How soon before...

[Milehighxr]

I have to do something about my sinking garage floor? I do plan on consulting a local contractor, but I have noticed that one side of my garage floor is sinking, and the pad now has 2 cracks in it. One runs along the 30ft length, and the other perpendicular to it. The long one concerns me most, as it has created a 3/8" -1/2" gap at the overhead door. I have already shimmed the overhead door seal once, because there was a gap in that area, but now it is bigger. Basically this garage had been built(by a PO) on one large 30'x20' pad. There had not been gutters anywhere on the house or garage(I put some up this summer).

I don't have funds to rebuild the garage now, so I'm hoping there is a cheap fast fix, like pumping concrete under pressure underneath the low area to bring it up, or at least stop further sinkage(if that's even possible, I've seen concrete pumped to stiffen, a not so dense floor under heavy machinery).

 

[RCStocker]

I am a general contractor and architect.

There are many factors that you did not state?
Where are you located.
What is the frost depth
Are the footings for your garage down far enough below the frost level.
Did the sight have a soil compression test before it was built.

There is a lit of other things including the garage floor should have had welded mash laid in to give it extra support. I know most garage don't have mesh but it adds a lot of strength. They use steel in cement because the expand and contract at the same rate.

Cement must be poured as dry as it can be for the conditions and then kept wet as long as you can keep it wet after it sets up. This will keep and make it very hard.

Yes you can have a foam pumped in under it to level it up but that will not fix the cause of the floor sinking. If you are in a wooded area the ground could have a lot of build up of leaves and be very soft. I have seen buildings built over old saw mills and the sawdust let the buildings sink over a foot.

It sound like there was no soil test done to see if the site needed re-compacting.

I would hire an engineer to come and do a soil sample test. I have seen them raise slaps on elevated porches that were sagging. It can be done but if the ground is soft I would say you are wasting your money.

If the structure is sound then I would break out the floor and dig out the dirt several feet down and back fill with wet sand. It will not compress and then put in new rebar and wire mesh before the new floor is poured.

A normal pour is 80 square feet per yard. That is for a 4 inch pour. I would pour the floor a minimum of 6 inches and where the cement is at the door opening I would pour a good footing under it so it will never sag.

Hope this helps.

 

[Fizbin]

My garage floor is also cracking and I'm begining to find out that there is NEVER a CHEAP fix for a foundation problem.

 

[CNGsaves]

Let's SEE pics of damage that is happening to garage floor.

There was recent GJ thread on leveling garage floor with couple solutions of . .
. . . . Mud Jacking or Poly Level.

 

[Ross/Kzoo]

The option to pour grout under the existing pad is NOT cheap. It may be about the same as removing and pouring new.

 

[Andamo]

My 24' x 36' garage floor dropped in the one back corner about 1.5'' The entire area that dropped is about 20' x 20'. I had a company come and give me an estimate drilling holes and pumping in grout to level it all up and the price was in the $7000 range.

 

[Throbbin Rods]

My dirt guy never hooked the garage foundation drain to the one on the house. All the water sat there and basically would freeze and heave the floor. Big mess, floor is not able to be salvaged. Thankful that I put in 4 foot frost walls under the floor. At least I can rip it out and re do. Some of the smaller cracks are pictured below. Right side of the garage slab sunk down at least a foot after cracking off the rest, but that area has a bunch of stuff stacked there for now.

 

[Milehighxr]

RC stocker, I doubt there was ever a soil test done on this site. I do know that this site was farm land once upon a time, and I know my house(a modular, er I mean manufactured) has been here since 1983. It sits on very large concrete blocks(for lack of a better term) that are sunk into the ground. I think(dunno for sure) that frost depth around here is around 18-40inches. I know that the area around the blocks the house sits on always stays bone dry. IMO(I grew up in southern MI) there are absolutely no trees around here, though I am staring at several tall ones in the park across the street now...

I don't know what if any footing there are under the garage floor/slab. Breaking out the floor is NOT an option, as the garage structure is built directly on the floor, there is no rat wall, and my ceiling in the garage is just short of 8' because of the way it is all built.

Kzoo/Ross, and Adamo, $7000 is far cheaper than the nearly $30-50K it would cost me to rebuild the whole structure the right way. If I can buy a few years, or more with $7000 it would be worth it to me, unless of course I have 10yrs before I need to do anything...

I'll get pics for you guys later of what I am talking about. Hopefully I'm getting worked up over something that doesn't need to be attended to for at least 10yrs...