A reader is looking to repair or at least disguise this large crack in a Corian countertop. (Reader photo)

Q: Our Corian countertop developed a crack, I believe, after the stove that abuts it was moved. We have a very large countertop and it is really out of the question to replace it, because it is in good condition otherwise. Is there any way to repair or at least disguise the crack — which is, at its widest, about a sixteenth of an inch across?

College Park

A: A cracked countertop made of solid-surface material such as Corian can be repaired to look virtually as good as new by cutting a matching scrap piece into narrow strips and gluing them into a smooth channel that straddles the crack.

Winkhel Sahagun, owner of the Countertop Guru in Sterling, Va. (703-430-0007; gurutops. com), said that finding matching material for the patch isn’t as difficult as it might seem. Installers often give homeowners cutting-board-size pieces made from sections that were cut out for a sink or stove top. When a homeowner doesn’t have that, Sahagun said, he often finds something that works stashed in his shop or the shops of several friends who install countertops. “We share when we need a piece,” he said. Or if the style is still current, he orders samples or larger pieces as needed. As a last resort, he sometimes scavenges a section of backsplash from a side wall and the homeowner just paints there instead.  

Sahagun uses a router to cut a smooth channel along the crack, making it about half an inch wide and an eighth to a quarter of an inch deep. If he has access to the back of the counter, he glues reinforcing pieces underneath. Then he cuts strips of the scrap material to fit in the channel and stuffs them into the gap along with a special glue made by DuPont, the maker of Corian. If the room temperature is about 70 degrees, the glue dries in about an hour. Then he levels the surface with 80-grit sandpaper and goes through six progressively finer grits — 100, 150, 180, 220, 280 and, finally, 320 — to create a smooth matte finish that usually matches the surrounding countertop. If the countertop is shinier, he continues sanding with four even finer levels of a different abrasive, winding up with 1,000-grit. “When I’m done, it will look like the original piece,” Sahagun said.

He estimated that repairing a curved crack like the one in the photo you sent would cost $300 to $400 and take about three hours or less.

Tom Jones, a technician who works at FixIt Countertop in Hanover, Md. (800-349-4877; fixitcountertop.com), also said that repairing a crack in Corian requires cutting out a smooth groove and gluing in matching material, then sanding it smooth. He estimated the cost at $450 to $600.

Some handy homeowners tackle these repairs themselves. Besides using a router to cut the groove, it’s also possible to use a small rotary cutter, such as the ones made by Dremel. This cuts a narrower channel, which you could stuff with slivers of matching countertop material and suitable glue. The website solidsurface.com sells adhesives matched to many Corian colors, as well as in a clear formula, for $42 to $48 a tube.

If you don’t have matching countertop material but do have a current style, you can get up to six free sample pieces by visiting the DuPont website.

Q: I had a roof leak, which I fixed by having a new roof put on. Even though the ceiling below the leak didn’t suffer a lot of damage, a shadow shows up on it. It seems to look wet, but the paint is not peeling. The shadow seems to come and go. What is it and how do I get rid of it?

Herndon

A: If you’re not sure whether the ceiling is damp, it’s possible that it’s simply stained in a way that’s more noticeable when the light hits in a certain way. Test with a moisture meter. Lowe’s, for example, sells General Tools & Instruments’ Digital Moisture Meter for $30. When the ceiling looks wet, compare the reading you get there with one from a ceiling you know to be dry. Or press a sheet of paper to the troubled area and check whether the paper darkens, a sign of moisture.

If there is moisture, ask the roofer to come back and check the flashing on all exhaust pipes, skylights, chimneys or other things that extend through the roof. If the roofer refuses and you’re not up to crawling around in the attic, call a home inspector. (Then, insist that the roofer come back if a leak is found; if necessary, you can check the roofer’s license and file a complaint through the Virginia Department of Professional and Occupational Regulation.) Be aware that water leaking at a flashing doesn’t always drip directly down. It can travel along a rafter or the underside of the roof for some distance first.

The attic inspection should also include checking the insulation over the stained area of the ceiling. If the insulation is waterlogged, it obviously needs to be replaced. If it’s black, whether dry or moist at the time, that’s a sign that an air gap in the ceiling, perhaps around a light fixture or over cabinets where the space above wasn’t boxed in, is letting warm indoor air leak into the cold attic. Or there could be a vapor barrier improperly installed. Warm air holds more moisture than cold air, so as this air cools in the attic, moisture condenses and allows mildew to grow, making the insulation black. Enough moisture could even be condensing to cause the ceiling to become damp, especially when the indoor air is especially humid. The moisture could also be activating stains that are water-soluble.

If there are air gaps, plug them with caulk or other materials, depending on how big they are, then see if the dampness returns.

Once you are sure you have solved any moisture issues, press on the drywall or plaster to make sure it still feels solid and tightly fastened to the ceiling joists. If it’s spongy, you will need to cut out the damaged area and patch. (Cut along the middle of the ceiling joists so you can fasten the patch to solid wood above.)

If the ceiling is still okay, paint it with a stain-blocking primer. Oil-based primers used to be the only reliable way of blocking water-soluble stains, but today there are water-based primers that do the job, such as Kilz Max, $34 a gallon at Home Depot. (Regular primer won’t do, because water-soluble stains can seep through.) When the primer dries, repaint the ceiling.