We got any concrete experts?

[Joe Celenica]

The concrete floor slopes to one side in my 12 x 24 garage. I like to wash cars during the winter in my garage so I won't freeze my balls off. I would like to to pour a new floor so the water runs to the middle and put a drain in the middle of the floor.

Now here's my questions: Can I pour 4" of concrete on top of the existing slab without putting any stone down first? Do I need to tie in with the existing slab with rebar? Ceiling height is not an issue. I don't really want to dig the existing floor up, just pour on top of it.

 

[Daryl in Nanoose]

I know one thing is the extra weight of that extra concrete. You have no way of knowing if the earth below will handle the extra weight.

 

['the epoxy floor guy']

I would say if the existing floor is in very good condition I would say DO IT. Install I would recommend 5" of 3500 psi concrete.

I would Install #4 (1/2") rebar @ 24" oc / both ways. NO need to use Fibermesh.

After installing the floor in order to get the best quality concrete I would:

Add as little Water as possible when pouring the concrete
Use a Cure and Seal, sprayed on with a garden sprayer, after you have finished it to the final state.

Keep off for 7 days with ANY heavy traffic.

If the floor is cracked / sinking / settling in any significant way I would STRONGLY suggest busting out and removing the old concrete.

ps. I would recommend at least a 1/8" per foot of 'slope' to the floor drain.

When finishing the floor make sure it is NOT higher than the surrounding concrete.

I have probably seen 3 floor drains IMPROPERLY installed for every ONE done correctly.