Tuesday, November 17, 2009

What about cracks?

Ask a Pro

Q. - I Have a couple of concrete slabs I would like to stain that were poured a couple of months ago.  Of course, they have cracked, is there concrete patch that you recommend that will be able to stain or will not stick out too much when stained?
Hello Robert,
A. -  If you have hairline cracks only (too small to stick a nickel or dime into), then you should leave them alone. The sealer should seal them off and they will only ad character to the slab.
   If they are larger cracks and must be filled then be aware that any patch material will stain differently from the concrete. Therefore the best course of action is to try out a few different patch materials that you can buy locally, to see which is a closer match, or which can have a second coat applied to bring it to a closer match.
   You will do this by making small sample test boards. You can use plywood or even stiff cardboard. Trowel on some patch material and allow to cure out for a day or so, until it has cured to one uniform color. Stain each test board, doing a section of 1 coat and a section of 2 coats on each, and also a small test section on each slab of concrete. After you have allowed the concrete stain to dry completely, have washed off the residue, applied the sealer to the test boards, and allowed them to dry, then you can wash down the test areas on the slabs and allow them to begin to dry. Once the test areas have dried down to being just damp, you can compare the test boards to see which will work best.