EWI to lower roof sloping away from external wall
Detail summary
Detail for external wall insulation to the top of an existing sloping lower roof, projecting from an external wall to be insulated. For use where the existing flashing to the projecting roof is to be retained, but with new flashing over the junction with EWI and existing roof.
Detail also indicates junction between woodfibre insulation system and insulation suitable for splash zone. EWI system is cut to slope of lower/projecting roof and flashed over to prevent any gaps in insulation.
Technical description
Section detail. EWI junction to existing pitched roof, lower, sloping in direction away from external wall, roof finish to be retained. Junction between woodfibre insulation layer and XPS insulation. No airtightness works to existing ceiling below projecting roof.
Suggested Installation Sequence:
- Fix Woodfibre external wall insulation. Adhesive to side in contact with XPS insulation.
- Friction fit water resistant insulation in splash zone between external wall insulation and existing roof.
- Fix Stainless Steel flashing. Slot cut into XPS to take lip of flashing. Ensure watertightness.
- Render insulation up to flashing.
Reference Specification:
Guidance should be sought from Approved documents C, section 5 and 6; and Document H, sections 2 and 3 for rainwater drainage.
Perimeter insulation suitable for below ground use and drainage layer. To BS EN 13164. Stainless steel strip flashing to BS EN 10088-2 and BS EN ISO 9445-1 or -2.
Notes:
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 existing roof, to be agreed with contract administrator prior to work being undertaken. Prior to start on site inspect the form and condition of the roof structure; institute repairs and/ or additional works necessary to make the existing construction suitable to receive EWI system.
Services:
Rainwater pipes and waste water pipes to be moved to the outer face of insulation as standard, and swan-necked back into gullies where possible. Any work additional to this should be agreed in writing with the contract administrator.
Soil Pipes: An assessment of the condition of soil pipes should be undertaken prior to external wall insulation being undertaken. Drawing assumes soil pipes will remain in-situ. However in some circumstances in order to do this they will need to be replaced, and in others they will need to be moved. This is to be agreed in writing before start of work.
Parts list
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EWI(Woodfibre), with rendered finish [EW01]
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/ -
External Insulation at roof abutment level [EW01]
Extruded Polystyrene (XPS) suitable for below ground conditions/Use in splash zone, and for the application of render.
- Thickness: as EWI.
- Depth: Minimum 300mm above roof abutment level.
- Thermal conductivity: 0.033W/m2k. GWP: <5.
- Joints: Tight butt joints
BASF. Product Reference: Styrodur 2800C insulation.
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Woodfibre EWI adhesive [EW01]
Adhesive for use at joint between perimeter/ plinth insulation and external wall insulation.
Back to Earth. Tel: 01392 861763
Web: http://www.backtoearth.co.uk/
Product Reference: UdiSpecial Adhesive. -
Stainless Steel Apron Flashings to Lower Roof Abutments [EW01]
H75 stainless steel strip or sheet coverings and flashings to BS EN 10088-2 and BS EN ISO 9445-1 or 9445-2.
- Manufacturer: Contractor's Choice.
- Type: Austenitic alloy grade 1.4301 (304).
- Mill finished.
- Thickness 0.4mm.
- Minimum lap to roof covering: 150mm.
- Fixing into insulation to splash zone: Contractor's choice.
- Masonry joint sealant: High modulus elastic sealant, colour to match render.
Contractor’s choice.
Revisions
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Admin - 2015-04-29 12:13:24 [Displayed version]
Parts list updated. to include Back to Earth contact details for EW01. BASF contact links provided for insulation at roof abutment [EW01]. general formatting changes. DWG uploaded.
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Admin - 2015-03-27 16:35:44
Preview image and .pdf file updated.
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Admin - 2015-03-24 12:25:26
General re-formatting. Introduction revised and expanded. Technical description expanded with Approved document links and installation sequence. Parts link suppliers links added.
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Admin - 2015-03-13 12:23:22
Introduction and technical description updated. Parts list updated.
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Admin - 2015-02-27 16:50:04
Version 1
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For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
- Ease of understanding detail: Easy
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For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
- Ease of understanding detail: Easy
- Ease of sourcing materials: Easy
- Ease of sourcing skills: Easy
- Ease of implementation: Easy
- Overall cost: Low cost
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User name
For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
- Ease of understanding detail: Easy
- Ease of sourcing materials: Easy
- Ease of sourcing skills: Easy
- Ease of implementation: Easy
- Overall cost: Low cost
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For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us.
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