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bdisking 04-03-2014 05:22 PM

Sagging garage
I have an old garage from around 1900 and it is sinking mainly on one side. But it has no concrete foundation it is just wood flat on the is a big garage 30feet by 20 feet and 2 story's tall. First thing is how do I get it level then how do I keep it supported. Any help would be great thanks.

nealtw 04-03-2014 05:41 PM

Welcome to the site. We will need to know how it is constucted and there will be lots of question before you get answers to this. Can you post some picture.
It is important to figure out if it is built like a house or like a barn, how the upper floor is attached and supported and how bad it has sagged.

Wuzzat? 04-03-2014 07:13 PM


Originally Posted by bdisking (Post 102946)
then how do I keep it supported

You'll need to estimate or calculate the weight of this building. 20 x 30 x 120 lbs/SF(?) = 72,000 lbs = 36 tons, so each corner weighs 9 tons.
$75 and up for a bottle jack.

How far do you need to lift it? If it's 1 ft and you can somehow put 1 hp into this jack handle then it'll take you 30 seconds.
Take at least an hour and check frequently if the building walls are being twisted out of shape. Taking several days is probably safer.

carnuck 04-11-2014 03:47 PM

How are the timbers inside? Is it dirt floor?

bdisking 04-12-2014 11:08 AM

3 Attachment(s)
The sill plates are like a 4x4, studs are 2x4 I haven't tore up any floor boards to see how its built but I can if needed

Wuzzat? 04-12-2014 01:40 PM

If the sill plates are bent from decay or structural failure then you have real problems and even if they're not a 9 ton concentrated load or a 9 ton distributed load will bend a 4x4 that is not uniformly supported by the ground.

This thing should be raised by at least three jacks with one at the corner. But, if you sight along the sill plates and they're high in the middle it's the corners where the soil has subsided.

Since there's no drywall you can see everything and make a pretty good estimate of the weight of this structure.
A default value for the density of softwood is 35 lbs/cu ft. How many pieces of what length and width and depth are there?

As to cause, maybe you can find it here

nealtw 04-13-2014 01:34 PM

I would be surprized if this thing stude here for that many years with out a foundation, I would like to see you dig around a little and see what's under there.
You will likey have some bad floor joists under the floor too, if it's built close to the ground.
The fix for one side goes something like this.
Remove enough floor sheeting to dig down and install a concrete footing about 18" square and eight inches deep on solid undisturbed soil, how ever deep that is.
Do this at each end of the wall and in the middle of the wall.
If the corners of the building are level with each other, build cribbing on the corner footing to about 2ft above the floor.
You build 2 beams out of something like 4 2x12 long enough to reach from the corner to the center where the jack will be.
In the center you place the jack with about a 2ft peice of 6x6 steel H beam with a cradle welded to it to fit the top of the jack to keep it centered while jacking.
On top of that fits the two beams. You set the jack height so the beam is reasonable the same height from the floor above and build a temp wall from the beam to the floor above.
With angle braces on the wall from high to low so it won't rack and braces from the new wall to old wall and from new wall on an angle to the floor above.
In other words you brace the crap out of it so everything stays together when it is being lifted.
If you find rotton floor joist or you are afraid they won't go up with the rest of the building you tie the two floors together with more braces.
The one thing about hydrolic jacks is, if it's not big enough it won't lift it.
You also set up two spots where you can shim as you go so if you have to reposition or you have a failure, you have captured all gains.

Wuzzat? 04-13-2014 02:31 PM

^do what he wrote. . .:D

Today I have learned a new word.

bdisking 04-14-2014 06:10 PM

1 Attachment(s)
This is how it looks underneath all the wood looks surprisingly good except what you see at the top of the picture were the sill is rotted out only on the side that is sagging.

nealtw 04-14-2014 06:52 PM

Is the photo from the back or from under the window?

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