How to Avoid Moisture-Related Paint Problems

Chronic peeling paint on the interior or exterior of your house is usually the result of moisture migrating through the walls and against the back of the paint film. Eventually, this causes the film to crack and peel. As long as the moisture continues to move through the wall, the paint will continue to peel.

How to Install a Vapor Barrier

One way to prevent moisture from migrating through your walls is to install a vapor barrier. But you can’t add a first-rate vapor barrier without removing the drywall or plaster from the interior surface of the walls—which is impractical, unless you plan to gut the house as part of an overall renovation. However, you can add a somewhat effective vapor barrier by painting a room with two coats of acrylic latex paint, which forms a continuous, flexible barrier that keeps a lot of moisture from moving through an exterior wall.

How to Improve Ventilation

The best way to reduce the moisture level in any room—and reduce the amount of water vapor that moves through the wall and, in turn, reduce paint peeling—is to establish better ventilation. Because the bathrooms and kitchen generate the most water vapor, they should be outfitted with exhaust fans to dump the moist air outside. Portable dehumidifiers or a central dehumidifier can also take a lot of moisture out of the air. They do cost a lot to buy and operate, but in the long run they save you money.

How to Remove Mildew

Paint failure isn’t limited to peeling paint on the exterior of your house. Interior paint can also fail by breeding mildew, especially on ceilings in moist areas. To remove mildew:

  1. Wash the surface with a mixture of mild detergent, 1 gallon of hot water, and 1/2 cup of household bleach.
  2. Rinse the surface with clean water.
  3. When the surface is dry, prime it with a stain-blocking primer followed with a coat of mildew-resistant paint.

How to Fix Peeling Paint on Wood Siding

To fix peeling paint, first eliminate (or reduce) the moisture in the room behind the paint, as described above. Then:

  1. Scrape off all peeling paint with a paint scraper.
  2. Once the peeling paint is removed, feather the edges of the nonpeeling paint with an orbital sander. Start with 100-grit, followed by 150-grit, sandpaper. Brush off the sanding dust.
  3. Apply a primer to the scraped and sanded sections. If removing the old paint exposed some knots in the wood siding, cover them with a stain-blocking primer after the standard primer is applied.
  4. Cover the primed sections with a topcoat of paint, feathering the edges so that they blend in better with the old paint. Then repaint the whole side of the house (or the whole house) with another topcoat.

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