The Waterproofing Membrane
The membrane shall be Cosmofin FG LL or FG LLV, 1.5 mm thick, polyester reinforced PVC together with Cosmofin F, an unreinforced version of Cosmofin FG, which shall be used for detailing purposes.
The main lap selvedges are to be free of exposed reinforcement when welding is complete and checked off. All junctions are to be homogeneously welded – adhesives or tapes are not to be used for jointing nor detailing to pipes, penetrations etc.
Substrate Preparation (by others)
Concrete is to be finished to smooth helicopter standard, without ridges, boniness or sharp changes of plane.
Formed concrete to be minimum Class 3 with “sharps” knocked off.
Timber, fibre cement or plywood substrates are to be countersunk screwed, not nailed to avoid nail “backout”.
Ensure that there are positive falls in the substrate to outlets/ water egress points Brickwork should be struck flush.
Rock faces should be hand finished and flushed with mortar to remove “sharps”.
Adhesion to Substrate
The membrane can be strip-bonded to the substrate with Teroson EF TK 400 adhesive recommended by the manufacturer. For full bonding, please contact Projex Group for recommended adhesives.
Base Angles
The perimeters of all deck areas at upturn bases are to be mounted with Cosmofin membrane coated steel angles, fitted in accordance with the manufacturer’s instructions.
Upturn Terminations
The upturns to all vertical faces are to be carried to the height(s) specified (nominally a minimum of 150 mm). The tops of all upturns are to be sealed off with the standard Cosmofin membrane coated steel profile, fitted to the structure before welding the membrane thereto, primed and sealed with one part urethane.
Rainwater Outlets, Pipes and Protrusions
Detail to all drains, pipes, conduits and similar connections all in accordance with the manufacturer’s instructions.
