Peeling From Wood Due To Moisture

Peeling From Wood Due To Moisture

Peeling results when wet wood fibers swell and move under paint, causing the paint film to loosen, crack, and sometimes fall off . There are several ways for water to reach painted wood:

•           Uncaulked joints allowing moisture to seep into adjoining wood surfaces

•           Worn-out caulking

•           Ice-filled or trash-choked gutters, causing moisture buildup under the shingles

•           Moisture-laden air trapped between interior and exterior walls (discussed later)

•           Damp basements

•           Painting boards that are too close to bare ground

•           Vegetation giving off moisture too close to the wood

•           Leaking roofs

•           Painting over wood damp with rain or dew

§          Power washing

•           Water leaks from household plumbing (either existing or a past leak that has been repaired)

Two common places where moisture enters the wood of a house are between the porch slab and the house foundation and through leaks in the roof. Sources of moisture may also be inside the home, as discussed later in the module. As new homes are built more tightly, the higher inside humidity concentrates in areas where it can still escape to the outside. Check for proper sealing and caulking of woodwork on the inside of the house.

Solution

The first step is to eliminate the source of moisture. Carefully inspect the outside of the building, paying special attention to window and trim areas and other joints. Remove loose or cracked caulking and repair with a quality product. You may need to install vents to relieve moisture, especially in the kitchen, bathroom, and laundry areas. Attic louvers, exhaust fans, and dehumidifiers are also helpful and should be used regularly year-round. A good rule is to provide one square inch of attic louver per each square foot of attic floor in the house. Ask the owner about any plumbing problems and have these corrected before proceeding with painting.

Power washing basically injects water into wood. It is particularly harsh on bare wood. One of the most common reasons for moisture in wood after power washing is allowing insufficient drying time. Let the wood dry for three to five days before recoating.

If moisture is rising from the ground through the masonry, waterproof the foundation with a specially-designed coating. If wood is touching the ground, remove that portion of the wood. Siding should come down no further than six inches above the ground.

Check the roof for signs of leakage and clean out gutters and downspouts.  If you suspect vegetation is a cause of peeling, trim it away from the siding.  If you can’t eliminate the source of moisture, try repainting the stripped wood with a thin coat of latex paint, which is more porous than oil or alkyd coatings.  A water repellent solution can also be applied to exposed wood.

Remove all loose paint with a scraper or wire brush, down to the bare wood, if necessary.  Sand rough surfaces.  Seal all bare wood with a primer and allow it to dry for one or two days before applying the topcoat. 

Use two coats of topcoat, which doubles the life of the paint.  High quality acrylic latex or alkyd exterior paints are available in a wide variety of sheens.  The right product for your application is generally determined by the environment in which the coating will have to perform.

Peeling from moisture on siding can be corrected by inserting small plastic or aluminum wedges or shims under eash board where it is nailed.  Insert between the nail heads.

This article prepared by Rick Anderson of 604-PAINTER call: 604-PAINTER in the Vancouver area for all your painting needs.