EWI to lower roof sloping along external wall. [Version ID #185]
Detail summary
Detail of junction of EWI to existing roof, either pitched or sloping along the external wall to be insulated. Applicable where existing roof tiling or other finish is to be retained meaning perimeter junction of EWI needs to be sealed and flashed along length.
Technical description
Section detail. EWI to lower roof. Pitched/sloping away from insulation. External woodfibre insulation used in conjunction with 400 - 200mm, rigid, external perimeter insulation suitable for use in a splash zone. Appropriate cap flashings and soakers to be used alongside mastic detail at junction with roof.
SUGGESTED INSTALLATION SEQUENCE:
1) Remove any existing projecting masonry/render from existing wall 2) Fix external wall insulation. 3) Fix supporting bracket. 4) Friction fit water resistant insulation in splash zone between external wall insulation and existing roof. 5) Fix cap flashings and soakers to base of EWI at existing roof. 6) Mastic seal edge. 7)Render up to flashing.
REFERENCE SPECIFICATION:
Perimeter insulation suitable for below ground use and drainage layer. To BS EN 13164. Rainwater drainage: please refer to approved document H, section H3, rainwater drainage for guidance. Stainless steel strip flashing to BS EN 10088-2 and BS EN ISO 9445-1 or -2.
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.
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.
Rolled lead sheet to BS EN 12588. Tolerance (by weight): ±5%. Colour marked for thickness.
Soakers and step flashings (slate or tile roofs): 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). Overlap to soaker upstands 65mm (min) cover. 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). Overlap to soaker upstands 85mm (min) cover. 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). Overlap to soaker upstands 65mm (min) cover. Lead wedges at every course. Length: 1500mm (max), end to end joint: laps 100mm (min). Overlap to soaker 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.
Step flashings with secret gutter. For step flashings: Length: 1500mm (max), end to end joint: laps 100mm (min). Overlap to soaker upstands 65mm (min). Fixing: lead wedges at every course. For Secret gutter lining: For step flashings: Length: 1500mm (max), end to end joint: laps 100mm (min). Overlap to soaker upstands 65mm (min). Fixing: Dressed into secret gutter. Welted edge at side to be tiled. Nailed top edge to each sheet. Bottom end dressed neatly into eaves gutter.
Step and cover flashing with secret gutter. Length: 1500mm (max), end to end joint: laps 100mm (min). Overlap to soaker upstands 85mm (min). Cover to roof: 150mm (min). Lead wedges at every course. Clipped at first 500mm (max) centres along free edge. For Secret gutter lining: lengths 1500mm (min). Upstand 65mm (min) above tiles. Fixing: ressed into secret gutter. Welted edge at side to be tiled. Nailed top edge to each sheet. Bottom end dressed neatly into eaves gutter.
Parts list
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External Wall Insulation (Woodfibre), rendered finish [EW01]
For use on solid and hard to treat cavity walls. 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
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External Insulation at roof abutment level [EW01]
Extruded Polystyrene (XPS) to BS EN 13164. Suitable for below ground conditions and for application of render. \ Thickness as external wall insulation. Depth: 600mm below internal floor level or to footings. Tight butt joints. \ Thermal conductivity: 0.033W/m2K. GWP<5.
BASF \ http://www.plasticsportal.net/wa/plasticsEU~en_GB/portal/show/content/literature/styrodur \ Reference: Styrodur 2800C.
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Cap flashing and soakers embedded into rigid insulation [RF09b]
H71b lead sheet flashings and weathering. Rolled lead sheet to BS EN 12588. Tolerance (by weight): ±5%. Colour marked for thickness. Soakers 1.50 to 1.75mm (code 3) lead sheet. \ Dressed up and bedded into new EWI. / Dressed over mini - gutter wall. / (Refer to Lead Sheet Asscoaition LSA publication 'Rolled Lead Sheet: The Complete Manual' \ 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). Overlap to soaker upstands 65mm (min) cover. Lead wedges at every course.
Contractor’s choice
Revisions
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Admin - 2015-04-29 12:09:29
DWG uploaded. EW01 roof abutment insulation amended to include "use in splash zone".
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Admin - 2015-03-27 16:34:43
Preview image and .pdf file updated.
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Admin - 2015-03-24 12:29:19
General formatting. Introduction expanded. Technical description expanded: approved document links added. Installation sequence revised. Parts list updated with suppliers links. Adhesive and mastic added to Parts list.
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Admin - 2015-03-24 12:27:09
General formatting. Introduction expanded. Technical description expanded: approved document links added. Installation sequence revised. Parts list updated with suppliers links.
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Admin - 2015-03-24 12:26:17
General formatting. Introduction expanded. Technical description expanded: approved document links added. Installation sequence revised. Parts list updated with suppliers links.
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Admin - 2015-03-13 12:18:28 [Displayed version]
Version 3. Introduction and technical description updated and expanded. Parts list added.
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Admin - 2015-02-27 16:41:26
Version 2 -Preview image updated
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Admin - 2015-02-27 16:39:29
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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