Center chimney sagging

Questions and answers relating to houses built in the 1800s and before.

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Joined: Thu Oct 15, 2020 12:55 pm

Center chimney sagging

Post by dsaturday »

Hello everyone!

I've lurked these forums as a guest for a while. I finally made an account as I would like some help with my structure from other old house folks. I grew up in a 100 year old house. My fiancé and I bought a 130 year old house a few months ago.

Foundation is in very good shape. And appears mostly level from wall to wall (checked with water level). The structure is quite simple. There are 2 carrying beams (8x8s or 9x9s) spanning the east/west run of the house. There are 3 separate sections of floor joists running north/south (2x8s, rough sawn, all mostly in good shape). One of the main beams is fantastic. It spans the entire east/west run. It is supported by two posts (6x6s) sitting on raised concrete footers. These are either original or near original as far as I can tell.

The other carrying beam is actually 2 separate beams, pocketed into the center chimney. My suspicion is that the chimney (due to its tremendous weight in the central location) has settled more than the foundation. As a result, the beams that are pocketed into it have sagged down too. So the ends of the beams notched into the rim joists are level with each other and have settled very little. But the ends of the beams pocketed into the load bearing member (the chimney) have dipped down approx. 2".

I'd like to address this issue with jacks. I want to use the screw kind that you can move VERY slowly. My plan is to give the jacks a 1/4 turn or 1/2 turn each week. Then give the house a week to rest. Then turn again. I understand that this may raise the beams about 1/8" to 3/16" each month. It would take me a year or more to get where I need to be.

I intend to pour raised footers (like the ones supporting the other carrying beam) to support my permanent supports when I take the jacks out and shore up the structure. Each piece of the carrying beam is approx. 10 ft long or so.

I'd like any tips, advice, etc. that you have. I know some of you have done this with your houses. I intend to be very conservative and go very slow. And I intend to overbuild my posts and footers that will permanently shore this thing up. I understand there is a risk of cracking walls and ceilings. And that I need to carefully look over the plumbing and electrical to make sure nothing will get messed up. For those of you who did this, did you experience any damage? If so, how quickly did you jack? Again, I'm just in the initial planning stages here. I'd like any advice you all might have.

I'm holding off on major renovations to the rest of the house until I get this issue settled.

I've tried posting a picture here. If it doesn't work, there is a link here:


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