Need To Build Up Slab 3.5"

ruskent

I have a job I need to build up the height of an existing slab 3.5" then veneer pattern bluestone over it. Due to the access/finshed backyard pulling the slab out is not an option. What's the safest way to make up that height. Area is about 60sqft.

Anti-wingnut

Pour 3 1/2" of concrete on top of the existing would be the easiest. If you were worried about crack migration from the underlying slab, isolate with plastic, sand, foam, or a combination of those. Sixty square feet isn't much, why can't you demo? I've demo 'ed slabs in the middle of offices, on the 19th floor of 40 storey buildings. Do a saw cut, hammer and chunk the pieces out. Put in new compacted gravel, and then a high quality concrete.

bwalley

Just pour or pump 4,000 psi concrete on top of the existing slab, no reason to remove it, you could put bonding agent on top of the old slab first, won't hurt but not necessary.