Ask the Builder: How do you repair drywall?

I was removing an ugly ceramic tile backsplash in my kitchen. Some of the drywall paper came off with the old glue. It looks horrible. A home center employee told me I have to put in new drywall. This can’t be true. Is there a way to repair this so the wall is once again perfectly smooth?

— Shelly B., Siesta Key, Fla.

I’ll never forget the first time that happened to me. I was removing large sheets of thin wood paneling that had been nailed and glued over unpainted drywall. What a mess I had! The second time it happened to me, I was stripping off wallpaper in a bathroom. The hanger hadn’t primed the drywall with the proper sealant to prevent the wallpaper glue from bonding to the drywall paper.

But, the advice you received from the home center employee is completely wrong. You don’t have to replace the drywall. I’m going to describe how to repair it. It’s a shame that so much bad advice is dispensed each day inside those big-box stores.

The common drywall that’s found in many homes is made with fairly high-tech paper; you’d be surprised how thick it is. You can see it if you look closely at a cross section of drywall after it’s been cut or at the end of a piece before it’s installed.

The side of the paper that faces into your room and the other side that touches the wet gypsum at the factory both are made to resist the water that’s in the finishing compounds and the wet gypsum. But the center part of the paper will react violently if water reaches it.

If you’ve ever tried to patch drywall where the facing paper is torn off, exposing the core of the paper, you’ll quickly discover that the water in the patching compound almost always causes bubbles and blisters to form. The more you pop them and recoat them, the faster they return.

The first step in making a blister-free repair is a razor knife. You use this tool to trim any partially peeled up paper around the edges of the damaged area. You must have crisp cut lines all around the damaged area with no peeling paper.

Once you’ve done that simple step, you should coat the brown inner-core paper with an oil-based sealer that dries quickly. You can purchase spray cans of these primers, or you can brush on clear or white shellac. Just be sure that whatever sealer you use, it doesn’t contain any water. You can even use leftover oil-based paints.

Be sure that when you apply this sealer you paint or spray over the edges of the damaged area onto the undamaged drywall paper. You want to seal the thin edges of the drywall paper, too.

Once the sealer has dried, you can skim coat the area with regular drywall compound. The area that needs to be coated is probably less than 1 / 32  inch, so it’s not very thick.

To speed the repair process, you might consider using the setting-type joint compounds. These are powdered products that you mix with water. They come in various setting times. If you use a fast-setting one, you can apply two coats of the compound in less than 30 minutes.

To get a silky smooth finish, be sure to use the topping compounds that come in the buckets. These products really do finish smoother.

Tim Carter is a columnist for Tribune Media Services. He can be contacted through his Web site at www.askthebuilder.com.

 
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