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Combination Adhered
A combination adhered system will typically consist of:
- A structural deck
- Loose laid vapour control layer
- Mechanically fastened thermal insulation
- Adhered Sarnafil G410-EL, Sarnafil G410-ELF or Sarnafil TG76-Felt membrane
The type of membrane chosen will generally be determined by aesthetic and budget considerations. Felt-backed membranes mask surface irregularities better than non felt-back versions, but the addition of the felt increases product cost slightly.
The vapour control layer is generally a polyethylene, such as EcoVap E or Sarnavap E, 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 suitable thermal insulation board for use in adhered systems must be selected from Sarnafil document Insulation Boards for use with Sarnafil Adhered System. In systems where a single point guarantee is required, SarnaTherm insulation must be used. The selected thermal insulation board is then attached to the substrate with SFT fasteners and SBIW-70x70 pressure plates, the quantity and position of which Sarnafil Ltd will determine by wind uplift calculation.
Finally, the membrane is adhered to the surface of the mechanically fastened thermal insulation board using either Sarnacol 2170 or Sarnacol 2142s (fleece-backed membrane only) adhesive. The mechanically fastened peel stop is installed at the perimeter, all penetrations and at direction changes. The inclusion of the peel stops at areas vulnerable to wind uplift minimises the risk of delamination.
Note:
In a roof refurbishment, the existing waterproofing system can often be used as the vapour control layer.
© 2006 Sarnafil Ltd. Legal Disclaimer
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