EWI- window to eaves with soffit [Version ID #165]

Author details

Original Author:Admin Organisation:

Detail summary

Detail for EWI designed to deal with potential cold bridge at eaves - where loft or roof insulation meets cavity or other wall insulation. In this case a standard overhanging soffit above a window to be replaced. New EWI to join to overhanging eaves insulation directly above window.

Technical description

Section detail. EWI to existing wall above existing window to be replaced. Existing eaves soffit board removed, new phenolic foam insulation above to join to EWI. Window replacement with triple glazed window with new timber frame.

All new replacement timber windows to BS 644, operation and strength characteristics to BS 6375-2. All timber members in windows to BS EN 942. Glazing beads clear finish to Class J2.

Tiling work: Clay tiles to BS EN 1304/ concrete (non interlocking) to BS EN 490. All battens/counterbattens and ridge/hip fixing battens to be timber species to BS 5534, Clause 4.12.1. All fasteners to BS 1202 as appropriate to fastener type

Existing guttering to be replaced/reinstated to BS EN 607, and BS EN 1462, Kitemark certified, clauses 3–7 and National Annexes. Collection and distribution of rainwater: Complete, and without leakage or noise nuisance. Reference should be made to Approved Document H (drainage and waste disposal) and Document F (ventilation)

Care should be taken to ensure air-tightness. Seal all service penetrations through EWI and existing wall. Lap and tape all membranes around edges of EWI system.

All insulation to be continuous to avoid thermal bridging.

Preparation of external wall: Remove any existing loose material and prepare in accordance with manufacturer's requirements.

Any alterations to drainage and other fixtures, or work to prepare the substrate, to be agreed with contract administrator prior to work being undertaken. Prior to start on site inspect the form and condition of the structural substrate; institute repairs and/ or additional works necessary to make the substrate suitable to receive EWI system.

Parts list

  • Loose laid loft insulation [FAB L01]

    Flexible, formaldehyde-free, glass mineral wool. 85% (minimum) recycled content to BS EN ISO 14021. \ Installation: Insulation cover should be even and continuous to eaves. Ensure insulation meets any eaves insulation and/or internal wall insulation to prevent cold bridge at eaves without blocking any ventilation paths required to loft space/ roof space.

    Knauf. \ http://www.knaufinsulation.co.uk/#axzz3UBRLTJfC \ Reference: Earthwool loft roll 40

  • Insulation to Eaves (rigid) [RF06b]

    Phenolic foam. \ Thickness: 50mm. Width: cut to suit rafters. Length: 750mm PLUS distance to eaves board OR 200mm (whichever is smaller). \ Thermal conductivity: 0.023W/m2k. \ Installation: Continuous with roof insulation, no gaps, to avoid cold bridging. Friction fit between rafters from inside loft, being careful not to damage existing roof membrane or structure or block existing ventilation paths.

    Contractors choice

  • New Timber frame, triple-glazed window to BS 644 [GD01]

    Eco-Contract Ultra Outward Opening Casement Windows.\ Thermal Performance (overall u-value) : 0.79W/m2K.\ Air-tight Size: As schematic.\ Opening Pattern/ Configuration : As existing (unless otherwise stated on schematic).\ Sash/Frame Material: FSC 100% Redwood.\ Drip Rail : Aluminium. \ Finish - Interior: Factory finished paint/varnish system.\ Finish - Exterior: Factory finished paint/varnish system. \ Glazing Unit : Triple, Argon Fill, 44mm. \ Glazing Type: as standard triple glazed unless stated: Light transmission : 72%. \ Solar factor (g): 52%. \ Handle Type: Manufacturer's standard, factory fitted. \ Security: Secured by Design.\ Accessories: Egress Hinges and Child Safety Restrictors. \ Guarantees: Manufacturer's standard.

    Manufacturer : Green Building Store. \ www.greenbuildingstore.co.uk \ Tel : +44 (0)1484 461705. \ Reference : Eco-Contract Ultra Outward Opening Casement Windows

  • External Wall Insulation (Woodfibre), rendered finish [EW01]

    For use on solid and hard to treat cavity walls. Composite woodfibre board. UdiTherm SK back board, Diffutherm NF (T&G, renderable) top board. \ Fixed mechanically to substrate in accordance with manufacturers recommendations. \ Base Coat - levelling on substrate: 90% contact required around edge of boards between board and substrate to prevent thermal bypass. If substrate is very uneven, use base-coat material around edge of board to achieve contact. \ Thermal conductivity: 0.045W/m2K. GWP 0.

    Unger \ www.unger-diffutherm.de \ Reference: UdiFRONT. \ Render: UDI Perl

Revisions

  1. Admin - 2015-04-29 09:51:37

    DWG file uploaded. Back To Earth contact details added to parts list for EW01. General formatting changes. EW01 part added.

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  2. Admin - 2015-04-29 09:48:25

    DWG file uploaded. Back To Earth contact details added to parts list for EW01. General formatting changes.

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  3. Admin - 2015-04-22 14:27:14

    Pdf file updated as per latest revisions

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  4. Admin - 2015-03-27 16:19:27

    Preview image and .pdf file updated.

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  5. Admin - 2015-03-27 12:01:09

    Technical description updated for air seal tape location. Insect screen added to parts list. EWI accessories added to parts list.

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  6. Admin - 2015-03-23 14:41:57

    General Error removal

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  7. Admin - 2015-03-23 14:26:29

    General formatting. Technical description added and expanded with detailed installation guidence and approved document links. Parts list updated with links,

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  8. Admin - 2015-03-13 18:13:13

    Technical description and parts list updated.

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  9. Admin - 2015-03-12 15:14:07 [Displayed version]

    Version 7. Technical description updated

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  10. Admin - 2015-03-12 14:58:38

    Version 6. Title updated,description and technical description updated and expanded. BS and Approved doc information added. Parts list added. Preview image and pdf file updated with revised linetype colours /line-weights.

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  11. Admin - 2015-03-03 14:52:53

    Preview image updated.

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  12. Admin - 2015-03-03 14:50:18

    Preview image updated. Parts list added.

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  13. Admin - 2015-02-27 12:19:01

    Version 2- title updated and .dwg file updated

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  14. Admin - 2015-02-26 15:27:09

    Second version- title changed to indicate window to soffit, rather than eaves.

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  15. Admin - 2015-02-26 15:15:55

    First Version

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