Preparation of substrate:
Do not start applying membrane until all surfaces are clean, smooth, dry and free of anything that would prevent the membrane from adhering properly.
Make sure that drains are secure and properly installed.
The roof should slope evenly and continuously towards the drains with a minimum fall of 1%.
Ensure that the fall around the drain is not excessive to avoid creasing of the membrane.
Prime, metal, concrete, brickwork and fibre cement with a compatible solvent based Wrimco SBS primer at 6-8m2 per litre (not required for factory painted metals or mild steel).
All surfaces to be primed must be free of rust, dust or any residue such as laitance which may cause lack of bond. Surface grinding, acid washing (and subsequent neutralising) or high pressure water may need to be employed.
The membrane is best applied on the same day as the primer.
Concrete and brick
Plywood and timber
Aluminium, copper, mild steel and well-weathered zincalume / galvanised iron
Unroll the membrane, making sure that the side lap joint is aligned with the low point of the roof. Reroll one end to the centre of the roll and apply; then proceed with the opposite half. Proceed up the slope with further rolls.
In the case of Wrimco SBS Granules, degranulate at laps by pressing the granules into the SBS material using either a hot trowel or a degranulator.
The tip of the propane torch should be between 150mm and 300mm from the surfaces, depending on weather conditions. The blue end of the flame gives the most heat.
The torch and thus the flame should be moved continuously in a regular manner from side to side, pausing momentarily at either side to ensure a 2-3mm flow out. The polyfilm should be completely burnt off.
Make sure there is always a small bead of molten bitumen in front of the roll. If in doubt, reroll and you should see strings of bitumen between the substrate and the roll.