Sunken garage floor

[JLeach]

Hey guys,
This is my first post. Im really enjoying this forum. Im getting alot of good info. I have a 30 YO attached garage that is 20X21 feet. I just moved in and i want to refurbish it. Im going to start by laying down some epoxy. I've decided on the Rustolum professional. I would like a little advice on how to tackle the 4 inch sunken corner of the floor. As you can see in the pics it sunk evenly. It did not crack or create any other problems. The older gentleman that had the house before me had the down spout hose running along side the garage and not away from the house. It washed out the dirt under the floor. Of course i fixed the drainage problem now im left with a sunken floor. Im thinking about just living with it as it is. Does anyone foresee any problems?
Thanks
Jeff

 

[mdbeck1]

Before you go putting epoxy on it check the floor pitch. If memory serves me right it should only have 1/4" every 3 feet (or something like that) and should slope toward the door. If it slopes the wrong way I'd seriously consider removing and replacing the floor or at least figure out some way to get the slope right.

It's pretty easy to check. Get a 6 foot level and a small piece of 1/2" plywood. If that isn't enough get two or three pieces of plywood to help determine the pitch.

 

[Stinger]

If it will hold water I'd look into mudjacking the floor to get it back to it's original position.

 

[rasit]

Welcome to forum......
+1 on previous posts. How long ago did you correct the drainage problem? Are you reasonably sure the settlement has stopped? The fact that the floor was able to move that much without cracking indicates that it is either reasonably thick, well reinforced or both. That would have been an awful lot of dirt that got washed out under the floor, where did it go??? If you are sure that the problem is now solved (no more settlement) there are basically four possible options:
1) If the floor has positive drainage and you can live with it, go ahead and epoxy. $
2) Add concrete over existing slab back to original grade. This may require special mix design of reinforced thin set grout. $$
3) Hammer out existing concrete, add stone and re-pour. $$$
4) Raise the floor back to the original elevation by mudjacking/pressure grouting. $$$

Options 3 & 4 are the preferred methods because they address any voids left under the slab and provide a solid foundation. You might want to go around with a hammer and listen for voids and then get a large hammer drill and poke some inspection holes (1"+) in the hollow sounding spots to see what your current conditions really are. If you are not so sure the settlement has stopped I would invest as little $$ into this project as possible because you will have future expenses to deal with.

 

[LegacyIndustrial]

I think you are an excellent candidate for slab jacking, call someone local to you for an expert opinion.

 

[JLeach]

Thanks for the inputs.

MDbeck: It slopes 4 inchs over 20 feet, and thats away from the doors.

rasit: The drainage problem was fixed about 1.5 years ago. I have had cars on it and it seems pretty stable. Im believe it has settled as far as it is going to.
Im not sure where the dirt went to. The basement has stayed dry, the other side of the house is normal, no sand washing out from under the walls? Dont know? As far as your options; if i am going to fix it i think I would do it right and hammer out existing concrete bring in fill then repour. Although that would be a lot of work and money. Your hammer test sounds like a good idea, as soon as i empty it out i will give it a try.

Scotty: If i jacked the slab im not sure how i would fill in the void to ensure it wouldn't happen again?

The more i think about it the more i want to cover it with epoxy and paint the side walls and hope for the best.

 

[LegacyIndustrial]

The contractor will handle everything.
It's quite a process.

 

[m.james]

I would fix it to prevent the slab from cracking and creating even more problems.