Q: I just moved into an old house and will be setting up shop in the basement. The concrete floor is really dark and I would like to lighten it up before I move the machines in. What durable finish can I use?
A: You have several options, but we like water-based concrete stain the best. You can get it in a variety of colors, including white. It’s easier to work with than an oil-based floor paint and doesn’t give off dangerous fumes as does epoxy paint. Concrete stain won’t peel or chip off when you move your machines around because it penetrates the surface. Paint forms a film on top.
Before staining, the concrete must be cleaned thoroughly and etched to make it porous. Clean your floor with TSP (trisodium phosphate). If your state bans TSP ask a paint supplier for a substitute. Clean oil or grease stains with a degreaser. Thoroughly rinse away all the residue.
Etching abrades the surface of the concrete and allows the stain to deeply penetrate. Use either muriatic acid or phosphoric acid (your hardware store should have these) as directed on the label.
Acids must be handled with care. Wear full-wrap goggles, rubber gloves and old clothes while cleaning and etching. Dilute the acid by adding it to the water (not the other way around!). Make sure the area is well ventilated.
Triple-rinse the floor by spraying with a garden hose and brushing with a stiff broom; then allow the surface to dry completely before applying the stain.
Mix all the stain you plan to use in a large bucket and spread it with a 1/4-in.-nap roller in 3-ft.by 3-ft. sections. Cut in around the walls with a synthetic brush. Wait 24 hours before using the floor or putting on a second coat.