Concrete slab over finished garage floor

[kma_97]

Hi all,

I have a finished garage floor (epoxy over concrete) but need to pour a 43 in x 23 in x 8 in concrete slab that would support a safe (1,100 lbs). It will be adjacent to an existing concrete ledge (about 8 in high) on one side.

A few questions to the pros:

1. Wire mesh? (I assume that it's a yes)
2. What do I need to do to ensure that the new slab will bond with the old one? (Scrape? Adhesive? Both/neither?)
3. Given that the garage floor is nicely finished, how do I ensure that the frame is reinforced while pouring and curing concrete, without damaging the floor outside of the area that will be covered by the new slab?

Anything else I should have asked, but didn't?

Thank you in advance!

 

[ConCretin]

I'll take a stab at your questions;

1. Wire mesh? (I assume that it's a yes)
2. What do I need to do to ensure that the new slab will bond with the old one? (Scrape? Adhesive? Both/neither?)

I'll answer these two together. I'd drill in rebar dowels a foot or two apart around the perimeter of the pad to keep it from moving if hit and some mesh or a few rebar to hold it together if it happened to crack. Honestly you probably don't need either but it's cheap insurance.

3. Given that the garage floor is nicely finished, how do I ensure that the frame is reinforced while pouring and curing concrete, without damaging the floor outside of the area that will be covered by the new slab?

You could build a rugged enough form to withstand the lateral pressure of the concrete without attaching it to the floor but you also need to hold the form down. You could use something to weigh it down but the simplest thing however might be a few Tapcon screws. You could fill the holes with a caulk that matches your floor color and probably wouldn't notice them.

Hope that helps. Good luck.

 

[kma_97]

Thank you!