# reinforcing fireplace foundation



## zeffer111 (Sep 15, 2011)

We have a fireplace with an ash pit.




























But as you can see, its pretty rough looking underneath. I would like to seal up the ash pit door and reinforce the entire thing before I completely cover up the exposed foundation with closed cell insulation foam underneath.

What do you thing of this approach?... Build a frame to seal off the area between the two "pillars" that are on either side of where the ash door is (as you can see the two pillars are starting to crumble a bit) and pour concrete down the ash door so that a solid block is formed, reinforcing the whole structure. I don't use the fireplace all too much, so I don't mind losing the ash pit "feature".

What do you all think? If you need more pics or detail let me know.
I'm pretty desperate for some good ideas and advise because I'd like to do as much as I can myself as funds are pretty tight.

Thanks.


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## kchunt (Aug 15, 2011)

*reinforced fireplace footing*

i can't see what the block piers are for.i hope there kinda suporting part of the foundation of fireplace.your idea is ok to pour concrete thru ash dump.dig down to good solid ground .you can use 10" steel culvert pipe cut to length verse wood forms.you can't put concrete up to floor joice.i would use 3x6 inch 'I' beams long enough to span under the floor joice.you can hold them in place with other 2x4s put culvert pipe under them.pour your concrete right up under them. If you have good acess you still can use wood forms,I'ts just hard to nail in place to hold while you pour.It looks like they cut the floor joise to pour the slab.bad idea. good luck.ken.

we all no alot but can only do a little----:yes:an:no:.


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## zeffer111 (Sep 15, 2011)

The idea is to create a "flat" surface so that I can spray insulation foam on the exposed foundation walls, I also want to reinforce the fireplace, as you can see it's crumbling a bit.

What is the specific reason why you say I shouldn't fill up the space between the fireplace foundation pillars right up to the bottom the fireplace?

Anyone else with ideas, I'd love to hear them.


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## pyper (Jul 1, 2009)

Here's something you need to be cautious of: Fire hazard.

Whoever built your fireplace presumably knew something about the R values of the materials used and the clearances to combustibles. As I look at your photos, I see noncombustible material. Do not, under any circumstances, put combustible material in contact with the fireplace assembly without in some way verifying that it is not creating a fire hazard.

Just as a point of reference, many wood stoves require an r-value of 2.0 between them and the nearest combustible. That's something like 12 inches of brick. And a wood stove has a 4 to 6 inch air space, while your fire is built on your hearth.


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## Ron6519 (Mar 28, 2007)

You have a 2 or 2 1/2 story masonry mass supported by a less then adequate structural support.
I would seek local guidance on how to rectify that issue before any other.


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