
  • Soil shrinkage
  • Building settlement in extreme droughts
  • Pavement disruption
  • Production
  • Pollen drift
  • Sap
  • Perfume
  • Allergic reactions: Hey fever
  • Seed drop
  • Leaf drop in autumn
  • Biodiversity support
  • Nectar bar
  • Fruit and nuts
  • Home for flora and fauna
  • Cost plan
  • Treated Softwood: £60-69/m2
  • Durable Hardwood: £64-75/m2
  • Sustainable Definition?
  • England
  • Domestic
  • Code for Sustainable Homes
  • Non-domestic
  • Pending
  • Not England
  • Domestic
  • BRE EcoHomes
  • Others?
  • Non-domestic
  • BREEAM, etc.
  • LEAD
  • DREAM
  • CEEQUAL
  • BRE Green Guide to Specification
  • (2002 EcoHomes & BREEAM))
  • Treated SW: 2002 A rated
  • Durable HW: 2002 A rated
  • Reclaimed and reused timber: A rated
  • (2008 CfSH Green Guide)
  • Treated SW: 2008 A+ rated
  • Durable HW: 2008 A+ rated
  • Reclaimed and reused timber: A rated
  • Timber types
  • Coniferous (Softwood)
  • Durable softwood
  • Green Softwood
  • Perishable softwood
  • Treatment
  • Acidic Softwood (tannin staining/corrosion potential)
  • Western Red Cedar
  • Deciduous (Hardwood)
  • Durable Hardwood
  • Green Hardwood
  • Perishable Hardwood
  • Acidic Hardwood (tannin staining/corrosion potential)
  • Oak
  • Sweet chestnut
  • Timber merchants
  • Need to be familiar with numerous issues
  • Strength grades (is not enough)
  • Quality grades
  • Sustainable Forestry Certification
  • Chain of custody
  • Treatment certification
  • H21 Sector
  • Manufacturers or suppliers
  • Softwood for batten
  • Treatment for battens
  • Hardwood for battens
  • Softwood for boards
  • Treatment for boards
  • Hardwood for boards
  • Decorative coatings
  • Fasteners
  • Meshes
  • Membranes???
  • Installers and applicators
  • Treatment
  • Installation
  • Applications
  • Maintenance
  • Contractors
  • Designers

© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
26th February 2016 – 7th November 2020

GBE H21 Timber Weatherboarding Outline
Images:


H21Outline

 


© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
26th February 2016 – 7th November 2020

GBE H21 Timber Weatherboarding Outline
See Also:


More about Timber Weatherboarding


GBE Outline


GBE CPD

  • H21 Timber Weatherboarding (Handout) (CPD)

GBE Shop

  • H21 Timber Weatherboarding (Show) (PDF)

GBS Robust Specification


GBE Projects: Information


GBE Data Sets

GBE Shop


GBE 6 Core pages

GBE Suppliers

  • FSC Suppliers

GBE Installers

  • Company names

GBE Systems

  • System Reference: __

GBE Accessories

  • Accessory Reference: _

GBE Manufacturer

  • Company name

GBE Materials

FSC Timber Suppliers

GBE Collaborative Services


© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
19th April 2016 – 7th November 2020

GBE H21 Timber Weatherboarding Outline G#10281 End

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