When painting a wood-sided house, you may come across problem areas that need special attention before you can continue. Though this step takes effort, troubleshooting paint problems can save you time in the painting process and help extend the functional life of your home’s wood exterior.
Exterior wood is susceptible to numerous problems caused by moisture. You can prevent moisture problems by taking the following steps:
Moisture problems include algae, mildew and lichens. Here’s how to identify and resolve these problems before you start painting.
Algae can be identified by the green, red or brown spots that grow on damp surfaces that get extended periods of sunlight. To remove algae, wash the surface with a 3:1 bleach and water solution and scrub with a brush as needed.
You can prevent future buildups of algae by cleaning your home’s siding on a regular basis.
Mildew is a mold or fungus that usually grows in moist, shaded areas. To remove mildew, wash the surface with a 3:1 bleach and water solution and scrub with a brush as needed.
If your home’s exterior is susceptible to algae or mildew buildup, select a primer and paint that is algae- and mildew-resistant.
They leave roots, dirt and sap that work together to stain painted surfaces. To remove lichens:
Common wood exterior problems are caused by weathering, low-quality paints or inadequate preparation for painting.
Fading is caused by excessive exposure to light. Visually compare paint coloration at various locations on your home’s exterior.
Rub your hand across the siding to see if there is a fine powder, called chalking, caused by inadequate priming or overly-thin paint.
To remove the chalk, first clean the surface with a stiff brush using a Trisodium Phosphate (TSP) and water solution. Mix one cup of TSP per one gallon of water. Rinse the surface well when done.
Blistering refers to the tiny bubbles that form on the paint surface. These bubbles are caused by excessive heat or moisture.
If you find blistered spots, remove any sources of moisture. Then give the paint a few days to dry and recover; if it doesn't, pop the blisters with a putty knife.
If you can see the previous coat of paint under the blisters, the cause is excessive heat—a good reason not to paint in direct sunlight.
If you can see the natural surface of the wood under the blisters, the cause is moisture. Somehow, water has been trapped inside the siding or walls. The heat from the sun can actually draw the moisture through the walls and bubble the paint.
Check for condensation (collected water vapor) in the wall; if found, install vents in the wall.
For bathrooms, install exhaust fans to help eliminate moisture.
Also repair any drainage problems caused by the roof or gutters.
To repair the paint:
There are a number of different types of cracking paint:
Causes for cracking paint include applying paint over a glossy surface, not allowing an undercoat to properly dry before recoating, applying too many coats over time or coats that are too thick, or weather wear.
To repair these problems scrape, sand and prime the affected areas.
Applying paint in heavy coats can cause the paint to drip or run. Sand any drips smooth.
Inspect for flaking and peeling paint. Flaking paint is caused by painting over a dirty surface. Peeling is caused by painting a soapy surface.