EWI to pitched roof with flashing at verge over insulation.
Detail summary
Detail for EWI up to an existing verge on a pitched roof. Where it is not possible to extend the existing roof verge over the insulation, a new Stainless steel mini-gutter is installed, at the junction between the roof verge and the new external wall insulation.
Technical description
Section detail. EWI to existing pitched roof verge, with EWI extending beyond. New flashing and verge guttering added to prevent water damage to EWI.
Reference Specification
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.
Natural slates to BS EN 12326-1 and -2. Battens, counterbattens and ridge/ hip fixing battens Timber species: To BS 5534, clause 4.12.1. Fasteners to BS 1202. All breathable membranes under Slating to be Agrément certified. Bitumen sheet to BS8747 Annex B.
Battens, counterbattens and ridge/ hip fixing battens Timber species: To BS 5534, clause 4.12.1. Fasteners to BS 1202. All breathable membranes under Slating to be Agrément certified. Bitumen sheet to BS8747 Annex B.
For all works to existing roofs refer to Approved document C (resistance to contaminants and moisture), with reference to Section 2, and section 6.
Reference should be made to Document H (drainage and waste disposal). Approved Document F (ventilation) should be referred to with regards to ventilation to existing roofs and over eaves ventilation. Document L1b should be referred when working on existing dwellings, with particular attention to sections 5 and 6 regarding material alterations. Document L2b should be referred to with existing buildings other than dwellings.
Lead sheet: Rolled lead sheet to BS EN 12588. Tolerance (by weight): ±5%. Colour marked for thickness.
Soakers and step flashings (slate or tile roofs): Lead Soakers:
- Length: Slate/tile gauge + lap + 25mm.
- Upstand: 75mm (min)
- Underlap: 100mm (min).
Lead step flashings:
- Length: 1500mm (max).
- End to end joint: laps 100mm (min).
- Cover: overlap to soaker upstands 65mm (min) cover. Lead wedges at every course.
- Fixing: lead wedges at every course.
Step and cover flashings (single lap tile roofs) in sheltered/ moderate exposure locations.
- Length: 1500mm (max).
- End to end joint: laps 100mm (min).
- Upstands 85mm (min).
- Fixing: Lead wedges at every course. Clipped at 500mm (max) centres along free edge.
Single step and cover flashings (single lap tile roofs) in exposed locations.
- End to end joint: laps 50mm (min).
- Cover: Overlap to soaker upstands 65mm (min) cover.
- Fixing: Lead wedges at every step.
Lead cover flashings:
- Length: 1500mm (max).
- End to end joint: laps 100mm (min).
- Upstands: 85mm (min).
- Cover to roof: 150mm (min) and over first tile corrugation.
- Fixing: turned over head of tiles. Clipped at first 500mm (max) centres along free edge. Upstand plugged and screwed to abutment in top third of each length only.
Notes
Care should be taken to ensure air-tightness. Seal all service penetrations. Lap and tape all membranes.
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 verge, to be agreed with contract administrator prior to work being undertaken. Prior to start on site inspect: form and condition of the existing roof and verge structure; institute repairs and/ or additional works necessary to make the existing construction suitable to receive EWI system.
Existing services
Rainwater Pipes and Waste Water Drainage: Rainwater pipes and waste water pipes will be moved to the outer face of insulation as standard, and swan-necked back into gulleys where possible. Any work additional to this should be agreed in writing with the contract administrator.
Windows and doors: Where windows and doors are to be replaced in insulation please refer to contract/window schedules for details. Where windows and doors are to be retained in insulation please refer to relevant detail drawings to show reveal insulation and cills.
Parts list
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Stainless Steel Flashings [RF09a]
To BS EN 10088-2 and BS EN ISO 9445-1 or -2. with sealant to flashing to BS EN ISO 11600.
- Manufacturer: Contractor's Choice
- Austenitic alloy grade 1.4301 (304).
- Thickness: 0.4 mm.
- Finish: Mill finished.
- Minimum lap to roof covering: As drawing.
- Fixing: Wedge fixed into joint chases and DPC joints.
Contractor's choice
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H71b Lead Sheet Soakers [RF09C]
H71b lead sheet flashings and weathering. Rolled lead sheet to BS EN 12588.
- Soakers: 1.50 to 1.75mm (code 3) lead sheet.
- installation: Dressed over mini-gutter wall. (Refer to Lead Sheet Asscoaition LSA publication 'Rolled Lead Sheet: The Complete Manual'. \ To BS EN 12588. Tolerance (by weight): ±5%. Colour marked for thickness.
Contractor's choice.
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Softwood Eaves Fascia Board [RF09b]
- Species:European White wood to appearance class BS EN 942, clas J30.
- Size: to suit existing.
- Treatment: required.
- Fasteners: Stainless steel nails at fixing centres determined by contractor.
Contractor's choice.
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EWI (Woodfibre) system, rendered finish [EW01]
Composite woodfibre board for use on solid and hard to treat cavity walls.
- Insulation back board: 100mm UdiTherm SK.
- Insulation top board: 100mm 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/
Revisions
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Admin - 2015-04-29 14:56:32 [Displayed version]
DWG file uploaded. General formatting amendments.
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Admin - 2015-04-29 14:54:27
DWG file uploaded. General formatting amendments.
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Admin - 2015-03-27 17:01:00
Preview image and .pdf file updated.
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Admin - 2015-03-24 18:11:49
General formatting. Introduction expanded. Technical description approved doc links expanded. Notes added. Parts list updated with suppliers links.
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Admin - 2015-03-13 15:45:05
Technical description updated. Parts list updated with codes and expanded.
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Admin - 2015-03-06 13:14:46
Version 2. Category change
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Admin - 2015-03-06 13:11:23
First version
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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.
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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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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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