Painting the exterior of a house takes a lot of time— you won’t want to do it again soon! The key to a long-lasting paint job is solid prep work, and here are 17 tips that get the job done.
A long-lasting exterior paint job requires top-notch surface prep. Here’s how to do it right.
1. CLEAN SIDING AND TRIM
Dirty surfaces won’t hold paint. Remove dirt, mildew, cobwebs and anything else that isn’t meant to be there. Do the cleaning in stages. Start by applying a solution of bleach, water and a cleaner such as JOMAX (a bleach activator), using a garden sprayer. Next, remove weathered paint and dirt using a pressure washer. Be careful, as you can easily damage siding and trim with a pressure washer. If you don’t feel confident using a pressure washer, a siding cleaner and scrub brush will do the job. Thoroughly rinse to remove any cleaner residue and let the surfaces dry.
After the surfaces have dried completely, scrape off any remaining loose or flaking paint. Applying new paint over flaking paint will cause it to peel far sooner than it should. Before scraping, pound in any nail heads that could nick your scraper blade. You can buy a hardened steel scraper ($5 to $10), or for about twice the price, you can buy a carbide scraper. Carbide holds an edge far longer than hardened steel. With either option, buy a couple replacement blades so you don’t have to sharpen as often. You can sharpen a carbide blade using a diamond stone.
3. REMOVE OLD CAULK While you’re scraping, check the caulking around windows, doors and trim. If the caulk is in good shape and still adhering, leave it in place. If not, dig it out with a 5-in-1 tool (shown), utility knife or putty knife. 4. SAND OFF RIDGES
After scraping, sand any sharp paint edges, blending them with the surrounding surface. If you don’t blend them in, the sharp edges will create thin, weak areas in the new paint. Brush away any dust created by sanding, and then rinse the siding and trim thoroughly.
5. REPAIR DAMAGED SURFACES
Don’t paint over rotten or insect-damaged wood. Even if it covers, the paint won’t last. Replace or repair any damaged wood. Fill nail holes and other small imperfections with exterior wood putty. Sand off excess putty after it’s dry.
6. CREATE A GAP BETWEEN TRIM AND CONCRETE
Boards that come in contact with concrete won’t hold paint for long. Water on the concrete wicks up into the wood, loosening the bond between the wood and the paint. To remedy this, trim any wood so that it’s about 1/4 in. above concrete.
7. KEEP SPACE BETWEEN TRIM AND SHINGLES
If trim or siding contacts the shingles, water will wick into the wood and the paint won’t last. Lay a 3/4-in.thick spacer on the shingles and cut any trim or siding to create a gap between the wood and the shingles.
Prime nail heads, putty and knots before priming the whole surface. These areas are more difficult to cover, so they need a little extra attention.
9. PRIME ALL BARE WOOD
You can get good results with oil or latex primer. For bare woods with a high tannin (a dark, natural pigment) content, such as cedar and redwood, use a stainblocking exterior primer. Stain-blocking primers prevent “bleed-through” of tannin as well as stains from old, rusty nails.
10. CAULK ALL CRACKS & GAPS
Caulk around windows, doors, trim and anywhere else water could get behind a painted surface. Use interior/exterior paintable latex caulk. Be sure to prime first; primer adheres to bare or slightly dirty surfaces much better than caulk.
11. DON’T FORGET THE THRESHOLD
The bottom of a wood doorjamb will rot prematurely if you don’t caulk the line where the threshold meets the jamb.
12. SEAL END GRAIN
When you install or expose new wood, seal any end grain with a paintable water repellent, such as WOODLIFE Classic clear wood preservative. Allow the repellent to dry according to the directions, then prime and paint.
13. KEEP VEGETATION TRIMMED
Plants that come into contact with your exterior walls hold moisture against the paint, which can lead to compromised paint and rotting wood. That means more repair work, more money and more frequent painting.
14. WAIT FOR GOOD PAINTING WEATHER
Avoid painting on hot days, in direct sun and in windy weather. Ideal temperatures for painting are between 50 and 90 degrees F. Temperatures below 50 degrees can prevent the paint from adhering to the surface properly. Hot weather, wind and direct sun all cause paint to dry too quickly, preventing adequate penetration of the primer and/or paint. It can also cause oil paint to blister. When possible, work in the shade, following the path of the sun throughout the day. Never paint when rain is imminent or right after it rains. Painting a damp surface can cause paint to bubble.
15. KEEP AN EYE ON YOUR PAINT JOB
Whenever you’re out doing yard work, check in on your paint. Look closely for areas of cracked or peeling paint, or wood that might be rotting. With a little spot maintenance, you can extend the life of your paint job by a few years.
16. EASE SHARP EDGES
Sharp edges won’t hold paint; there just isn’t enough surface area. If you install any new wood, be sure to give any sharp edges a slight round-over. It doesn’t take much; a single pass with a sanding block is usually sufficient.
17. DON’T STALL ON PAINTING
Primer loses its bonding properties with prolonged exposure to UV light. After priming, you have a window of time to apply paint. Check the label on your can, as the amount of time can vary among manufacturers. We checked with two major companies. One said that paint must be applied within one week; the other said anywhere from four to six weeks.
Four-Sided Hardened Steel Scraper Blade Two-Sided Carbide Scraper Blade