Gap between wall and fireplace

[William Galbraith]

I found this gap between the wall and fireplace inside the firebox. The bottom gap is about 1/4 inch, the side gap is slightly wider and the gap at the top of the firebox is over 1". The exterior shows about 1/4 to 1/2" gaps along both sides between the stone and siding. The home is over 30 years old so settling has occured. Good old red clay of Oklahoma. That is why we have ACME brick located here.

The exterior fix should be easy with mortar. Is there special mortar that must be used to repair the inside because of high temperature? I imagine it should be a relatively dry mix.

[Cary Seidner]

Yes. You need to use refractory mortar in a fireplace.

[Darren Miller]

Fixing the gaps will be a temporary fix; the crack will only open again due to settlement. The settlement problem needs to be addressed.

I had one a little worse than this about 8 years ago; cost $30,000 to tear down and re-build. It was a fireplace but also had a flue for the boiler & water heater.

[Nick Ostrowski]

Fixing the gaps will be a temporary fix; the crack will only open again due to settlement. The settlement problem needs to be addressed.


I thought the same thing Darren. In pictures #2 and #5, you can see the displacement in the cracks. In #5, it appears the area was repaired/patched once and has cracked again. Cracked patches are one of the easiest ways to guesstimate whether or not the issue is ongoing.