crackepoxygarage
I just bought a house which was built in 2007 (Seattle area). The garage floor has no drain or expansion joints. As a result, there are some cracks in the concrete. They are small.
I was wondering if it is too late to add expansion joints. Ultimately, I'd like to finish the garage with epoxy coating. I wouldn't want to see new cracks showing up on the floor after I add the epoxy coating.
Thank you!
There are stucco crack patch products out there. For lack of a better explanation, they are essentially sanded caulk:
Use that to fill in the cracks, then paint over with proper stucco paint (breathable latex).
You can use a diamond blade to cut drainage channels. Noisy and messy, but it works. You can (for reasonable sums) either rent a concrete saw or purchase a diamond blade for an angle grinder, as you prefer. You can purchase a concrete saw, of course, but the sums appear unreasonable to me for a one-time project.
With such a limited amount of water (no wetness entering other than on the car) you could probably just cut a grid and leave it at that, with the water collecting in the channels and evaporating. An approach with a bit more finesse would cut the channels a bit deeper under the middle of where the car sits so the water would tend to drain away from where you are walking.
If you wanted to put in a sump (seems over the top for this garage) you would carefully slope the channels to it. While the floor does not have a proper slope, if the channels do, the water moves off the "islands" of floor between the channels, and then flows to the sump. That is typically done with a guide rail that you support at the desired slope above the floor to run the saw on.
I don't think the water in any way affects the structural integrity of your house.
If you have adequate headroom you could also add a new layer on top of the existing slab, without breaking it up, though I don't think there's any real need for that.
The cracks are probably not related and not of any real concern.
Best Answer
You can cut expansion joints with something like this:
This is a walk-behind concrete saw that can be rented at most rental centers (I know that home depot has them).
After the joints are cut, fill them with a good polyurethane caulking.
I would wait until after you cut the joints before filling the existing cracks, as it's likely the work you're doing with the saw will result in vibration or "abuse" of the floor and might widen existing cracks.