MISTAKE #5: Encouraging Premature Paint Failure
Never paint a surface that has any type of water or moisture on it. Make sure the rollers or brushes are 100% dry before using them.
Latex fights moisture problems better than oil. For areas that always seem damp, use latex paint. Latex paint lasts longer in damp areas. Latex contains no vegetable oils to attract mildew and dries with a more porous film than oil-based paint. This lets moisture escape.
If your house has a moisture problem that causes water to collect behind the wood siding, then no paint will stick until you address this underlying problem.
It is important to read the paragraph labeled “Surface Preparation” on the side of your paint can. One of the sentences will state that you should remove all dirt from the surface. A common mistake that several people make is they forget to wash the house prior to applying the paint.
Failure to properly wash the surface is the most common causes of premature paint failure. Most people merely rinse off the surface being painted and don’t really clean it.
Cleaning and rinsing don’t give you the same results.
Several paint manufacturers recommend that customers use a powdered commercial cleanser. There are several good soaps on the market to use. It is important that you use soap and water to properly clean the area that is going to be painted. The reason cleaning is vitally important is dirt weakens the bonding power of paint, especially the small dirt particles you don’t easily see. It also removes tree sap, airborne oils, bacteria produced oils and pigment chalk.
Chalk is formed by the natural breakdown of paint. Rub your finger across any paint that has been exposed to sunlight and the weather. Normally, your finger will pick up this chalk from the painted surface. This chalk will be the same color as the paint.
To understand why paint chalks we should explain to you how paint is made. Paint is mostly made from three different groups of materials: pigments, resin and vehicle. The resin enables the paint to stick to surfaces and it also holds the pigment together. The pigment is the part that gives paint it’s color. The vehicle, commonly called surfactant, is the part that makes paint a liquid. When paint dries most of the surfactant evaporates into the air.
Ultraviolet light from the sun and natural weather processes break down the resin. This breakdown then releases pigment at the surface. These pigment particles are just barely hanging on at this point. Rain can easily remove the chalk/pigment particles.
There is another benefit to cleaning with soap. The majority of latex exterior house paints are alkaline. Soaps are also alkaline. When you clean a surface and rinse it off, the washed area will be slightly alkaline. This helps the paint to bond even better to the surface. Use soap, water, a soft bristle scrub brush with a lot of sweat equity.
MISTAKE #6: Cutting Corners when Stripping
Stripping the whole house down to the wood surface is a lot of work. First start with energetic hand scraping. You can use various power tools to remove the remaining paint. Sand the entire surface until smooth. Even the most thorough scraping and sanding won’t remove the mold and mildew in old wood, but a cleaning solution containing a 1/2 cup of bleach and a 1/2 cup of tri-sodium phosphate in a gallon of water can help. Next, spray the house’s surface while scrubbing with a stiff-bristled brush. Let the formula do its work for 1/2 an hour before rinsing with a garden hose. It is not always recommended to use a power- washer as its streaming jets can damage old wood.
Let your house dry for one warm sunny day. Some paint contractors recommend treating the bare wood with a clear, water-repellent that you can paint over. This helps to prevent moisture penetration. If you choose to purchase a repellent make sure it is designed to help the wood swell less when it rains. Keep an eye open on the label for a preservative that kills mildew. This could possibly discolor the top layer of paint or cause wood to rot.
Repellents not labeled “paintable” may contain so much wax that paint won’t stick. It is a good idea to let the water-repellent dry for at least two sunny days before going to the next step.
If you have decided to prime, this would be the time to paint with primer. The main reason in using primer is for paint to stick better to the surface. Before you paint your final coat, seal window frames and door joints with latex caulk. We will be talking about caulking later in the report.
If you are painting over dark areas and patchy spots with a light pigment paint color you might need to apply two coats of paint so it completely covers the dark areas.
Finally, liquid sandpaper such as deglosser cleaners help prepare dirty, oily or varnished surfaces for better paint adhesion.