In article , ""Bob Smith
\(UK\)" " "Bob Smith \(UK\)" says...
I am aware of the expanging foam in a can for filling gaps.

Is there any equivalent product for covering flat areas?

I only want 2-3sq feet, so is it a case of using the gap filler version and
spreading it?

Could you box the surface that you want to coat, and line the box with
something that can stay in place, then just use the injectable foam to
fill it?