Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

What product to use around radiator supply pipe in floor cavity?

HenrikWHenrikW Member Posts: 6

I have somewhat large holes around my steam radiator supply pipes coming out of the floor, which are black iron and possibly galvanized. What material can I put around between the hardwood and the pipes to close the holes? I've had to widen the holes due to rubbing noise between pipe and sub floor during heating cycles and will cover with floor flanges but wanted to close the gaps with something flexible to insulate against noise, draft and bugs etc.

I've seen a lot of forums mention steel wool, but what kind, assuming not scrubbing pads.Also what about fire stop from the caulk aisle? Maybe a combo of the two? I just want to do it right once.

Then you in advance for chiming in


  • STEVEusaPASTEVEusaPA Member Posts: 4,454
    Oh I don't know about fire stop. Usually smelly and carcinogenic.
    Can you squish in some foam pipe insulation?
  • Jamie HallJamie Hall Member Posts: 13,495
    Steel wool would work fine. Hardware store.
    Br. Jamie, osb

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • FredFred Member Posts: 8,443
    Depending on how large the hole is, buy a section of 1/2" and/or 1" steam pipe (fiberglass) insulation and cut it into two or three inch widths to push in around the pipe. It is preformed based on pipe diameter and you should be able to trim it to floor level so that your floor flanges fit nicely over it.
  • EBEBRATT-EdEBEBRATT-Ed Member Posts: 7,340
    Mineral wool insulation slightly green in color. HD or Lowes would have it
  • Intplm.Intplm. Member Posts: 1,200
    Commercial scowering type steel wool if you can get it at a kitchen supply store has worked best. It is larger and fills and molds the best around steam pipes. If not , go with the steel wool on the shelf at your nearest hardware store, combined with fiberglass pipe insulation.
    Then top the hole with a hinged escutcheon.
    If the holes are too big for just one escutcheon, start with an over sized one and work your way up from larger to smaller. Building a circular type pyramid.
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!