I have a stone fireplace and just installed a new door. But there's gaps because the stone is irregular. I tried using fireplace cement from the inside but it's hard to get in there and keeps falling out.

Is there any better material I can use? Some kind of sealant that won't burn up?


  • if the gaps are not two big rockwool may work
    – Ed Beal
    Dec 4, 2015 at 20:04
  • I'd look at mortaring (or simply bolting) in a frame against which the door would seal better.
    – isherwood
    Dec 4, 2015 at 21:50
  • Can you remove the door and then smooth out the edges before reinstalling?
    – JPhi1618
    Dec 4, 2015 at 22:12

1 Answer 1


the best way to this is with fiberglass gasketing, sometimes called door rope. its just a fiberglass rope. you get some hi-temperature sealant for same, inject into the area it is to fill so that it covers stone and the metal assembly. then, rub it all over the rope (cut to the right length ahead of time) and then simply squeeze into the gap. different diameters might need to be used, but usually one will do. tape off all adjacent areas and where gloves as the sealant is quite gooey and makes a big mess. wipe the area off with acetone after to clean up prior to removing the tape



they will sell something similar at your local big box building store

  • I ended up just sealing with hi temp caulking. Wasn't able to find any door rope and I didn't really need it. Used about 4 tubes though. Jan 9, 2016 at 18:11
  • i hope it works out for you. the reason you use the rope is it provides mechanical reinforcement for the sealant. without it you will probably see cracking and spalling shortly as the sealant hardens and crystalizes. if it fails on you, repeat the process but with the roping. then you should have a fairly permanent repair. good luck though. Jan 10, 2016 at 2:05
  • Important to note that fiberglass is a potential carcinogen especially posing a high risk to those who are exposed consistently over a long period of time. see here for more info survivingmesothelioma.com/… I wood use steel wool in this case since it provides the same structural support then I'd add caulking over it.
    – Joe B
    Sep 27, 2019 at 3:02

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