Question 1

Where is roll waterproofing used?

Accepted Answer

On flat roofs (as the main or secondary layer), on foundations (vertical and horizontal damp-proofing of footings and slabs), in basements, under tile in wet rooms, and in pools (with special compounds).

Question 2

Torch-on or self-adhesive?

Accepted Answer

Torch-on (applied with a gas burner) is tougher and longer-lasting but needs a professional. Self-adhesive is easier, cold-applied with no open flame, and suits garages and basements where space is tight.

Question 3

How many layers do I need?

Accepted Answer

A flat roof takes 2 layers (a perforated, partly bonded base layer plus a fully bonded top layer). A foundation takes 2 layers with seams offset by at least 150 mm. A single layer is for temporary or undemanding cases only.

Question 4

Why a 15% overlap?

Accepted Answer

Building codes call for 150 mm overlaps on end joints and 100 mm on side joints. These overlaps raise total material use by about 10–15% over the bare surface area.

Question 5

Do I need a primer?

Accepted Answer

Yes, for torch-on membrane on cement substrates. Primer seals the pores and ensures adhesion, at about 0.2–0.3 L/m². Let it dry fully (1–2 hours) before laying the membrane.

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