Restoring a brick, 100 yr old sagging hearth

[chimneymac]

I've recently inherited a few gorgeous fireplaces (4) that are in need of some repair, all built in the late 1800's. They have not been burned in for some time (years) and the hearths seem to be sinking/sagging/leaning, all in the same way but to varying degrees of severity. These aren't corbelled like you normally see and hey appear to be arched or supported from wooden cross members.

The photos attached, you can see how they are beginning to give way and pushing the support structure. There is a definitive gap between the flooring and the brick - this is seen both above the floor (causing cracked tile) and seen from the cellar. I've also added an additional photo of the same method but in better shape.

Can any of you help identifying the construction techniques or the best course of action for these repairs? Any information on this design or construction techniques? I want these to be brought back to be structurally sound (at a minimum), or able to burn in (hopeful).

 

[gthomas785]

If you're worried about the arch collapsing, I'd try to fabricate some sort of steel support to keep that front beam from bowing out, that should hold it. Then re-set the top layer of bricks to make the hearth extension level again.

Did you measure to make sure all of that wood framing is an appropriate distance from the fireplace? I don't remember the rules off the top of my head but in many old houses they built framing right up against the chimney which is not safe at all. From the picture it looks like yours may be ok.

 

[chimneymac]

If you're worried about the arch collapsing, I'd try to fabricate some sort of steel support to keep that front beam from bowing out, that should hold it. Then re-set the top layer of bricks to make the hearth extension level again.

This is a great idea - the beam is already bowing out and the hearth has sunk about an inch. I'm wondering if it should be raised back into position, add permanent supports, then re-set the top. Or if it would be better to rebuild the hearth all together?

Did you measure to make sure all of that wood framing is an appropriate distance from the fireplace?

Yes and it's according to code. I used the technical notes from the brick industry assoc to confirm. Good question though, I also have seen a lot of old houses that are not. The exception, these are unlined but multi-wythe.

 

[gthomas785]

Well I'm not a mason. I'd be tempted to slowly jack it up into position, but you'd want to be sure you're not creating new stress within the masonry. Is there a big crack where the hearth extension meets the fireplace?

 

[gthomas785]

On the other hand, if it's not too bad you could just support it in place and keep it from getting worse. It's pretty normal for an old house to have a few dips here and there.. like mine