|Scraping works best for removing paint from flat surfaces. Make sure the scraper is sharp, and apply even pressure as you scrape in one direction; then scrape at 90 degrees. Shaped scrapers such as triangles and ovals make it easier to get into corners and to scrape rounded profiles. Do not apply pressure when scraping hardboard. For really tough jobs, such as hard or metal surfaces, try a two-hand scraper. After scraping, feather-sand the edges of remaining paint with a medium-grit sandpaper.|
Whether painting or staining exteriors or interiors, wallboard or siding, if you remember these basics, you'll be fine:
- Prepare the surface carefully.
- Always use primer.
- Select the right paint for the right surface.
- Invest in good tools.
First things first: If you are dealing with an already painted surface and suspect the coating contains lead, hire a specialist to remove it unless your team has lead remediation training and experience. If you know the paint was applied after 1978 (when lead paint was banned), start looking for peeling paint, mildew and stains.
When old paint is cracking or peeling, you should remove it through a combination of scraping, wire brushing, sanding, power washing and chemical removers. A heat gun designed for paint removal may be used for old paint and varnish on exteriors.
|Exterior and interior surfaces should be cleaned with detergent and warm water applied with a rag or sponge before painting. Particularly rough or dirty surfaces might require scrubbing with a bristle brush or even power washing (only outside and never on softwoods such as cedar). After a thorough rinse, let the surface dry completely before priming.|
Keep in mind that loss of adhesion might be a sign of moisture behind the paint, says John Stauffer, technical director of The Rohm and Haas Paint Quality Institute. In addition to removing the paint, you need to identify the source of the moisture. Stauffer says common sources are gaps under windows or next to doors or chimneys, which usually can be fixed by removing old, cracked caulk and applying fresh caulk, which should be allowed to dry overnight.
Other signs of moisture intrusion include water stains and mildew. First identify and eliminate the source of the moisture. Then clean the surface, using detergent and warm water on stains, and bleach and water on mildew (see sidebar). Even if no stains and mildew are present, you still should clean the surface. After washing, rinse with clean water and let the surface dry.
Prime all the time
|A good primer helps paint or stain adhere, provide a uniform sheen, block stains, and resist mildew and corrosion. For unpainted wood siding and trim, the Paint Quality Institute suggests a latex- or oil-based exterior stain-blocking primer.|
Whether you're painting a new surface or over paint, Stauffer recommends priming. Particularly inside the home, he says, a uniform appearance on the paint surface depends on the priming. Primer also helps the new finish coat go on easier and last longer. Even aged stucco, he says, should be primed to help prevent efflorescence and maintain appearance.
Primer should be thinned, he says, except with certain older air sprays. And while contractors always should follow the coating manufacturer's instructions, if there is a question, Stauffer says to err on the side of applying thicker coats rather than thinner.