Q. I am on the board of our local recreation association. We operate an indoor swimming pool that is about three years old. The pool deck, which is about 2100 square feet, was supposed to have a “brushed finish,” but the surface grooves are inconsistent and sometimes not even visible. Now our members are slipping on the surface when it is wet. The surface also shows some discoloration and staining.
I've heard mixed feedback regarding the use of a mild acid wash to roughen up or etch the surface and create more traction. How can we best improve the traction on the pool deck, remembering that budget is always an issue?
A. Your best bet might be to do a light sandblasting of the surface. Blasting with beads or sand can give you a very appealing sand finish look. It's also easier to control how deep you go into the surface of the concrete.
Sandblasting will be more expensive than acid etching, however. Covering the pool would be necessary, and sandblasting indoors can cause quite a mess. Using tarps to isolate areas can be helpful.
Acid etching could work also, but acid is very unforgiving and can go too deep in some areas. If you choose to etch the surface with muriatic acid, be very careful to use the correct amount of acid to water. Also make sure to use rubber gloves, boots, and goggles and to protect anything you do not want to ruin, especially your skin and eyes.
Try it first in a small, inconspicuous area. When you brush the solution onto the concrete, it will begin to bubble as it reacts with the calcium in the surface paste. This chemical reaction, between an acid and an alkali, can give off very unpleasant fumes, so good ventilation is essential.
After scrubbing with a nylon brush, thoroughly wash the area. Let it dry and see how it looks. One of the drawbacks to acid etching an area of this size is that you cannot let the initial acid-water combination stay on the surface without washing it off, which tends to dilute the acid concentration as you move to the next area.
If you choose to use this method, start at the edge of the pool and work away from it, as the drainage indoors tends to be back toward the pool. This will help keep your rinse water away from the areas that you haven't etched yet. Also, check with your pool manager about possible effects the drainage may have on the pool water.
You might also look into some of the more user-friendly alternatives to muriatic acid. For example, Atlanta-based Safe-React (www.safe-react.com) offers a non-hazardous replacement that takes a bit longer but reportedly works well in an etching application.