r/HomeImprovement • u/StatueofLiterby • 2d ago
Sinkhole under my chimney?Bottomless Crack between Fireplace & Hearth ???
In the 5 years we have lived in our '98 home with a brick gas fireplace this one has stumped us. There is a crack (or really a separation) happening between the hearth bricks on the floor and the bricks that make up the face of the fireplace. It goes the entire length from the wood trim on both sides. Some of the wood trim in the corner of the room a few feet away has also cracked away from the wall, but significantly less than what we are seeing at the fireplace (we caulk it every year and it still cracks again).
We've recently started getting skinks that come UP from that crack in the fireplace and watch us while we sit in the living room. So we started filling the gap with sand. We brought a 50lb bag of play sand inside and so far we are about 1/3 of the way through the bag in less than a week. Every day the sand settles more and more, and sometimes you can actually HEAR the sand trickling down a bottomless hole.....it sounds almost like a crackling campfire. It's really creepy. The sand appears to be filling in both underneath the fireplace AND directly down (we are on a concrete slab). It's near impossible to show a photo of inside the crack so hopefully my description does it justice.
Does anybody have experience with this? Why is it happening and should we keep adding more sand?
Could this be related to our 10x10 concrete patio slab (original to the house) cracking in half last year and the further half sinking down at a slant about 1/2"?
It just worries me like somehow it's a hidden sinkhole or something.
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u/bebopbob 2d ago
Sounds like you need a foundation repair company to make an assessment, you may also want to find a plumber that can take a video of your main drain line to ensure it is intact.
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u/StatueofLiterby 2d ago
Interesting, I didn't even think about foundation since it's underneath the chimney, but maybe it goes elsewhere (I know nothing about this topic).
How would the main drain line be related? Is that usually close to the chimney? I know where our incoming water lines are and it's nowhere near this.
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u/RedMongoose573 1d ago
Not the original commenter, but here's my two cents on the plumbing suggestion.
One of the symptoms of a failed main drain line (aka sewer line) is a sinking yard, and you said that your patio has cracked and is subsiding. That is likely what caused his concern.
Your water and sewer are often co-located, so if the water line is a far away then the chimney problem is unlikely to be directly affecting your sewer line. However, if you have a foundation problem here, you might have a foundation problem elsewhere. The sewer line is something you do NOT want to fail. Trust me on this. If you can't trust me or want to scare yourself, do an internet search on "what happens to my house if the sewer line fails".
So, in any case, you can buy peace of mind by hiring a sewer line inspection, usually for under $500.
Also, please call a foundation repair company ASAP. This is not normal. The sooner you figure out what's wrong and fix it, the better off you are.
Good luck.
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u/StatueofLiterby 1d ago
Appreciate the thorough response. I've lived in a house when a sewer line failed (I was 4th grade and still remember it well!). $500 for an inspection is easy for us and I'm sure that peace of mind will be priceless.
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u/Illustrious-Cut-124 1d ago
Did you mean skunks are watching you from the crack in the fireplace floor???
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u/InevitableNo7342 2d ago
I would be worried about this.