APP Membrane
Atactic-polypropylene-modified bitumen sheet, torch-applied to a primed substrate with lapped and sealed joints. Usually 3 or 4 mm thick, plain or mineral-finished.
On an actual building
The APP modifier raises the softening point, which suits exposed Indian roof temperatures better than unmodified bitumen or SBS. The visible bead of molten bitumen at each seam is the confirmation the lap has fused.
What we most often have to correct
That thickness alone determines quality. An under-torched 4 mm sheet performs worse than a properly fused 3 mm one.
Terms that come up alongside this one
- SBS Membrane
Styrene-butadiene-styrene-modified bitumen sheet.
- Bitumen
A viscous petroleum-derived binder, the base material of most sheet waterproofing membranes and of traditional built-up roofing..
- Primer
A preparatory coat applied to a substrate to seal it, improve adhesion and provide a compatible surface for the system that follows..
APP Membrane — questions we get asked
What does app membrane mean in waterproofing?
Atactic-polypropylene-modified bitumen sheet, torch-applied to a primed substrate with lapped and sealed joints. Usually 3 or 4 mm thick, plain or mineral-finished.
Why does app membrane matter on a real project?
The APP modifier raises the softening point, which suits exposed Indian roof temperatures better than unmodified bitumen or SBS. The visible bead of molten bitumen at each seam is the confirmation the lap has fused.
What do people commonly get wrong about app membrane?
That thickness alone determines quality. An under-torched 4 mm sheet performs worse than a properly fused 3 mm one.
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