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Sarnabar Mechanically Fastened Roofing
The Sarnabar system typically consists of:
- A structural deck
- Loose laid vapour control layer
- Mechanically fastened thermal insulation
- Mechanically fastened Sarnafil S327-EL or Sarnafil TS77-E membrane
The Sarnabar system is also suitable for applications without thermal insulation, but either Sarnafil S327-ELF or a Sarnafelt separation/cushion layer will be required.
The vapour control layer is generally a polyethylene, such as EcoVap or Sarnavap, with all overlapping joints sealed with Sarnavap tape. If a bituminous vapour control layer is used, it must be fully adhered to the substrate with Sarnacol 2142s, synthetic cold bitumen or hot bitumen (if insurance permits the use of this method).
A thermal insulation board, meeting the requirements of BS 6229 : 1982 ‘Code of Practice for flat roofs with continuously supported coverings’, such as SarnaTherm, will be mechanically fastened through the vapour control layer to the substrate, using SBT tubes and SBF fasteners with a SBIW-70x70 pressure plate.
Finally, the membrane is loose laid and all overlapping joints are hot air welded (prior to the installation of the Sarnabars) at centres calculated by Sarnafil Ltd, to meet the wind uplift requirements of the project. The Sarnabars are mechanically fastened using SBT tubes and SBF fasteners, at fixing centres calculated by Sarnafil Ltd, prior to being covered with a 200mm wide strip of Sarnafil membrane hot air welded on both sides.
Notes:
- In a roof refurbishment, the existing waterproofing system can often be used as the vapour control layer.
- If Sarnafil S327-EL membrane is applied over bituminous membrane, a separation layer (such as Sarnafelt Type T) is required.
- If applied over an existing thermoplastic membrane, a separation layer (such as Sarnafelt Type A) is required.
- If the surface is rough, a cushion layer (such as Sarnafelt Type A, T, or S) is required.
- If Sarnafil S327-EL membrane is to be installed over an unfaced extruded or expanded polystyrene thermal insulation board, a separation layer of Sarnafil Glassmat 120 should be used.
© 2006 Sarnafil Ltd. Legal Disclaimer
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