Fill a hole around a radiator pipe

Question

Any ideas how I could fill a hole around a radiator pipe - picture attached

Should I use an expanding foam product or some sort of patch?

Thanks, J

Answer 1

That's a large hole I would probably purchase a split flange cover (eschutcheon)

that goes around the pipe but unless you can find a large one a patch job will be in order first. The split flanges you want will be metal as the heat may cause problems for a plastic one. On the few hot water /steam systems I have worked on they usually have a small gap and fill the gap with insulation then a cover if you seal it tight you would be amazed how much noise it can make.

Answer 2

Patch the hole first as much as you can with pieces of drywall and then you can consider the split flange cover Ed Beal talked about. Personally, I would drywall it, then spray foam for air sealing if outer wall and then the flange.