Salt-damaged stamped concrete in a reader’s driveway. (Reader photo)

QThe driveway at my house is stamped concrete. When it was installed, the concrete was poured first. Then the stamp pads were placed on the wet concrete, creating the design. Then a powder was sprinkled over the surface, causing the various gray tones. Later, during a snowstorm, I put down rock salt. The salt ate away enough of the concrete to mess up the stamped design. Is there a way to repair or camouflage the damage?

Hyattsville

A

It’s relatively easy to repair salt-damaged concrete that’s a single color and flat and wasn’t coated with a sealer. Quikrete, Sakrete and other concrete-products manufacturers even make DIY-friendly products for this. Sakrete’s Flo-Coat Resurfacer (www.sakrete.com) and Quikrete’s Concrete Resurfacer (www.quikrete.com) both contain a mixture of Portland cement, fine sand and polymers that allow you to squeegee on a thin layer to give stained concrete a fresh top coat. For pitted concrete, options include Sakrete’s Top’n Bond Concrete Patcher, which you can trowel or brush on to even out surfaces with divots as deep as half an inch. And Quikrete’s Sand/Topping Mix can fill even deeper spalling.

The reader’s undamaged stamped concrete. (Reader photo)

But stamped concrete typically is sealed, which would keep any of these coatings from sticking. And even if there is no sealer, it would be nearly impossible to patch the damaged areas in a way that preserves the original texture and re-creates the original mixture of colors.

Given that you have stamped, colored concrete, “to be honest, it’s usually better to just live with it, unless you want to remove and replace it,” said Dan Amaro, chief estimator for Alcoa Concrete and Masonry in Hyattsville (301-699-9300; www.alcoaconcretemasonry.com), an installer that also tackles repairs. He recommended that you call for a free in-person evaluation and estimate on options.

If the concrete isn’t sealed, it might be possible to re-coat the entire driveway and give it a brushed surface. You’d lose the texture and varying color, but at least you’d wind up with a tidy look.

If that idea appeals to you, you can test to see whether the surface was sealed by dribbling on a little water and watching to see whether it beads up. With a sealer, it would. Do the test in an area without heavy wear from tires or damage from salt so you aren’t misled.

If you’re dealing with sealed concrete or if you want to get back to having an unblemished stamped driveway, Alcoa typically charges $2-$4 a square foot to remove the old concrete, with large jobs at the low end of that range. Installing new stamped concrete without added color costs $12-$14 a square foot. Color adds $1 or more, depending on the look you want.

We installed polystyrene crown molding in our high-rise unit, where walls are drywall and the ceiling concrete. The molding came only in lengths of about seven feet, so we had to glue sections together. We used caulk, but the seam opened so we repaired it with Dap paintable silicone. It still fissured. How can we fix it?

New York

Dap used to make a paintable silicone caulk that was mostly silicone but discontinued that product in 2008. If that’s what you used, there is no easy remedy because nothing other than silicone sticks to silicone, even the paintable type, a technical representative for the company said. Even if you were to scrape out all you could, some residue would inevitably remain. Painting the molding with a flat paint, rather than a glossy one, would make the joints a little less noticeable.

But perhaps you used caulk that’s really standard latex caulk with a little added silicone. Dap still makes that: Alex Plus Acrylic Latex Caulk Plus Silicone. If you were to scrape that out, you could wipe off the joint with paint thinner and probably get a surface that other things would stick to, the Dap representative said.

Derek Thompson, co-owner of Crown Molding Solutions (800-315-6311; www.crownmoldingsolutions.com) an online retailer of polystyrene molding based in Cleburne, Tex., recommends using three caulk and filler products during installation: construction adhesive to glue the molding to the wall, painter’s latex caulk to fill any gaps behind the molding where it butts up to the wall and ceiling, and spackle for the joints in the molding itself.

Spackle, not caulk, is the best product for the end-to-end joints because it doesn’t noticeably shrink and is sandable, he says. Caulk, which shrinks more and can’t be sanded, works better for the seams against the walls and ceiling because it remains flexible and keeps its grip as those surfaces expand and contract with changes in temperature and humidity. If the caulk shrinks there, it isn’t a problem because you expect to see joints anyway.

In a new installation where two pieces are needed to span a long distance, Thompson recommends spreading a bead of construction adhesive on the lower edge of the first piece and a little spackle on the mating end. “Spread it like butter,” he says. Press the piece in place. Then add the adhesive to the second piece and press it into place. Use a caulking tool, a discarded credit card or other flat implement to wipe off any spackle. Don’t worry if some remains on the face of the molding; you can sand it smooth (with 320-grit sandpaper or a sanding sponge) once the spackle dries.

Thompson sells installation kits with the products he recommends, including Dap DryDex Spackling (www.dap.com). The Dap representative warned against using spackle with polystyrene molding — she said it wouldn’t stick. But Thompson and Scott Klemroth, owner of another online retailer of polystyrene crown molding, So Simple Crown in Carlsbad, Calif. (760-804-3949; www.sosimplecrown.com), said this is the product they use and recommend. “I’ve been doing this 15 years and I’ve never had problems,” Klemroth said. Told of the Dap representative’s advice, Thompson said sticking might not be the critical issue, since the spackle just plugs gaps and isn’t a surface coating.

In a situation like yours, where buttering the ends isn’t an option, Thompson suggested buying the spackle in a toothpaste-type tube rather than in a tub. The needlelike tip on the tube package will help you squeeze the material into the gap — once you clean out as much of the old caulk as you can.

Have a problem in your home? Send questions to localliving@washpost.com . Put “How To” in the subject line, tell us where you live and try to include a photo.