G410-EL Ballasted Roof System - Sarnavap 500E & S-Felt T 300

PVC-P single-ply membrane for adhered and ballasted warm roofs.

System includes:

• Stone ballast/precast concrete flag surface protection (supplied by others).

• S-Felt T 300 upper protective layer.

• Sarnafil G410-EL waterproof membrane.

• SarnaTherm G insulation.

• Sarnavap 500E vapour control layer.

- Upper protective layer:

A separation, levelling and protection layer made of polyester (PES).

- Waterproof membrane:

Sarnafil G membranes are manufactured using a state of the art extrusion coating process that eliminates shrinkage and plastic memory and produces a dynamically stable membrane. In the coating process, a glass fibre carrier is coated on both sides with liquid Plastisol, prior to the application of a lacquer coating on the upper surface and laser marking of the membrane surface for identification. The unique lacquer coating eliminates the need for biocides, provides the membrane with an easy to clean surface and prolongs the life of the membrane by reducing plasticiser loss.

The process enables between 2% and 5% of recycled material to be used in the production of new membranes.

- Insulation:

Rigid polyisocyanurate foam insulation boards to BS EN 13166; with mineral tissue facing. Available in uniform thickness or tapered.

- Vapour control layer:

A 0.15 mm thick, polyethylene based, vapour control layer. Sarnavap 500E is manufactured from low density polyethylene, blended to produce a vapour control layer that is flexible when cold, resistant to chemicals and ageing and rot proof. It is suitable for use in most mechanically fastened systems using the Sarnafil PVC membranes only. Not suitable for high humidity applications or under green roofs.

Performance:

Certified by BBA, in their opinion, to have a "life expectancy in excess of 40 years" for exposed applications, with periodic maintenance as stated below.

A planned maintenance cycle, including inspections by the Certificate holder at minimum intervals of five years, should be introduced if an extended service life is required. The Certificate holder can advise on methods of extending the service life. This could include the use of thicker membranes, specific maintenance requirements or localised replacement and repair.

Should the maintenance cycle not be followed Sarnafil G/S membranes have been given, by the BBA in their opinion, a life expectancy of "in excess of 35 years".

Installation:

- Upper protective layer:

Loose laid according to the valid installation instructions for Sarnafil®.

If necessary, S-Felt T 300 can be tacked to the substrate with Sarnacol® 2170 or Sarnacol® 2172. Adjoining sheets must overlap at least 100 mm.

- Waterproof membrane:

In warm ballasted applications the G410-EL membrane is loose laid, with all overlapping joints hot air welded prior to the application of a protection/ filter fleece and the chosen ballast system.

Installation is carried out by Sarnafil trained contractors.

- Insulation:

SarnaTherm G can be attached to the substrate (deck or suitable vapour control layer) by mechanically fastening with SBT tubes and SBIW-70x70 pressure plates. SarnaTherm G can be loose laid if sufficient ballast weight is provided immediately to resist wind uplift pressures.

A vapour control layer will be required when SarnaTherm G is used.

- Vapour control layer:

Loose laid over any smooth surface with all side and end laps overlapped a minimum 80 mm, then sealed with Sarnavap jointing tape. At parapets and upstands, Sarnavap must be carried up to the upper edge of the thermal insulation and sealed to the upstand/ penetration with Sarnavap jointing tape, to form an airtight seal. When installed vertically, Sarnavap must be mechanically fastened along its top edge.

If the surface is rough, a layer of Sarnafil Type T fleece should be used as cushioning layer.