Preparing Interior or Exterior Surfaces for Painting
Preparing your walls, whether exterior or interior, for accepting paint is just as important as the actual painting, and especially when there is any type of unsafe lead paint to be eliminated, prep work is crucial. As a side note, if you are working on an older house and suspect there could be layers of hazardous lead paint covered up under newer paint, you should definitely contact a professional, as the removal will need to have special attention. Although the techniques used in prepping your surface prior to painting will vary depending on the specific surface or the project, there are some basic things you need to do no matter what you intend to paint.
First get rid of any dirt or fragments, including spider webs, from the surface. If you are prepping indoors, then it's a good idea to give the wall a thorough wash down prior to applying primer and paint. If you are painting an exterior surface, be aware that long stretches of accrued weathering can cause paint to bubble, crumble or chip. Outdoor surfaces should be thoroughly power-washed with a high-psi sprayer to remove dirt and any loose material. If the surface is particularly dirty or hasn't been painted in a very long time, then you may need to scrub the exterior surface with a wire brush and commercial detergent, or water and a mild bleach solution.
Once you have removed everything that doesn't belong on your newly painted wall, you've reached the caulking point. If the surface has been caulked before, then scrape away the timeworn caulk before applying new caulk. Use extra care around windows and doors to maintain a suitable seal against the weather. For much faster application, trying using a caulk gun with your caulk; don't prime your surface until your caulk is completely dry and hardened. If your exterior surface requires it, scour and sand the outside surfaces until a perfectly smooth and fresh result is achieved. If you are painting a wood surface, use wood filler to fill any existing hollows or spaces. Before painting windows, thoroughly inspect the area directly around the window panes for absent or unattached putty, and replace with a good grade of putty, allowing it to dry thoroughly. The wood putty should have a paste-like texture, and for the easiest application use a special putty knife. In rare cases where you are trying to remove an especially heavy buildup of paint which has been on the surface for decades, try using a propane torch with a special burner tip to sweep the flame evenly over large areas, and a scraper with a very long handle.
When your surface is as perfect as it can be, it's time to apply your primer. Whether you use a roller or an airless (if outside) make sure you use the correct nap, or the correct tip, and cover all surfaces thoroughly. Let your primer dry completely before you apply the final color paint coat. No matter how well your surface is prepped, you will probably still need to apply two to three coats of paint, and one to two coats of primer. Preparing your surface properly, then applying the best primer and paint will give you a finish you are proud of for many years to come.