How many cans of spray foam do you need?

Measure the perimeter gap: e.g. 12 m length × 2 cm width × 5 cm depth ≈ 12 L expanded foam before waste — often one can at 45 L yield. Uneven gaps or overfilling for trimming can need two.

Handheld cans are for small gaps and sealing — not for full cavity fill (that needs professional PU kits and fire-rated assemblies). This tool sizes DIY gap volumes only.

Common reasons: overstated yield on the tin, foam escaped before curing, or depth was deeper than measured. Cold cans expand less — store at room temperature before use.

PU foam is water-resistant when cured but UV-degrades if left exposed — paint or seal per manufacturer. It is not a structural filler; deep loads need backer rod plus sealant, not foam alone.