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garage foundation question

3632 Views 35 Replies 13 Participants Last post by  Fouthgeneration
I'm looking for some advice and hoping I'm asking in the right section here. My garage is about 17'x17' and in rough shape. I can push it enough to see it move very clearly. Was hoping to support one wall at a time and rebuild one side at a time.
The slab on the inside is poured inside the walls, and the studs appear to go into the dirt so they are all beginning to rot. I did some digging and it appears so be a stone footing under the walls, can't post a Picture at the moment but the stone is of a yellow color, not sure what it is. Is it possible to expose the stone and lay a course of block on top of it?
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I wouldn't. If it's worth doing, it's worth doing right.
Can you use a masonry saw and make a cut line, use 2 - 2x6s nailed together as a beam and 3 bottle jacks, one at each end and center and use them to hold one wall up at a time to reframe? my garage at one of my rentals is 22x22 and that's how I did it. although I didn't have to cut the slab since its just a dirt floor. I ended up having to use shovels and dig the old footer out and pour a new one, one wall at a time using bags since it wasn't enough to get a truck for each side. I think I have some pictures I could post but ill have to check. all that work just to save the brand new roof and roofing trusses the previous owner had used on it.

depending on where you are, I'd be hesitant to just lay block on a stone footer, it would be subject to heaving if you have freeze-thaw cycles where you are.
I'm in Minnesota so definitely freeze thaw. As far as the jacking up and all I can manage that fine. The only thing I'm stumped on is getting something solid to rebuild off of. I'm pretty positive the stone goes down to the frost line, but the top of the stone is below grade level. I wanna bring it up without replacing.
well I wouldn't even attempt to use the stone footer without being 110% sure and the only way to know for sure it excavate as deep as the stone goes. personally, even if it was down to the frost line, id prefer to have actual concrete. its going to take more water to puddle and freeze under a large mass of concrete then it will to push up a pile of stone.
As far as building it right, I agree completely. Thing is the garage is to small to even fit any of my trucks, and I wanna be moved out of here in the next two years. So I don't wanna throw too much money at what's pretty much a large shed.
Cut off the rot one side at a time and pour concrete extension to get you out of grade 8".

Drill down into the stone and add some rebar to pin the extension then place 2 or 3 #4 bars continuous.

Might want to dig down to confirm the stone footing is at frost line and don't forget to set anchor bolts for the new sill plate.
That was another idea I was toying with, building some forms and poor on top, so I could get some concrete on both sides of the stone, kinda straddling it.
Sometimes you're better off repairing it to the way it was. The only thing you can bet on if you pour cement over the stones is the stones will start moving.
Not trying to be an AH, but are you a contractor? Appears like you are not:eek:
I've spent the last 4 years in construction. But I have very little experience in buildings that are 100+ years old like my house. So I've got a little bit of a learning curve here.
Not trying to be an AH, but are you a contractor? Appears like you are not:eek:
Gotcha, just curious because the only posts you have are reference to your own house...don't you know that working on you're own house makes you no money :laughing:
These are sometimes and archeology project to understand what was done to get it to the state it is now. Also, you should put your location in your profile - it can make a difference in what advice you're likely to get.

It isn't uncommon for a small farm building to have been built on a single layer stone foundation, even where the ground freezes a few feet down, or it may have been several courses of stone. They can be post and beam, pole, balloon, or conventional framed. The concrete floor may be original, or it may have been added later. You get the idea.

First, get a shovel and dig next to the rock foundation to see if it was back filled to raise the level up high as it is, and see roughly how far down the stone foundation goes. A later grade change is more common than building these so the sills are below grade. It's possible that it has settled several inches over the years, resulting in the sill being below grade, but thee wouldn't have been much slab settling. Also, uncover the sill on the outside so you can see how bad it is - it could be dust by now. You also should check to see if there has been significant settling relative to the concrete slab - not always possible to tell conclusively.

In a case like this, you may wind up using a ground contact rated PT beam with a mud sill on top to replace what was there, and do a lot of stud trimming. masonry and concrete doesn't handle movement of old stone foundations well.
I've spent the last 4 years in construction. But I have very little experience in buildings that are 100+ years old like my house. So I've got a little bit of a learning curve here.
From what i saw digging yesterday, there is no actuall sill, the studs are sitting directly on the stone. The sill may have just rotted, but if the sill actually rotted away, I would expect to see much more rot on the stud bottoms. I'll dig more and get a better idea.
Sounds like you need a contractor. ...
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I like the slab ext idea with a stem wall if the footer is deep enough. Maybe have to excavate some stone to make a thicker pad. Maybe sand too.
There is a good chance this had a dirt floor originally, and the slab was poured on top of it - no footer on the slab. This was done on original construction as well, but usually the slab surface would be lower - more like sill level or even lower.
if the footer is deep enough.
The slab is in no way attached to the footing, all the garages around here still have dirt floors. So it was added later. It isn't real thick and there doesn't seem to have been good prep work prior, so the slab is also in really rough shape..
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Well I jumped the gun, the footing is only about 8 inches deep.. looks like it's gonna stay the way it is.
I expected that and considered it with my reply that's why I said to lower what's there first.

Not sure about your code but under mine, 600 SF & an eave hieght less than 10 ft you can skip the frost footings. It won't prevent season shifting & twisting but it may be an option for you.
The slab is in no way attached to the footing, all the garages around here still have dirt floors. So it was added later. It isn't real thick and there doesn't seem to have been good prep work prior, so the slab is also in really rough shape..
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