cracking concrete in 1945 fireplace
cracking concrete in 1945 fireplace
(OP)
See attached image. It shows a fireplace of river rock in a 1945 house with a concrete hearth of serious (6"?) thickness that has separated away from the cracked-up fireplace floor. I will be resupporting the hearth framing from underneath but am unsure what to do with the fireplace floor and the very large crack between the two. The chimney has been inspected and is in working order. The owners would like to have wood fires in it again. As best I could tell, the fireplace floor is approximately 2" thick with river rock stone below it. (That's a cleanout into the river rock wall below in the rear left corner of the fireplace floor.)
Any thoughts?
Any thoughts?
Please remember: we're not all guys!





RE: cracking concrete in 1945 fireplace
So you have to either close up the gap with something modestly flexible and 110% fireproof, or tie the two together with a fireproof link. Check the fireplace stores near you - they may have a repair mortar. Matching color will be hard. Caulk? Probably not flame-resistant enough.
Have you verified the slab is not going to move more? The slab is to catch sparks popping out of the fireplace onto the rug or wood floor. A thick but decoative metal tray could span the difference in height and do the same thing. Say, 1/4 inch thick, with two adjustable legs on the far end to hold up edges of the tray over the uneven surface. . Then add a decorative lip (2-3 inches high perhaps) to the tray to prevent spills of the trapped sparks..
RE: cracking concrete in 1945 fireplace
I'm considering removing all the cracked up flooring in the fireplace and then repouring, but yes, that crack moving more would be the main concern. I like that pan/lining idea a lot. Thanks!
Please remember: we're not all guys!
RE: cracking concrete in 1945 fireplace
The left side of the firebox floor looks like it has heaved. The right side of the hearth is relatively flush, but has moved away from the chimney (apparently) more than the left side. How long did it take for this to happen?
Is the chimney on or near a slope?
Is the hearth on or near an opposite slope?
Is there any separation between the hearth and the wood structure?
Is there any settlement noted in other portions of the structure?
Is the structure supported on piers?
As for the floor of the firebox, it looks like it has been patched a few times, apparently with conventional portland cement concrete. I would concur that this needs to be removed and re-placed, but this time with refractory cement concrete.
RE: cracking concrete in 1945 fireplace
Looks like heaved, but I'm not sure it actually did, or at least not much. It's a play on the eyes from the crack being so crazy wide. Here's another pic:
Nope. There is a basement below the floor system but the chimney itself is part of the foundation. It seems rock solid (pun not intentional but quite appropriate).
Hearth is framed around by double wood joists with wood below, and concrete poured above. The garage door was supported on this. The framing in this area has sloped down and away towards the middle of the house, creating the crack. see:
Not the best pic, but look hard and you'll see the left double joist (with a ledger stuck on it so it looks like 3), the flat horiz boards under the hearth concrete, tracking for the garage door, the header between the double joists at the end of the conc hearth, the shortened joists, and the yellow hooks for the ladder. You can also just see the top of the cleanout in the river stone wall at the bottom left-middle of the pic.
None at all, that I can see.
There's a lot on the porch, which is the other side of this wall, but the porch is clearly falling away from the rest of the house and the chimney, which are strong.
Nope. Whole house is river stone foundation.
Please remember: we're not all guys!
RE: cracking concrete in 1945 fireplace
RE: cracking concrete in 1945 fireplace
Please remember: we're not all guys!
RE: cracking concrete in 1945 fireplace
RE: cracking concrete in 1945 fireplace
RE: cracking concrete in 1945 fireplace
RE: cracking concrete in 1945 fireplace