Gaps around ceiling boxes must be sealed with an intumescent fireblocking caulk or foam. Ordinary spray foam burns too quickly, opening the gap and creating a chimney effect that feeds the fire.

The booth is built from a single 40″ x 60″ sheet of 1/2″ foam core board, a furnace filter, and a vent fan modified to fit his shop’s system. The whole thing cost less than $200, most of ...

Spray foam is the best way to seal and insulate a cathedral ceiling with no ventilation. It eliminates the condensation hazard that’s so common with ceiling designs like this.© Photo Robert Maxwell ...

The lender says it expects enquiries about spray foam to "skyrocket" as more people seek to better insulate their homes. It is advising people to make sure they only use reputable firms.

People are putting their homes at risk by using rogue companies that offer spray foam insulation, according to one of the UK's largest mortgage providers.