
L10 Windows Rooflights Screens Louvres Checklist
About:
Index:
Problems:
- Thermal bridging around windows
- Air leakiness around windows
- (see GBE Robust Specification P14)
- Thermal discomfort due to poor U value windows makes a well insulated building fail to meet expectations
- Excessive heat loss through windows compared to opaque building fabric
- (See U Values to Energy consumption to Carbon GBE Calculator)
Misunderstandings:
- Robust Details do not refer to durable tough details they refer to competent acoustic details that may fall short on other performance requirements.
- A passivhaus window does not automatically perform as well as designed if installed incorrectly or misaligned with the insulation in the wall
Solutions:
- Competent detailing (not necessarily robust details)
- Correct placement of windows in relationship to insulation in surrounding walls
- Passivhaus windows can eliminate cold down drafts and cold feet
- Avoid placing radiators under windows and on inside face of external walls
- Spend us much as you can on high performance windows
Consider:
- ‘Fabric First’ & ‘Build tight – Ventilate right’
- Highest performance windows you can afford,
- to reduce fuel demand (during heating season) over life of building
- Many Scandinavian manufacturers offer high specification at good price,
- not many UK manufacturers can compete, a few exceptions.
- Trickle vents controllable by occupant, visible and easy to use without risk of jamming
- Internal temperature of glass needs to be as close to the temperature of the wall
- (17-18 degrees C) for thermal comfort
- U values of 0.8 to 0.5 W/m2.K should achieve these temperatures
- Double and Triple glazing
- U Values of 1.0 to 0.5 W/m2.K are achievable
- Use Double Glazed Sealed Units to BS EN 1279-2 and BSI Kitemarked
- Use Low E (Emissivity) glass generally
- (to minimize heat loss by reflecting it back in)
- Use Argon, Pentane or CO2in sealed units
- (but be aware of the high environmental impact: See Bath ICE Database)
- Exclusion of UV light, using PVB interlayer in laminated glass
- (to reduce fading of objects inside)
- Permitting UV Light: for plant and food growing green houses
- Co-ordinate window and door opening with brick sizes and/or blocks modules to minimize cutting waste
- FSC approved timber sources and timber based materials See Z10
- Timber: Hardwood, Heartwood of softwood, Slow grown timber, reclaimed timber
- Uncoated recycled aluminium
- (but no coating reduces component life marginally)
NEW WOOD WINDOWS FROM UK MANUFACTURERS
- Choose local or FSC certified timber.
- Choose High performance windows with manual control trickle vents
- Choose from the British Woodwork Federation BWF’s Timber Window Accreditation TWA Scheme: Manufacturers, Suppliers and Installers.
- http://www.bwf.org.uk
- Get them fully finished in the factory on all faces, but avoid oil paints, choose microporous high build paints or stains
- Consider aluminium sill and bottom beads for durability in the most vulnerable locations.
- Choose BBA Certified and/or BSI Kitemarked windows
- Choose with BSI Kitemark Double Glazed Sealed Units
- Choose Windows with Secure by Design Accreditation
NEW WINDOWS FROM EU MANUFACTURERS
- Scandinavian and east European windows: are usually high performance compared to many UK makes.
Avoid:
- Excessive glazing on north face (heat loss and thermal discomfort in winter)
- Excessive glazing on any face (heat loss and thermal discomfort in winter)
- Excessive glazing on south and west faces (heat gains in summer unless it is managed and exploited)
- Single glazing: higher chance of condensation on inner face
- Double Glazed Sealed Units only offering U Value between 1.0 and 2.0 W/m2.K
- Indonesian Hardwood
- Most is reported to be illegally logged: destroys forests, communities and habitation
- CCA (Copper Chrome Arsenic) Treated softwood, See Z12
- Powder coated aluminium (hazardous residue or emissions when recycled)
- Primed timber windows being installed and then painted insitu, leaving vulnerable absorbent timber against potentially wet masonry.
- Apply full paint scheme to ALL faces in the factory.
- Virgin plastics See Z50
- PVC See Z50
- Give yourself and the fire fighters a better chance of survival in a fire
- Some Responsible Social Landlords have had enough bad experience to refuse to use PVC windows.
- Some RSL have maintenance regimes in place to wash PVC windows inside and out every 3 months so they have a chance to check for failing Ironmongery.
- They will also check for pinking or yellowing of the frames.
- Dulux created a paint specifically for painting PVC windows, I wonder why?
- 25 year life is optimistic for PVC windows, Ironmongery fails sooner if not steel reinforced sections.
Minimise:
- Use of virgin aluminium in window frames
- Use of PVC in all applications
- Use of preservatives in timber frame windows
Substitute:
- GRP Pultruded faced composite timber for:
- aluminium faced composite timber window frames
- PVC windows
Health:
- Long life powder coated or anodized aluminium in preference to painted metalwork
Wellbeing:
- Don’t ignore the feel good factor of seeing and touching timber
Safety:
Precautionary principle:
Resource Efficiency:
Reduce:
- Use of virgin aluminium in window frames
Reclaim:
- Reclaimed wooden windows
- Web Portal: Salvo Ltd.
Reuse:
- Reclaimed windows
Repairing Windows:
- Repair PVC windows rather than remove and landfilling them.
Refurbishing Windows
- See C51
- See Refurbishment Checklist L10
Recycle:
- Use recycled aluminium in preference to virgin aluminium, significant reduction in energy consumed and potentially CO2 generated
Recover:
- Do not incinerate:
- PVC windows high risk of Dioxin release to the atmosphere (See Trashed Film/Video)
- Painted wood windows
- Preservative treated wood windows
- Do not burn off coatings on aluminium windows
- Ensure emmissions to air are controlled
Waste Issues:
- WRAP guide on dismantling PVC windows to segregate waste
Waste Catagory:
- Window: Mixed waste
- Double glazed sealed units: Mixed waste
- Single glass: Inert
Waste statistics:
Waste minimization:
- Measure the openings accurately and forward the survey information before manufacture
End of Life options:
Hazardous waste & Deleterious Substances:
Design for recycling:
- avoid coatings as they create problematic expensive hazardous waste or emissions when recycling aluminium
- e.g. PPC Polysester Powder Coating and PVF2 Poly Vinyl Fluoride Coating
- Anodising is a chemical oxidation process generating an oxide of aluminium
- Anodised aluminium generates less problematic waste when recycled
- Mill finish is best for recycling but not everybody likes the oxides that form on aluminium
- Mill finish aluminium may have a marginally shorter life than coated aluminium
Appropriateness:
- Passivhaus windows in Passivhaus buildings
- Insulated, airtight weather resistant gap filling between window and surround
- Airtightness membranes designed for window perimeters and adjacent materials
- See NGS ROBUST SPECIFICATION P14
Competence:
- Align windows with the insulation in the surrounding wall or link them if they do not align
- Thermal bridges can seriously reduce the performance of the window
- A well placed poor performing window can be better than a badly placed Passivhaus window
- Choose BBA Certified and/or BSI Kitemarked windows
- Choose with BSI Kitemark Double Glazed Sealed Units
- Choose Windows with Secure by Design Accreditation
- Choose Windows with TWAS accreditation or equivalent
- Choose Windows with Passivhaus accreditation or equivalent
- Get them fully finished in the factory on all faces, but avoid oil paints, choose microporous high build paints or stains
- Always use an approved accredited or manufacturer trained installer
Effectiveness:
- In wood windows consider aluminium sill and bottom beads for durability in the most vulnerable locations.
Yardstick:
Maintenance issue:
- Anodized or coated aluminium give a long life but the guarantee relies upon a regular cleaning regime
- Painted and stain timber have a relatively short life between recoating
- Stains that can accept overcoating with more of the same and at worst needs sanding down; are easier to maintain than paint that may need to be removed or at least sanded down to accept over-coating
Industry Initiatives:
RecoVinyl:
- An EU fund for recycling extruded rigid PVC from window and other waste exists and a number of waste handlers are engaged in the scheme in the UK.
- Only one window manufacturer was involved in RecoVinyl so most are not using recycled content in their frames
- Most of the PVC that is recycled goes to make something other than windows, this does not make the windows any better
- (despite BRE Green Guide to Specification)
- Use of virgin PVC sheath over recycled PVC is adopted
- Use of recycled PVC in the core of a window section may not be a clever solution because the best PVC windows are steel reinforced in the core of the section
Information sources:
ARTICLES: (on GreenSpec)
- Window Materials
- Wood paints
- Wood preservation
- Glass:
- Ventilation:
BIBLIOGRAPHY:
- BedZED BioRegional Guide
© GBE NGS ASWS BrianSpecMan aka Brian Murphy
16th December 2012 – 20th February 2017
L10 Windows Rooflights Screens Louvres Checklist
Images:
GBE CPD
GBS Green Building Specification
P14 Air/wind tightness systems
Robust Specification Work Section
- P14 RSWS Airtghtnss A15 BRM 060414 doc
Robust Specification Guidance Notes
- P14_RSG_Airtightnss_A03_BRM_091212.doc
If you wish to reproduce images, feel free, but please acknowledge the source.
© GBE NGS ASWS BrianSpecMan aka Brian Murphy
29th July 2014 – 20th February 2017
L10 Windows Rooflights Screens Louvres Checklist
See Also:
GBE Compare
GBE Jargon Buster
- Air/Wind Tightness (Jargon Buster Theme) N#1391
- Timber (Jargon Buster Theme) N#1462
- BBA
- BSI
- BRE
- BWF
- DGSU
- FSC
- GGtS
- PVC
- PVCu
- TGSU
- TWAS
- UPVC
- BSI Kitemark
- BRE Green Guide to Specification (GGtS)
- British Booard of Agrement (BBA)
- Composite Window
- Double Glazed Sealed Unit (DGSU)
- High build stain
- Micro porous paint or stain
- Passivhaus
- Polyvinyl Chloride (PVC)
NGS CPD
- L10 Windows
NGS CHECKLIST
New Build
- L10 Windows
- L40 Glass and Glazing
- M60 Paint/Clear finishes
- P12 Ironmongery
- P14 Air/Wind Tightness Systems
- Z10 Purpose Made Joinery
- Z20 Fixings/Adhesives
- Z22 Sealants
Refurbishment
- C50 Repairing/Renovating/Conserving metal
- C51 Repairing/Renovating/Conserving timber
NGS LINKS
- FSC UK
- BSI
- BWF TWAS
- Secured by Design
NGS MANUFACTURERS
NGS PRODUCTS
NGS MATERIALS
NGS SYSTEMS
NGS ELEMENTAL ASSEMBLIES
- NG BEST
- NGS BEACON
NGS CALCULATOR
- U Values to Energy consumption to CO2
- Embodied Energy & Embodied Carbon
GBE Datasets
- GBE Timber Species Schedule N#1351
- Bath Uni ICE Database
GBE Jargon Buster
- ICE Database (Jargon Buster) G#1018 N#1037
GBE CAD
- 2D and 3D SketchUp Product files
- SketchUp files of Construction Sections
GBS Green Building Specification
Robust Specification Work Section
Robust Specification Guidance Notes
GBE Projects
© GBE NGS ASWS BrianSpecMan aka Brian Murphy
16th December 2012 – 20th February 2017