EWI verge detail at flat roof [Version ID #148]

Author details

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Detail summary

EWI detail up external wall, to junction with and existing flat roof where no additional insulation has been added to roof buildup. EWI carried up beyond existing roof level to form parapet detail. Waterproofing membrane lapped under existing mastic roof trim carried over EWI. New stainless steel flashings to cap, glued to membrane.)

Technical description

Section detail. EWI to existing wall up to existing flat roof. Form verge. New flashing and membrane to BS EN 10088-2 and BS EN ISO 9445-1 or -2. with sealant to flashing to BS EN ISO 11600. Reference should be made to Approved Document H (draonage and waste disposal) http://www.planningportal.gov.uk/buildingregulations/approveddocuments/parth/

Membranes/Underlays: Butt jointed onto dry substrate, edges fixed with steel staples, or extra large head clout nails. Avoid tears and punctures when handling. Do not lay over eaves and drip/ step stainless steel underlaps. Keep dry and cover with stainless steel at the earliest opportunity.

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

  • External Wall Insulation (Woodfibre) System With Rendered Finish

    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

  • Stainless Steel Flashings

    Flashing at junction between flat roof verge and external wall insulation. To BS EN 10088-2 and BS EN ISO 9445-1 or -2. with sealant to flashing to BS EN ISO 11600. \ Austentic alloy grade 1.4301 (304). \ Thickness 0.5mm. \ Mill finished. Minimum lap as per drawing. \ Wedge fixed into joints, chases and damp proof course joints.

    Contractor choice

  • Airtightness works to ceiling

    Seal all ceilings and repair any cracks in plaster to ensure no air-leaks. Standard decorators caulk.

    Contractors choice


  1. Admin - 2015-04-29 11:24:36

    General formatting changes. DWG file updated.

  2. Admin - 2015-03-27 16:24:23

    Preview image and .pdf file updated.

  3. Admin - 2015-03-27 12:39:27

    General error removal. Codes amended so concurrent with drawing.

  4. Admin - 2015-03-23 16:16:20

    General re-formatting. Technical description expanded with installation sequence. Parts list expanded and parts added.

  5. Admin - 2015-03-23 16:15:37

    General re-formatting. Technical description expanded with installation sequence. Parts list expanded and parts added.

  6. Admin - 2015-03-13 15:48:10

    Technical description and parts list updated.

  7. Admin - 2015-03-11 15:52:05 [Displayed version]

    Parts list, introduction and technical description added/updated.

  8. Admin - 2015-02-27 12:56:18

    Version 1

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