EWI to Existing Parapet Eaves [Version ID #72]

Author details

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Detail summary

Section detail for external wall insulation to existing parapet eaves.

Insulation designed to deal with potential cold bridge at eaves: where loft or roof insulation meets external wall insulation with a limited overhang at eaves so integral gutter required.

Technical description

Junction of EWI to insulation at existing parapet eaves. EWI cut to form new parapet for new gutter installed as part of works. New insulation and membranes to existing roof.

Installation : Carefully remove minimum 750mm of tiles or slates, putting to one side for reuse. Note positions of existing roofing battens. Remove roofing battens to at least 600mm up the roof from the existing eaves. Roll existing membrane back but do not cut. Insert rigid insulation between rafters, allowing at least 125mm from the edge of insulation board to the next batten position up the roof. Install breathable membrane/ roof underlay approx 500mm up roof slope from front edge of EWI. Pin in place to rafters with galvanised clouts at upper edge. Dress over EWI outer layer so as not to protrude beyond the front face. Insert stainless steel pressing over the top of the breather membrane/ roof underlay and EWI as shown on drawing. Fix in place with self drilling fixings to every third rafter at inner upper edge. Roll original membrane back over new stainless gutter to lap new gutter by 200mm. If required replace roofing battens in original locations up to approx 600mm above bottom edge of gutter. Dress the existing membrane over this reinstalled batten. Insert last batten at approx 350mm up from the edge of the gutter. Install polycarbonate vent strip as shown in drawing, pinned in place to relevant batten. Roll the original membrane over the top of the polycarbonate vent strip.Replace slates/tiles, dressing last slate/tile so as to be just below the upper edge of the gutter.

Parts list

  • Insulation to Eaves (rigid)

    Phenolic Foam. / Thermal conductivity: 0.023W/m2k. / Thickness: 50mm. / Width: cut to suit rafters. / Installation: Continuous with roof insulation, no gaps, to avoid cold bridging. Friction fit between rafters.

    Contractors choice

  • Breather Membrane/ Roof-underlay

    Installation: Sealed to insulation to eaves and dressed to drainage point at the end of each run of guttering to allow water to exit construction.

    Green Building Store / Reference: Solitex UM

  • Stainless steel gutter system

    Profile: As drawing. / Gauge: 1.2mm minimum. / Joining: Joins to be avoided where possible. If required must be fully welded and tested. Could be glued and blind riveted subject to approval. / Size: Contractor's choice - to suit existing roof dimensions and cover depth of external wall insulation. / Ensure provides adequate capacity for rainwater discharge from roof. / Finish As Delivered: Self Finished Stainless Steel Grade 304. / Setting Out: To falls. / Fasteners: As manufacturer's recommendations. / Accessories: Welded stop ends. / Testing: Test on completion.

    Contractors choice


  1. Admin - 2015-03-27 16:21:59

    Preview image and .pdf file updated.

  2. Admin - 2015-03-27 12:26:20

    Woodfibre EWI added to parts list. Air sealing to ceiling added to parts list. codes amended to match drawing.

  3. Admin - 2015-03-23 15:02:08

    General formatting. Technical description updated and installation sequence revised. Parts list updated with codes and suppliers links.

  4. Admin - 2015-03-12 15:58:51

    Intro and technical description updated and expanded. BS and Approved doc information added. Parts list added.

  5. Admin - 2015-03-03 15:12:57 [Displayed version]

    Preview image updated. Parts list added.

  6. Admin - 2015-02-26 15:36:58

    First Version

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