If you have a little crack in your outside stucco, you can repair it—and you should, or you may wind up with more serious repairs down the line.

Q: My house is 64 years old and has its original stucco on the exterior. One exterior wall has a hairline crack with paint peeling away on both sides. Is there an easy and fast method to repair stucco before the rains come, and is it a chore I can do on my own?

A: Good news: based on your description, your crack does not seem to be caused by the foundation sinking. I would have encouraged you to seek a foundation specialist if you had discovered larger cracks and symptoms, such as sticky doors and windows. As it is, this is work that any handyman can do. And since this is a critical job, you were wise to be careful. If rainwater penetrates behind the plaster, you might be in for a bigger problem.

You can repair stucco using a variety of commercially available products. Some are designed to fix larger gouges and holes, while others are specifically designed to heal cracks, as you describe. Quikrete, for example, provides a textured (sanded) acrylic caulk that is both easy to apply and effective.

The first step may seem counterintuitive: widen the crack with a cold chisel and hammer to at least a quarter inch. The crack’s edges should be perpendicular to the wall. Back trim the crack, if possible, so its base is slightly wider than its top. Then, remove any leftover material from the go using a wire brush.

Using a standard caulk gun, apply the stucco repair compound along the crack. As you work, trowel the patch to match the surrounding stucco finish. Allow the patch to cure for 24 hours before painting it with a water-based paint that is preferably the same color as the house’s outside.

Despite having cured, the finished object may feel malleable to the touch. The suppleness attests to the repair’s strength. If the wall changes considerably in the future, the patch will adapt rather than break apart. You may be certain that rainwater will not be able to infiltrate behind the stucco now that the fracture has been properly repaired.

Remember to leave stucco repair to specialists to ensure correct sealing and to avoid extra damage.