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How to fix a non-square slab?

skatiem's picture

Long story short:


We are residing our house with hardie board and it's been a long process (me and my husband for the most part). We decided to add a room on during the process. We hired a "concrete guy" for the slab. It wasn't square, off by about 3.5" on the outside corner.

Anyway, we were able to frame out the room using 2X6s instead of 2x4s, but there was no slab underneath the sliding glass door to bolt it into. Plus, it looks bad where the house hangs over the slab. We are trying to figure out how to build a new frame for concrete to fix it. If the frame is flush with the edge of the house, how do you pour in the concrete and ensure that it spreads evenly throughout? Do we build the frame larger than the edge of the house and chip off the extra after it dries?

Thanks for any tips on helping make this headache easier!

By "frame for concrete" I (post #207266, reply #1 of 2)

By "frame for concrete" I gather you mean forms for pouring concrete.  But you can't pour concrete into a 3.5" thick form and expect it to spread properly. 

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

So you're trying to fill in (post #207266, reply #2 of 2)

So you're trying to fill in where the slab is out of square? Your pour would  be to fill a triangle with the wide end 3 1/2" wide? Whew? it can be done but it's really tough to do well. You woiuld have been way better off if you had squared the slab then saw cut the excesss but that's hindsight. Even now I'd prefer to move the long end of the wall back so it's square and cut the slab off otherwise you're in a for a long battle.

Answer these questions and I'll tell you what to do next.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.