SHELTER Magazine

Only Online - SHELTER May 2006

Preparing Wood Surfaces
Coatings Protect Door and Window Trim against Rot

by Tim Stephens

Many customers today are familiar with wood damage caused by rot and often see it in areas like casings, doors and window trims. The best way to avoid rot is to protect any and all wood surfaces with a protective coating. According to, "current estimates show that replacement materials, needed to repair damage caused by rot alone, account for nearly 10 percent of U.S. annual wood production."

Homeowners rarely have all day to spend on home improvements and often search for the easiest and simplest methods to keep their homes looking fresh and clean. Restoring door and window trims with decorative coatings is a long-term, relatively speedy option to refreshing well-worn surfaces in the home. To get the best results, customers can follow a few tips when restoring these areas.

  • Ask them to consider what color they would like to achieve once the coating dries
  • Remind them outdoor coatings are not to be used indoors and vice versa due to different chemical compositions and properties. It can be quite dangerous to mix or match in these areas
  • Encourage them to test these treatments similar samples of scrap wood to ensure they achieve the desired results
  • Direct customers to search for a product that is flexible, that will accommodate moisture and temperature changes by letting the vapor escape as conditions vary
  • Remind them that if the stain doesn't allow the wood to breathe, it can detach from the surface and begin peeling

Another factor is the reapplication; all products and surfaces are different, and this can become a time-consuming project and annual chore. You should direct busy customers to products that require low maintenance.

Before starting the coating process, the surface must be prepared. The degree of preparation needed will depend upon the age of the trim. Newer trims won't need much preparation aside from sanding. Older surfaces will need to be sanded first to remove the old coating or paint. Finish this process using 80 to 120 grit sandpaper. Pressure-washing is not recommended on these surfaces because is difficult as it can cause problems with doors and windows. Thinking only of the inside and outside surfaces and forgetting the inside and outside surfaces is a common mistake when coating a door. Another helpful tip is to recommend removing the door from its hinges and tape-off or remove all the hardware before beginning. While the undersides of these areas are not visible, the weather will certainly find and ruin it quickly if left untreated.

In preparation for the coating, remind customers to clean the surface thoroughly with this method:

  • Wet surface with clean water
  • Wash with two ounces of 100 percent tri-sodium phosphate (TSP) or phosphate-free substitute plus one quart of liquid bleach in three quarts of water
  • Let the solution sit on the wood for 15 to 20 minutes. During this period, scrub the surface with a hard bristle brush
  • Do not let the solution dry on the wood - keep it wet
  • Rinse the cleaning solution from the wood with clean water thoroughly

Again, leave three to four days for the area to dry prior to applying the wood coating.

Weathered wood with blue fungi or rust from nails may be treated after the surface preparation by applying a solution of four ounces of axalic acid crystals in a gallon of warm water. This solution should sit on the affected areas for 15 to 20 minutes before the final rinse with clean water. The area should be left to dry three days before coating the surface with a finish.

It is also important to remember that doors and windows have a lot of nooks and crannies. Before applying a coating, always encourage consumers to consider filling big spaces with a bit of caulk first, especially with panel garage doors.

When working with woods classified as tropical hardwoods, it is a good idea to wipe the surface with acetone prior to applying coatings, as these woods often have a higher natural oil content. When applying the treatment to doors and window trims, there are a few other considerations to take into account. As mentioned before, these areas often have many cracks and crevices; to fill in those spaces it is suggested to apply coatings with a long-haired natural bristled brush to ensure all of these areas are sealed. Proper application includes cross brushing (applying against the grain) which helps to fill these crevices and then on final strokes apply in the direction of the wood grain.

With the right product, preparation and technique, door and window trims can frame and lighten up a home in a new setting. When followed correctly, these steps can bring out the beauty and full potential of the home. By taking the right precaution and using the right materials, customers can preserve their doors and windows as a showcase of natural beauty for decades to come.

Tim Stephens is the communications manager at Sikkens Decorative Coatings.