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GBE Performance Gap (Opinion) G#41216

Brian Murphy aka BrianSpecMan BRM @ Build4 CAPEM Showroom

GBE Performance Gap (Opinion)

GBE > Encyclopaedia > Opinion > State of the Industry > G#41216

About:

Scope/Extract:

  • These Opinion Posts have the potential to contribute to filling part of the ‘knowledge-gap’ and I am planning to ring every bit of 50 years of experience in violet construction, 40 years of specification consultancy and 24 years of green construction into its content.
  • GBE Continuing Professional Development (CPD) seminars will also be created and published to support this paper and its promotion.

Performance-Gap (Opinion):

Problems:

  • Zero Carbon Hub (ZCH) was Government funded until Zero Carbon targets were dropped.
  • Subsequently green-washy Net Zero Carbon targets were introduced to let Business as Usual (BAU) prevail and green-washing carbon offsetting take its place.
  • Now that the Conservatives are likely to get voted out, they have started dropping Net Zero Carbon ambitions to make whoever follows look incompetent when targets can no longer be met by any Government nor by UK Business.
  • ZCH surveyed residential developer sector outputs and compared designed performance with actual performance.
  • ZCH coined the term ‘Performance-Gap’ to describe the incompetence of this sector’s outputs.
  • Most of the ZCH research and findings were related to heat loss and overheating.
  • In the post-Grenfell ensuing competency tsunami, designers will increasingly be expected to have competency related to fire initially and as it influence progresses, competency in all aspects of building performance.

The following consider moisture entering, within and exiting timber construction:

In Building Regulations Approved Documents (BRAD) order:

BRAD A Structure:

  • Timber affected by prolonged excess moisture will be prone to risk of infestation, mound, rot and worse.
  • Rot at ends of sections of timber may prevent transfer of loads between parts supporting each other and ultimately down towards foundations.
  • Rot at side or edges of sections of timber may diminish the capacity of the section to resist loads.
  • Rot or fire at any surface will diminish the section’s ability to carry the load.
  • Not building in flood plains:
    • Despite Government letter to Planners giving developers permission to develop flood plains.
    • Environment Agency (EA) (1 of 6 consultees) have no teeth, cannot stop Government stupidity.
      • Recommend: ‘sacrificial construction’ to fill landfills after a flood.
      • Not suggesting or demanding flood tolerant, floating or building on stilts.
    • Scottish Environment Protection Agency (SEPA) overrule English Government.
  • Choice of species or reclaimed timber with durability to resist being immersed in flood plain or sea water.
  • Building on stilts and/or piling or floating foundations/building.
  • Ashwells timber: Regularly have reclaimed Greenheart timbers from river, canal or sea walls.
  • Flood tolerant construction:
    • Using materials that are solid, high density, not perforated, not permeable, not absorbent, not affected by moisture.
    • Bunded sites: when EA permit defensive protection of individuals at the expense of others.
    • Tanked construction to exclude water or to drain water.
    • No hollow construction, no cavities, only solid walls.
    • Masonry: Fired clay solid bricks, engineering bricks, glazed terracotta, granite stone.
    • Non permeable conductivity thermal insulation: E.g. Expanded polystyrene, Cellular glass.
    • Damp proof membranes or flood coats around insulation
    • Accommodation above anticipated flood level, accommodation in upper floors.
    • Building in stilts to raise accommodation above anticipated flood level.
    • Services above anticipated flood level.
    • Finishes below anticipated flood level: glazed ceramic, quarry tile, porcelain, etc. to floors and walls.
    • Permeable perimeter to avoid buoyancy.
    • Hose down and flush out flood residues, back in business next day.
  • Floating construction:
    • In its simplistic form:
      • Form factor of building’s plan to be compact to reduce torsion on foundation.
      • Reinforced concrete raft foundation, rigid enough to resist differential settlement and expansion on moisture affected subsoil. E.g. Peat, clay and sand
      • Services must accommodate differential settlement, hinging pipelines in long manholes.
    • More sophisticated:
      • Reinforced concrete or steel sheet pile watertight tank.
      • Reinforced concrete waterproof hollow raft foundation constructed inside and isolated from that tank.
      • Flexible services connections to accommodate vertical movement.
      • Steel or timber guides to control and restrain the vertical movement of the hollow raft in the tank.
      • Flood water enters the tank and the hollow raft rises with its own buoyancy.
    • Building on Stilts:
      • Reinforced concrete, corrosion protected steel piles or steel sheet piling or durable timber piles.
      • Raised platform on top of piles above anticipated flood level.
      • Prefabricated MMC construction or insitu construction superstructure on raised platform.

BRAD B Fire:

  • The only time moisture could be seen as an advantage in timber, however once heat drives off moisture vapour then the timber will be as vulnerable to fire as ever.
  • Impregnation treatment can make timber less vulnerable to fire, temporarily raising the moisture content to get the salts solutions into the timber section, then excess water or solvent evaporated, or vacuum sucked back out leaving the salts behind in the timber.
  • Fire at any surface will diminish the section’s ability to carry the load.
  • Soluble salts in timbers can be flushed out by exposure to persistent rain.
  • Exposed external timbers need to be protected from weather and precipitation.

BRAD C Site Preparation and resistance to contaminants and moisture:

  • Problem:
    • Site preparation:
      • Prolonged excess moisture in timber makes it vulnerable to rot, infestation by mould, insects including termites, ultimately to loss of integrity and structural failure.
      • Timbers embedded in, or in contact with, topsoil, plants and sub-soil puts them at risk of shorter life.
      • Timber piles made from virgin or reclaimed species hardwood.
        • Architectural Salvage yards have reclaimed Greenheart piles/harbour walls.
      • Fence posts and gravel boards are particularly vulnerable.
      • Timber Decking framing, supports and upstands risers are all vulnerable
        • Perimeter risers will restrict ventilation of enclosed voids and put all timbers at risk of premature failure.
      • Resistance to contaminants:
        • Radon or methane gases unlikely to affect embedded timbers, unless methane is ignited.
        • Radon and methane could find their way into the cells of timber.
        • Radioactive timbers from failed nuclear powerplants have been distributed widely and have been detected in UK Architectural Salvage yards, now permanently removed for safety.
      • Resistance to Moisture Vapour:
        • Damp proof membranes will keep ground water away from embedded timbers.
        • Vapour barrier membranes will keep water in substrates away from supported timbers.
        • Moisture ingress can adversely affect thermal insulation performance and durability.
      • Resistance to water entry:
      • Resistance to rodent and insect infestations:
        • Excessive and persistent rain and rising water table encourages rodents and insects to enter buildings.
        • Insects can get through very small holes.
        • Insect barrier meshes included at the top and bottom of ventilation zones in weatherboarding and rainscreen claddings are only designed to exclude wasps, bees and hornets, anything smaller gets in.
        • A hole the size of one finger thickness is sufficient for a mouse entry.
        • A hole the size of two fingers thickness is sufficient for a rat entry.
        • Mice and rats front teeth grow continuously, and they need to gnaw to wear them down.
        • Timber and electrical cables are vulnerable materials.
        • Small holes can be gnawed at making them into larger holes giving access.
        • Holes in the external envelop make buildings air leaky for heat, coolth, wind, fire, noise, moisture vapour or precipitation, putting building fabric materials at risk of mould and rot.
  • Building occupation by nature:
    • An important thing to mention:
      • Bats do not do damage, their claws hang from timber or roofing underlay
      • Oils from their fur will discolour surfaces.
      • Bat droppings are dry.
      • There is very little bat urine, that will evaporate away.
      • Bats should not be likened to mice or rats.
        • (even though Germans incorrectly call bats ‘flying mice’ ‘fledermaus’).
      • Birds and bats will occupy buildings via access holes to attic and other spaces beyond.
      • 25 mm diameter hole is sufficient for numerous bird species.
      • 25 x 50 mm hole is sufficient for small bats and birds.
      • Bigger holes let in bigger species of bat and bird.
      • Some holes can be tunnels with changes of direction to prevent unwanted birds from entering.
      • Holes in the external envelop make buildings air leaky for heat, coolth, wind, fire, noise, moisture vapour or precipitation, putting building fabric materials at risk of mould and rot.
      • Cold loft or attic spaces are outside of the U value envelop and can be made use of to invite wildlife in without compromising energy use or energy demands.
      • Bats can be noisy neighbours, use acoustic insulation or roost around them.
      • Bats are protected species and cannot be excluded or trapped inside.
      • £5000 fine per bat and imprisonment are possible for interfering with bats.
      • Even with a Natural England issued licence, if abused.
  • Solutions:
    • Site Preparation:
      • Problems:
        • Avoid embedding timbers in sub-soil,
        • Avoid using insufficiently durable timber species in flood prone sites.
        • Timber used below flood plain historic records and future risks.
      • Solutions:
        • Provide a foundation stone or concrete plinth set into the sub-soil, at a competent depth,
        • Project at least 150 mm above the finished ground level,
        • With a flattened level top of similar size to the following timber posts,
        • Place and centre a load bearing lead square damp proof course and place the post on the lead, there might be a dowel to connect the parts.
      • Problems:
        • Choose durable timbers, but even Class 1 Very durable English Oak only has a 25+ year life expectancy in contact with inert subsoil, less in contact with active topsoil.
        • Preservative treatment: impregnation or coating of embedded timber.
        • Cast fence and decking posts in fast-acting high-chemistry, high-carbon, high-energy, fence post concrete.
        • Cast fence and decking posts in high-carbon, high-energy concrete.
      • Solutions:
        • Cast fence and decking posts in slow strengthening limecrete, laterally restraining until set and strengthened.
        • Driven metal stakes with sockets to receive fence posts allow fences to be installed without embedding them in subsoil.
        • Sleeving: adhering a damp proof membrane around the embedded section, preventing moisture and oxygen reaching the timber
        • (E.g. BBA Product Available)
        • Using gravel or sand filter drains around the fence and decking post my help rain and ground water to drain away from timbers but might also provide easy access for rising ground water table.
        • Filter drains must be connected to surface water drains, soakaways or sustainable urban drainage sumps.
        • Insect barrier meshes included at the top and bottom of ventilation zones in weatherboarding and rainscreens are designed to exclude wasps, bees and hornets.
      • Retrofitting embedded timbers:
        • Temporarily support structure to take weight off structural timbers.
        • Remove and replace affected timber.
        • Support reduced length timbers in metal joist hangers outside of the wall thickness.
        • Plastic top hat covers (designed for airtightness) to ends of timber to be re-embedded.
      • Resistance to contaminants:
        • Gas proof membranes (GPM) could keep radon or methane away from embedded timbers.
      • Resistance to water and moisture vapour:
        • Damp proof membranes (DPM) will keep ground water away from embedded timbers.
        • Vapour barrier membranes will keep water in substrates away from supported timbers and linings.
        • Membranes should resist moisture ingress, potentially affecting insulation performance, but may also be chosen to permit entrapped moisture egress.
        • Sealant work is essential between rigid and more flexible or movable materials or components.
        • When sequence of work dictates multiple seals may be necessary:
          • Bathroom refitting: the bath may be sealed against wall lining or plastering, and later also sealed between ceramic all tiling and bath; a leak in the second will be defended by the first.

BRAD D Toxic Substances:

  • Problems:
    • Off-gassing from preservative treatment.
    • Off-gassing from adhesives and coatings.
  • Solutions:
    • Avoidance of preservative treatment by design.
    • Mechanical fastenings in place of adhesives: screws, nails, bolts.
    • See other TDUK Technical Guide.

BRAD E Resistance to the passage of sound:

  • Problems:
    • Excessively dry timber construction could open-up joints making them gappy and permitting noise access inwards or egress outwards.
  • Solutions:
    • Wood fibre-based insulation is an excellent acoustic performer: Insulation, Isolation, absorption.
      • A well-insulated house using wood-fibre insulation: you will see but not hear fireworks.
    • Cellulose fibre (recycled newspaper) flake is available at an acoustic insulation density.
    • Many other effective acoustic plant-based insulation materials are available.
      • g. Hemp, Sisal, Cotton, Coconut husk, Coir, Straw, Cork, etc.
    • Dry sand,
      • But energy to dry the sand can be problem.
      • Site rewetting is possible.
      • Membranes may be needed to bund an area where dry sand is deployed.

BRAD F Ventilation:

  • Scope:
    • Provides guidance on building ventilation, including building indoor air quality and preventing condensation.
    • Permanently on mechanical extraction ventilation is not a viable solution.
    • Case study: The default solution for residential apartments in Salford & Manchester area, by one developer.
    • Permanently on mechanical ventilation with heat recovery (MVHR) solves on issue but remains a problem.
  • Problems:
    • Timber exposed to excessive prolonged moisture content is vulnerable to mould and rot.
    • Increasing ventilation targets
    • Trickle vents in windows are required by Building Regulations.
    • Trickle vents in windows compromise Mechanical Ventilation with Heat Recovery (MVHR)
    • Breathing construction is not a substitute for ventilation.
  • Solutions:
    • Slogan: Build Tight Ventilate Right
    • Passive ventilation is the solution for timber exposed to excessive prolonged moisture content.
    • Timber can be salvaged from these conditions by the removal of the moisture source, solar heat gains and warm dry air to dry it out and passive ventilation to keep it away.
    • Purposeful Preventative Ventilation:
    • Roofs: Regulations: x mm2/m run along eaves and verges
    • Eaves to roof space to eaves: 50 mm
    • Vertical walls: Ground to eaves 50 mm or batten depth
    • Via purpose made pitched roof vent tiles at eaves and ridge

BRAD G Sanitation, Hot water safety and water efficiency:

  • Problems:
    • Hidden pipes make inspection and maintenance more difficult.
    • Leaky appliances, pipes or valves
    • Uninsulated hot pipes squander energy:
      • After insulating a building well, hot pipes become a most important source of heat loss.
      • Hot water and heating pipes, any pipe transferring heat or coolth.
    • Uninsulated hot water pipes run below uninsulated cold water pipes risks condensation on the cold pipes.
    • Condensation dripping onto and into timber construction.
    • Overflow warning pipes from WC cistern, Cold water tank in attic:
      • Positioned over paths so they could not easily be ignored.
      • Horizontal discharge pipes served their purpose.
      • Somebody decided wind blowing back into the pipe needed to be stopped.
      • A tee was added at end of pipe to stop wind blowing back onto building.
      • Now water leaving the vertical outlet of the tee with a little centrifugal force, discharges over the wall, goes unnoticed, saturates the wall, encourages mould.
  • Solutions:
    • Pipes need to be accessible to inspect and maintain.
    • Case Study: Formerly Building Research Establishment ‘bre’ Campus’s Integer House:
      • A narrow 300 mm duct between two bathrooms with a 300 mm door into it.
      • Provides accessible duct space where all services are exposed, visible, checkable (check if insulation is added and still intact), accessible, modifiable, improvable (E.g. add insulation), maintainable, removable, reclaimable, upgradable.
      • Able to add new services as they are invented and introduced.
    • Smart meters can be used to detect excess and overnight water use, which may indicate a leak.
    • Leak detection and flood avoidance valves can be fitted to water consuming appliance connections.
    • Avoiding and quickly repairing leaky appliances, pipes or valves is essential to the durability of timber buildings.
    • g. Valve
    • Act quickly and insulate all hot and cold water and heating pipes to reduce risks of condensation dripping onto and into insulation and timber construction.

BRAD H Drainage and waste disposal:

  • Scope:
    • Roofing, cladding, gutters, downpipes, down chains, gullies, outdoor taps
  • Problems:
    • Timber rainwater gutters need to avoid increases in or prolonged exposure to moisture content.
    • Bamboo has cell division which can cause blockages and static water in rainwater gutters.
    • Overflowing gutters and leaking downpipes.
    • Overflow warning pipes from WC cistern, Cold water tank in attic:
      • Positioned over paths so they could not easily be ignored.
      • Horizontal discharge pipes served their purpose.
      • Somebody decided wind blowing back into the pipe needed to be stopped.
      • A tee was added at end of pipe to stop wind blowing back into pipe.
      • Now water leaving the vertical outlet of the tee with a little centrifugal force discharges over the wall, goes unnoticed, saturates the wall, encourages mould.
      • Can be seen from many train rides through urban and rural areas.
    • Rainwater run-off from metal roofs or cladding could discolour timber cladding.
    • Rainwater down chains make interesting additions, but windblown water sprays everywhere, when back lit looks amazing, wind driven water goes horizontally and upwards into timber constructions.
    • Barcelona urban building blocks with square inner courtyards: rainwater is celebrated by discharging onto stone plinths and splashing everywhere.
  • Solutions:
    • Check for non-draining low points in gutters and raise them to achieve constant falls.
    • Check for overflowing gutters during storms.
    • Clean out gutter debris which will hold water in contact with timber.
    • Provide a waterproof lining to timber gutters; but ensure it is watertight and no water is trapped below it where it can encourage rot or mould.
    • Ensure all ‘flat’ flat roofs are served by competent siphonic drainage.
    • Ensure flat roofs are laid to 1 to 40 falls as designed to ensure 1 to 60 falls are achieved when deflection and creep are considered.
    • Ensure temporary down pipes are connected to gutter outlets and discharge away from building during construction to prevent water discharging down walls.
    • Ensure all roof rainwater goods are adequate size and laid to suitable falls.
    • Ensure all roof to wall abutment upstands and flashings are designed and installed competently.
    • Include gutters at eaves and at junction between vertical cladding and vertical weatherboarding.
    • Avoid rainwater down chains in the vicinity of timber cladding, absorbent materials; position them well away from the building with long cantilever gutters.
    • Do not use timber in Barcelona courtyards.

BRAD J Combustion appliances and fuel storage:

  • Problems:
    • High moisture content in biomass fuel E.g. timber, pellets, plants; can have detrimental effects upon solid fuel burners
    • Storage of timber and biomass fuel with a risk of interstitial moisture and high moisture content in a timber building is potentially risky.
  • Solution:
    • Ensure good weather exclusion at door, provide floor drainage and room or space cross ventilation.
    • Heat sources including from solar heat gains can help to dry out biomass fuel.

BRAD K Protection from falling, collision and impact:

  • Problems:
    • Handrails and balustrades where they junction with the building envelope external cladding.
    • Horizontal surfaces provide problems with rain splashes which can lead to trapped water, capillary action in rough sawn timber weatherboarding and high moisture content in concentrated points which can also lead to discolouration and staining.

BRAD L Conservation of fuel and power:

  • Problems:
    • Damp or high moisture vapour content building fabric requires:
      • Heat to dry out.
      • Extra heat to warm up the building interior for comfortable occupation.
      • Do not rely on Infra-red IR radiant heat to dry out the building, but that is an added bonus of IR heating, it should prevent build-up of moisture.
    • Improving too slowly:
      • Insulation targets (reducing energy and carbon)
      • Thermal break targets (reducing energy, carbon and condensation risk)
      • Whole building airtightness targets (Not reducing cost of heating)
    • Solutions:
      • Ensure ground level damp proof membranes (DPM) and courses (DPC) are designed and installed competently.
      • Ensure all flat flat roofs are designed and installed competently.
      • Ensure all flat flat roofs are served by competent siphonic drainage.
      • Ensure flat roof waterproofing, airtightness, breathing or vapour control membranes are designed and installed competently.
      • Ensure flat roofs are laid to 1 to 40 falls as designed to ensure 1 to 60 falls are achieved when deflection and long-term creep are taken into account.
      • Ensure shallow roof waterproofing, airtightness, breathing or vapour control membranes are designed and installed competently.
      • Ensure pitched roof underlays (RU) and breathable roofing membranes (BRM) are designed and installed competently.
      • Ensure all roof to wall abutment upstands and flashings are designed and installed competently.
      • Ensure all roof rainwater goods are adequate size and laid to suitable falls.
      • Ensure temporary down pipes are connected to gutters and discharge away from building during construction to prevent water discharging down or into walls.
      • Ensure wall vapour control membranes, breather membranes, wind and airtightness membranes and their details are designed and installed competently.
      • Better still consider switching from vapour closed construction to vapour open and breathable construction to encourage the building fabric to passively dry out over time.
      • Vapour open and breathable construction uses:
        • vapour permeable membranes (moisture vapour limiters) inside and outside of
        • hygroscopic conductivity thermal insulation (moisture vapour buffer),
        • allowing moisture vapour to flow inwards or outwards (moisture vapour pathways)
        • depending upon adjacent prevailing conditions,
        • ultimately encouraging building fabric to passively dry out over time.
      • Ensure all wind and airtightness membranes (limiters) and details are designed and installed competently.
      • Wood-fibre or plant-fibre based thermal insulation with added benefits of moisture permeability, hygroscopicity and moisture management, (moisture vapour buffer) when used in vapour open construction helps to passively dry out any entrained moisture over time.
      • Airtight construction:
        • Increasing air tightness in timber framed construction (no more gappy insulation).
        • Less moisture vulnerability of insulation and timber or permeable materials.
        • Better insulation performance
        • Higher risk of concentration of moisture vapour if air leakiness problems arise.

BRAD M Access to and use of buildings:

  • Problems:
    • Ground floors are traditionally set minimum 150 mm above ground level.
      • Related to the placing of damp proof courses in outer leaf of cavity masonry walls being set 150 mm above ground level.
      • The reason for this is to acknowledge rain drops falling on flat ground or puddled water will bounce approximately 150 mm upwards and soak adjacent wall surfaces.
    • My Grandfather, a retired clerk of works, insisted ground floor should be set 450 mm above crown of adjacent road.
      • In the event of a mains water or sewage leaks giving ample room for flood water outside, without affecting the buildings.
      • Highly unlikely target for developers who do not care about in use impacts.
    • This requires ramped paving 150 mm up towards entrance doors.
      • This puts adjacent external walls at risk from rain splashes from the ramp top surface.
    • Walk in or wheel in wet shower rooms are increasingly expected in place of bath or shower.
    • Entrance matting, pot plants and ornaments on timber decking outside of cabins or timber framed house can be a water trap that keeps decking boards persistently damp.
  • Solutions:
    • Separating the ramp (minimum 8 mm in winter) from the external wall helps prevent passage of moisture from ramp to wall.
    • Include a slot drain between ramp and external door threshold.
    • Consider using two or three courses of blue engineering bricks in door jambs above and below the damp proof course.
    • Flush thresholds permit free passage of wheelchairs and easier foot passage.
    • Floor finishes in the entrance hall could be:
      • Water resistant E.g. linoleum with coved skirtings.
      • Hygroscopic E.g. coir matting which will allow moisture to evaporate away when conditions permit.
    • Floor and wall finish in wet rooms:
      • Essential to keep timber framed construction dry.
      • Competent waterproofing to competent substrate.
      • Watertight floor, coving and wall tiles applied with full bed adhesives.
        • Not ‘dot and dab’ adhesive creating cavities for condensation or leaks.
      • Joint sealants in surfaces, competent specification and application.
        • Replace as soon as a leak is suspected or detected.
      • Splash management screens.
      • Effective falls to efficient drainage (add wastewater heat recovery plumbing).
      • Sills and shelf recesses with falls away from vulnerable joints and windows.
      • Diligent proactive preventative maintenance is essential.
    • Ceilings finishes in wet rooms:
      • Solutions: (optional approaches)
      • Moisture resistance in materials: in linings above splash zone.
        • g. Linseed impregnation in materials recipe.
        • Chemical impregnation in materials recipe.
      • Hygroscopic materials to absorb excess moisture and release when conditions improve.
        • Adequately supported against slumping.
        • Strawbale hung in ceiling void over a shower has been very effective.
      • Timber Decking:
        • Grippy surface, especially on ramps.
        • Good drainage, especially on ramps.
        • Deep drainage profiles may be challenging with wheelchair tyres.
        • Entrance matting needs to be set on a movable grid of timber to permit drainage and ventilation to allow matting and decking boards to dry out.
      • Snow and Slush:
        • Scope:
          • Door lobbies and circular doors used at external doors.
        • Problem:
          • In winter weather snow and slush including de-icing or salt attached to shoes can be dragged a long way into a building’s reception.
          • Entrance matting systems do not scrape enough snow and slush from shoes.
          • Melting snow and slush will make internal floors slippery.
          • Melting snow and slush may make the floor finish vulnerable to degradation.
        • Solution:
          • Cast in concrete or construct a sump, apply waterproof tanking, connect to foul water drainage, consider a heating, melting system, assemble support system and install entrance matting system.
          • Make sure a heated melting system cannot be left on all year without being noticed.

BRAD N Safety Glazing (withdrawn):

  • Problems:
    • Single, toughened and/or laminated glazing at the external wall will lose excessive heat energy.
    • Single, toughened and/or laminated glazing at the external wall will increase the risk of condensation on the inside face of the glass, where warm moist internal air meets cold glass, taking heat out of the air temperature, lowering the dew point, condensing moisture vapour on cold glass surfaces.
  • Solutions:
    • Condensation run off needs to be purposefully drained to a safe external location.
    • Better still only use triple glazing to reduce risk of condensation on warmer internal glass surfaces.
    • Include safety glazing in double or triple glazed sealed units at external walls if tall windows.
    • Consider hardwood internal bottom beads for durability against condensation.
    • Consider coated aluminium internal bottom beads for durability against condensation.
    • Consider coated aluminium external bottom beads for durability against weather.
    • Consider coated aluminium external beading to hardwood greenhouse and conservatory roofs.

BRAD O Overheating:

  • Scope:
    • Lightweight construction buildings
      • Wrinkly tin industrial and warehouse sheds
      • Light timber frame (LTF)
      • Light metal frame (LMF)
    • Problems:
      • BRADO & BRADL do not understand all aspects of overheating, are in conflict with each other, and are likely to create as many problems as they solve.
      • Lightweight timber frame construction is more prone to overheating by summer solar radiation through opaque roof, wall and glazed areas.
      • Lighter construction on roofs and walls do not offer the same solar protection:
        • Profiled metal roofing and cladding, Metal roofing tiles.
        • Malleable metal cladding: Lead, Zinc, Copper, Copper Alloys, Stainless steel, TCSS.
        • Roofing Tiles: Concrete, clay, slate, stone, rubber, fibre reinforced cement.
      • All loft content is subject to excess heat which should keep them dry, potentially too dry.
      • All attics overheat in sunny conditions 40 and 50 degrees C is not uncommon.
      • Excess heat in attics will conduct and radiate down to rooms below.
      • Ceiling conductivity insulation is not enough to stop attic heat passing through.
      • Hot bedrooms are not good for sleeping.
      • Upside down houses with living rooms on the upper floor are uncomfortable if heated by the loft.
    • Solutions:
      • Overheating of timber frame construction is beneficial, in that is keeps the timbers hot and dry removing a risk from moisture content putting the timbers at risk of condensation, mould and rot.
      • Masonry outer leaf or masonry solid walls provides solar protection, to the interior, reducing the risk of internal overheating.
      • Wood-fibre and plant-fibre based thermal insulation with good k value, high density and good specific heat capacity are excellent barriers to radiant solar heat gain.
      • Wood-fibre and plant-fibre based thermal insulation have the added benefits of moisture permeability and moisture management:
        • When used in ‘vapour open construction’ helps to passively dry out any entrained water or water or moisture vapour over time.

BRAD P Electrical safety – Dwellings:

  • Problems:
    • Electricity and water or moisture vapour should not come into contacts with each other.
  • Solutions:
    • Absence of water or moisture vapour is a good thing in the presence of electricity.
    • Make sure all services penetrations of water/vapour proofing membranes are designed and installed competently.
    • Ensure conduits cannot become routes for air leakage, water and moisture vapour.

BRAD Q Security in Dwellings:

  • Scope:
    • Climbable facades
    • Ledges in cladding
    • Windows and door glazing beading
  • Problems:
    • Climbable facades: Rainscreen open joints, recessed brick joints, weatherboarding all create ledges.
    • Ledges create places for rainwater to run down on to, sit there and be absorbed into permeable materials, increasing moisture content, potentially putting them and adjacent absorbent materials at risk of frost damage, mould or rot.
    • External beading to windows and doors makes a relatively easy way in for burglars.
  • Solutions:
    • Avoid deeply recessed joints in masonry, flush joints will work better.
    • Plain rebated or tapered lapped weatherboarding is relatively less climbable.
    • Shiplap and rebated v-jointed boards could be avoided.
    • Diagonal boarded façade may offer a climbing challenge that cannot be turned down.
    • Internally glazed windows and doors keeps vulnerable beading out of reach by burglars.

BRAD R Physical infrastructure and network connection:

  • Problems:
    • Electricity and water or moisture vapour should not come into contacts with each other.
  • Solutions:
    • Absence of water or moisture vapour is a good thing in the presence of electricity.
    • Make sure all services penetrations of water/vapour proofing membranes are designed and installed competently.
    • Ensure conduits cannot become routes for air leakage, water and moisture vapour.

BRAD S Infrastructure for charging electric vehicles:

  • Problems:
    • Electricity and water or moisture vapour should never come into contacts with each other.
  • Solutions:
    • Absence of water or moisture vapour is a good thing in the presence of electricity.
    • Make sure all services penetrations of water/vapour proofing membranes are designed and installed competently.
    • Ensure conduits cannot become routes for air leakage, water and moisture vapour.

BRAD Z Embodied Energy

  • (Only a campaign so far, an essential part of Zero Carbon Future)

BRAD 7 Materials and workmanship:

  • Problems:
    • Long term housing insurers Housing Association Property Mutual (HAPM) & Construction data provider SPON published Component Life Manuals (CLM).
    • CLM are used to determine life expectancy, durability, failure modes and insurable life of construction methods and materials.
    • Part of their methodology CLMs marked-down materials and products that are not ‘Proper Materials’.
    • UK Government have hinted they may disband UKCA after manufacturers have spent 10s of thousands of pounds on them preparing for Brexit.
  • Solutions:
    • Always use ‘Proper Materials’ including:
      • BSI Kitemarked: UK and internationally.
      • British Board of Agrément (BBA) certified products: in construction in UK.
      • National or Euro Agrément products in Europe.
      • European Technical Assessment (ETA) products in Europe.
      • UK Technical Assessment (UKTA) apparently they exist, I have never come across one.
    • NB: Whilst CE marked or UKCA (post Brexit) marked products are listed under ‘Proper Materials’ they are only compliant with legal minimum requirements to be sold in EU or UK respectively; but may not be ‘fit for purpose’ in a project specification context.
      • Don’t let your legal department tell you not to specify above the legal minimum.
      • Specify for building competency.
      • Post-Brexit Government Procurement is no longer under EU Directives and scrutiny.
    • BSI Kitemarked products are made to comply fully with British Standards and factory procedures inspected for competency; that work well with Code of Practice (CoP) which works well with Building Regulations Approved Documents (BRAD) to make competent buildings.
    • BBA certified product or systems tend to break the rules of CoP and BRAD and through trial and error set their own rules and document them in the certificate; if these rules are followed by the designer and installer it will result in a competent installation.
    • ‘Police’ your specification by tender evaluation, contract administration, delivery ticket inspection and site inspection of materials and their packaging, to ensure any substitutions and surreptitious substitutions do not lower the quality of installed materials below the ‘Or Equivalent’ ‘Proper Materials’ threshold.

© GBE GBC GRC GBL NGS ASWS Brian Murphy aka BrianSpecMan ****
30th November 2023

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Brian Murphy aka BrianSpecMan BRM @ Build4 CAPEM Showroom

Brian Murphy aka BrianSpecMan BRM @ Build4 CAPEM Showroom

 

© GBE GBC GRC GBL NGS ASWS Brian Murphy aka BrianSpecMan ****
30th November 2023

About:

GBE Opinion

GBE State of the Industry

Sectors

GBE Greenwash

GBE CPD

GBE Jargon Buster

  • Violet (Jargon Buster) G#1583 N#1516

© GBE GBC GRC GBL NGS ASWS Brian Murphy aka BrianSpecMan ****
30th November 2023

GBE Performance Gap (Opinion) G#41216 End.

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