EWI to New Manchester Window

Author details

Original Author:Admin Organisation:Retrofit Pattern Book

Detail summary

Detail for a triple glazed replacement Manchester window and associated junction with EWI to wall above. Designed to help preserve the character of an existing Manchester window while reducing thermal bridging and improving air-tightness.

Technical description

Section detail. EWI to replacement Manchester Window, sloping, retrofit and replace existing window and associated windows or patio doors.

Reference Specification:

British Standards- please ensure:

  • Sloping and vertical patent glazing: to BS 5516-1.
  • Access and openings: In accordance with BS 8213-1
  • Insulating glass units to BS 5713 and Kitemark certified or to BS EN 1279.
  • Perimeter seals: Resistant to UV light degradation on exposed edges. Edge seal strength: To BS EN 1279-4.
  • Timber windows to BS 644, With Timber members for purpose made windows to BS EN 942.
  • Where safety glazing used in door leaves, standard to BS 6262-4 and to BS 6206 for safety plastics and BS EN 12600 for safety glass.

Installation of fire resisting and/ or smoke control doors/doorsets: In accordance with instructions supplied with the product conformity certificate, test report or engineering assessment.

Gaps between frames and supporting construction: filled as necessary in accordance with requirements for certification and/or door/ doorset manufacturer's instructions.

For fire door lining and escape route guidence, refer to: Approved document B (fire safety) for guidance for both dwellings and non-dwellings for existing buildings.

Approved Document F (ventilation) should be referred to with regards to ventilation as part of window or door construction.

Documents K (protection from falling) and Document M (Access to and use of buildings) should also be referred if installing external patio doors as part of window works.

Care should be taken during the installation to ensure the continuity of insulation and air-tightness at the junction between window, existing wall and external wall insulation.

Parts list

  • Proprietary triple-glazed patent glazing system [GD04]

    Triple glazed argon filled insulated glazing units.

    • Size: to suit glazing bar centres and general arrangement, bottom overhang not less than 50 mm.
    • Outer pane: 6 mm clear toughened glass
    • Inner pane: 6 mm clear low emissivity toughened glass

    Contractor's choice.

  • Aluminium Glazing Bars and Flashing [GD04]

    Box section inverted glazing bars.

    • Finish as delivered: Mill finished.
    • Size: Section and spacing to contractors choice.
    • Fixing: Stainless steel fasteners with fixing caps to prevent unauthorised removal.
    • Flashing detail: Aluminimum head flashing

    Contractor's choice

  • H71b Lead Sheet Apron Flashing to patent glazing [GD04]

    Rolled lead sheet.

    • Thickness: 1.75-2mm.
    • Length: 1500mm (max) with 220mm cover to glazing.
    • Fixing: Lead wedges fixed into bed joint, clips to bottom edge at laps and 500mm centres. Stainless steel clips terne coated where exposed to view.
    • Spacing: as contractors choice to suit exposure.
    • Clip fixing: Plugged and screwed to vertical abutment through two (minimum) pre-drilled holes

    Contractor's choice

  • EWI (Woodfibre) System, Rendered Finish [EW01a]

    Composite woodfibre board for use on solid and hard to treat cavity walls.

    • Insulation back board: UdiTherm SK.
    • Insulation top board: Diffutherm NF (T&G, renderable).
    • Thermal conductivity: 0.045W/m2K. GWP 0.
    • 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.
    • Fixing: Fixed mechanically to substrate in accordance with manufacturers recommendations.
    • Render/carrier: to manufacturers standard.
    • Render: Udi Perl
    • Decorative finish: tbc
    • System guarantee: 25 years - ECO compliant insurances and guarantees.
    • System Certification : ETAG

    Unger-Diffutherm. Product Reference: UdiFRONT.
    Supplied by Back To Earth: Tel: 01392 861763
    Web: http://www.backtoearth.co.uk/

  • New timber triple or glazed window / patio doorset. [GD01/10/11]

    • Type: Triple glazed Timber Patio Doorset.
    • Target U-value: 1.1 W/m2K.
    • Size: As existing.
    • Configuration: Inward opening, double.
    • Security: Locking with security measures to Secured by Design standard
    • Material: FSC 100% Redwood.
    • Finishes:
    • Interior : Clear timber.
    • Exterior : Painted or stained factory finish.
    • Drip rail: Aluminium.
    • Air-tight installation: Install windows to achieve maximum air-tightness, using appropriate air-tight tape and sealants at all junctions and potential air-leakage points. (Expanding PU foam will not be sufficient to achieve adequate air-tightness).

    Green Building store
    Tel: 01484 461705
    Web: http://www.greenbuildingstore.co.uk/
    Product Reference: Ecocontract Secondary Doorset.

  • Threshold/ Cill (patio doors only) [GD11]

    Hardwood with mobility threshold seal.

    Contractor's choice or to Door Manufacturers detail.

  • Sealant To External Door Frames (Patio doors only) [GD11]

    Silicone sealant.

    • Colour to contractors choice.
    • convex profile.

    Contractors choice.

  • EWI for ground level/within splash zone [EW01a]

    Extruded Polystyrene (XPS) suitable for splash zone and for application of render.

    • Thickness: as EWI.
    • Depth: Minimum 300mm below roof level.
    • Thermal conductivity: 0.033W/m2k. GWP: <5.
    • Joints: Tight butt joints

    BASF. Product Reference: Styrodur 2800C.

  • Woodfibre EWI adhesive [EW01]

    Adhesive for use at joint between perimeter/ plinth insulation and external wall insulation.

    As EWI manufacturers recommendation; Or:
    Back to Earth. Tel: 01392 861763
    Product Reference: UdiSpecial Adhesive.


  1. Admin - 2015-04-29 10:29:00 [Displayed version]

    EW01a external insulation part amended.

  2. Admin - 2015-04-29 08:42:02

    DWG file uploaded. Approved document embedded links added for docs K & M. Parts list amended to include new contact details for Ecocontract doors, Sytrodur and Back to Earth. Formatting changes

  3. Admin - 2015-04-29 08:36:08

    DWG file uploaded.

  4. Admin - 2015-03-27 17:36:53

    Preview image and .pdf file updated.

  5. Admin - 2015-03-27 14:53:34

    XPs and adhesive added to parts list. Codes updated to match drawing.

  6. Admin - 2015-03-19 18:18:14

    General formatting and error correction.

  7. Admin - 2015-03-19 18:17:40

    General formatting and error correction.

  8. Admin - 2015-03-19 18:15:07

    General formatting and error correction.

  9. Admin - 2015-03-13 17:46:46

    Technical description updated. Parts list revised with codes.

  10. Admin - 2015-03-12 17:27:35

    pdf/dwg file updated to latest revision with lineweights and colour blocks

  11. Admin - 2015-03-11 17:29:57

    Parts list updated with relevant codes

  12. Admin - 2015-03-11 16:36:55

    Technical description updated. Preview image and dwg file updated to latest revision.

  13. Admin - 2015-03-10 11:07:45

    Parts list updated, technical summary and intro updated, and title revised

  14. Admin - 2015-03-10 11:06:53

    First version

  15. Admin - 2015-03-10 11:02:09

    First Version

  16. Admin - 2015-02-27 12:10:40

    Version 2- .dwg file updated

  17. Admin - 2015-02-26 11:02:22

    Added preview image

  18. Admin - 2015-02-26 10:55:36

    Full second version - text edited

  19. Admin - 2015-02-26 10:43:43

    First version

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