Slab therapy

[rice rocket]

So my 24x24' slab for my detached garage is in pretty bad shape, it's settled probably 3-4" in the back corner (land slopes down from the front of the garage to the rear), 1-2" in the front corner, and the other front corner is heaved so the garage door can't close fully.

Lucky for me, the walls are block and doesn't sit on the slab.

Obviously I'd like to get away without spending a bundle, and I've been receiving these things in the mail about backfilling the slab by drilling a hole and pumping their "proprietary formula" in (I'm guessing is some structural foam of sorts). Problem is my slab doesn't seal to the walls (1 cm gap all around), so I assume they won't be able to create any pressure to lift the slab until they seal that gap and I'll be charged out the **** to do that.

I will be digging a French drain out in front to combat the source of this problem, but any other solutions to re-leveling the slab? I'm not after a sparkling surface that I could eat off of, but I'd like my garage door to be able to seal in the winter, as I'd like to eventually insulate it.

I suspect there is no rebar as it's a pretty old house (1920s, garage probably in the 50s?).

Thanks for any tips.

 

[fteufert]

I have the same issue, with a garage the same age. Before my garage burned down, the door closed on the blacktop, and now it is right inside the blacktop.

The blacktop is actually fairly level.

I too have on area of my floor that is hollow, and sinking.

All I want is my door to seal tightly, and not have water running in my garage,

Any ideas?

 

[rice rocket]