Dear James: I need to paint my house which has wood siding. The paint is in pretty bad shape. What is the proper way to scrape and prepare the wood surface so the paint will stay on longer and look better? — Missy D.
Dear Missy: You are thinking along the right lines. When people say they are going to paint their house, the painting phase is actually only about 10 percent of the project. The preparation takes, by far, the majority of the time and elbow grease. After all the preparation, the painting is the fun part of the job.
The proper steps when painting a house are washing, scraping, sanding, repairing, priming, and then finally applying the finish topcoat of house paint. No matter how good the quality of the paint is, you cannot expect it to adhere to old dirty, peeling paint. Paint must have a stable base.
First wash the walls to remove dirt, grease and extremely loose paint chips. If you use a pressure washer to clean the walls, you must be careful because a pressure washer can do considerable damage. If a powerful stream of water is shot directly at the siding, and it can force water into it and up under the siding. This is particularly true for two-story homes when are you directing the water stream up from the ground.
It is better to use the pressure washer on a low-power stream to distribute the cleaner over the walls and to later rinse them with fresh water. A solution of water, TSP (trisodium phosphate) and bleach (to kill mildew) is most effective.
You must cover any vegetation near the house. Also, first totally saturate the ground near house with water to dilute any solution that runs off. Environmentally-safe cleaners are also available, which I recommend.
Once the cleaning solution is on the walls, give it time to work. It is best to do this washing in the early morning or late evening when there is no direct sun and less wind so it will not dry too quickly. Use the pressure washer on low power again to rinse the walls with fresh water.
When the walls are dry, it is time to start the scraping. There are several scraping options: hand scraper, power scraper, chemical strippers, and heat strippers. Hand scraping is the most work, but it is still the most effective method to remove layers of old, deteriorating paint.
A good-quality hand scraper will have a handle and a tall knob. It is designed to be a two-handed operation. Always pull the scraper toward your body. This provides more force and less chance it will dig into the wood and damage it.
Select a scraper with a hard carbide blade instead of an inexpensive mild steel blade. The steel blades will dull quickly, making the job more difficult and increasing the possibility of damaging the wood.
Once you have all the loose paint removed, sand the surface. This serves two purposes. First, it provides a slightly roughened surface to which the primer can adhere better. Second, it will feather the edges along the spots where the old paint has peeled off.
Repair any bad spots with wood repair materials or even automobile body filler. Paint the surface with a good primer selected for the type of topcoat paint you will use.
Send your questions to Here’s How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com.