Inman

Recurring wall cracks mystify

Q: I own a 1950s fixer-upper. Above every door and window I have cracks that run to the ceiling or between doors. When I recently painted a hallway, I patched and taped the crack using the instructions in a home repair book. The cracks were back within six months.

I have been told that the house has an excellent foundation. Most of the cracks seem to follow the framing in some way. I really would like to paint the rest of the house, but I need to know how to get rid of the cracks first. Do I need to call in a professional, or can I do it myself?

A: Sometimes we get questions that leave us scratching our heads a bit. We think we know the answer, but rather than base our answer on assumptions, we engage in an e-mail exchange to find out more information.

This question was one of those. Our e-mail correspondence went something like this:

“We’re pretty sure this job doesn’t call for professional help. But we need a little more information to steer you in the right direction. If you’ll answer these questions, we’ll be better able to suggest a solution.

Our question: When you did the patching, exactly what did you do to patch the cracks?

Her response: To patch the cracks I widened them a bit, then filled and taped them. After it dried I sanded it smooth. I just used spackle and tape that I purchased at a hardware store.

Our question: Are the walls Sheetrock or lath and plaster?

Her answer: Sheetrock.

Our question: Do you know what type of soil you have? Is it heavy clay?

Her answer: Well, let’s just say that if I wanted to throw some pots I could mine the clay from my backyard.

Our homeowner is dealing with the bane of homes built on clay soil. The six-month gap during which the cracks returned tells us that soil expansion and contraction is probably responsible.

Water doesn’t percolate very well through clay. In the rainy season, clay absorbs water and expands. In the summer, it dries out and contracts. The regular expansion and contraction is causing movement in the framing of the home, which in turn causes the cracks in the walls.

The weakest parts of a platform-framed house are the openings — the doors and windows. Cracks in these areas are common. We’d like to be able to say that we have a failsafe cure, but we can’t.

We do, however, see some hope. You’ve followed the right procedure to fix the cracks and prepare the walls for paint. “Vee-ing” out the cracks to get good purchase with the patching compound and taping the cracks for reinforcement prior to finishing is the way to do the job.

We think your patching materials should be upgraded. If you used paper tape and regular Spackle from the can, we suggest you step it up a notch. For your next try at patching those cracks, use fiberglass mesh tape and quick-drying powdered joint compound. Durabond 45 or Durabond 90 are products we’ve had success with over the years. Both the tape and the mud are available at home centers and most hardware stores.

Premixed Spackle or joint compound dries through evaporation of the water in the mix. The Durabond products harden through a chemical reaction and are tougher than regular joint compound. Fiberglass mesh tape is stronger than paper tape.

You’ll find that you’ll need to cut the mesh with a utility knife, whereas the paper just tears off the roll.

Follow the same procedure using the different material. Vee out the cracks, fill the voids, apply the tape, and finish the patch smooth. Depending on the movement in your house, changing the patching material may eliminate the cracks or at least delay their reappearance.