If the sprayed polyurethane foam (SPF) was not apllied correctly, the roofing ply starts to dust, delaminate and it will loose itīs hydro-insulation capabilities.
Minimum roof pitch for the spray foam roofing
The minimum roof pitch suggested for SPF roofing is 3 degrees (on all parts of the roof, no 1 degree valleys).
Spray urethane application rules
- the roof surface has to be dry, clean, degreased;
- the air temperature must be minimum 10 Celsius degrees;
- the roof temperature must be minimum 12 (but better 15) Celsius degrees;
- the air humidity under 75%;
-no or almost no wind;
- every single layer of the PU must be maximum 15 m...
Polyurethane boards vs. sprayed urethane foam
Polyurethane, as a roofing material, can be applied in two different ways:
- as the PU boards (urethane is foamed into the molds where the foam solidifies into the required shape);
- as a SPF or spray polyurethane foam (where the foam - a liquid substance under pressure - is sprayed directly on the roof surface).
Polyurethane boards
Apart from the simple PU boards that need to be laid onto the roof where already the vapour barrier material was applied, there are numerous types of much more universal urethane foam boards, e.g.:
- bords where the bottom part of the board was covered with the thin ALU foil or asp...
