Navigation

Removing sealer from patio

by Patrick Preston
(Castle Rock,Colo.)

Q. I had a colored concrete patio poured in my back yard.My Painting company(Kwal Howells)told me to put a sealer on it after it cured for about 60-90 days.After over 90 days They told me to use a product called Coronado Industrial floor coverings called Superthane Aliphatic Acrylic Urethane.It turned my concrete darker and put a glossy finish on it.When we got our first rain it made real dark cobweb like stains all over the place.It looks horrible.Thruout the winter it's all stained and blotchy looking.
My paint rep has tried citrus removers,Strypeeze,and we've tried laquer thinner.The thinner helped a little but it evaporates to fast.I also have trees and shrubs somewhat nearby that I dont want harmed.Sherwin Williams told me to try Bix spray on stripper, or xylene.I hate to use such harsh things but we're at our wits end.The patio has a somewhat rough broom finish.Any ideas would be very welcome.

A. It was a very bad idea to use a urethane sealer outside. Concrete needs to breathe to allow moisture to escape and urethane is a non-breathable sealer. Moisture coming up through the slab caused the sealer to fail and become spider-webbed and blotchy.

There is a product called SOY Gel that is harmless but will take the sealer off. It's a gel so it won't run off as you're applying it. It needs to sit on the surface for a while to give it time to loosen the sealer. The best way to use it, especially outside, is to apply it in the evening so it doesn't dry too fast. Spread it evenly over the surface, work it in with a push broom, and then cover it with plastic sheeting. Then power wash it the next morning.

SOY Gel is fairly expensive but it works and won't harm you or the surrounding plants. Right now it's only available online or at contractor supply stores.

The other option is too grind it off with a diamond grinder but this will take off the broom finish and leave you with a slick surface. This is the best method if you plan to overlay it.

Reseal it with a solvent based acrylic sealer for the best look and protection.