When I was a kid one of my summer jobs was painting and staining decks and cottages. I’d arrive in my little tin boat and spend a day scraping off peeling paint and stain, maybe sanding a few rough edges before slapping on a new coat of finish. Two days work, easy cash. After all, what’s so hard about painting, right? Pick your colour and get rolling, or brushing or spraying. Done and done — if you can make the decision.
But not quite. I bet most of the exterior paint jobs lasted a season or two—at best; more likely, the finish was coming off before Thanksgiving closedown. Unless you want to repaint every year or be left with a spotty, craggy finish, exterior painting requires both mental and physical prep work, as Katie at Besotted Cottage found out. Here’s the scoop.
Step 1: Wood Inspection
Before you argue with your spouse over which hue of green best matches the dog’s fur, trek down to the hardware store and purchase a $30 moisture meter. These simple-to-use (think of those BBQ fork thermometers) devices check the moisture level of the wood. If the wood is too wet, paint won’t adhere properly. As a general rule, if the wood has more than 16 per cent moisture, it shouldn’t be painted. If this is the case, wait until later in the summer, when the wood is dryer from summer sun.
Step 2: Scrape
Scraping is perhaps the most straightforward task. For really loose paint, a simple flanged scraper works well; for harder-to-remove surfaces, use a sharp hook-type scraper. Scraping quickly dulls the blade, so if you’re working with a large area, keep checking the blade to make sure it’s not dull, and keep scraping until the old paint is removed.
For really stubborn areas, you can use an electric heat gun, but make sure you’re wearing a proper face mask to prevent against inhaling dangerous fumes from old oil and lead paint. As well, be aware that a heat gun can burn the wood, so keep water on hand to douse any flames.
Also, a word of warning: don’t fiddle around with sandblasting or chemical paint removers. These are professional-level tools that can easily ruin the wood if you don’t know what you’re doing. If the job requires this level of removal, consider hiring a pro.
Step 3: Washing, Sanding and Priming
Once the old paint is removed, fire up the ole power washer for a quick deep cleaning. As the name implies, these washers are extremely powerful, strong enough to rip apart wood, so don’t set it to high and start blasting. The idea is to remove any surface dirt and leftover paint. Once finished, allow two or three days for the wood to completely dry before sanding.
Sanding smoothes the surface and removes any loose, splintering material, which is especially important if you’re going to be walking on the wood. For small surfaces such as windowpanes, a palm sander (electric or manual) works well; for larger spots, use a random orbit sander (rentable). To avoid clogging up the machine, start with coarse, 100-grit sandpaper, moving on to a finer grit (120-grit) as you sand down.
Once sanded, wood needs to be primed to protect against moisture. There are two main primer types: alkyd primer, also called “oil base,” is usually used on wood trim and siding, treated lumber and metal surfaces. Alkyd primers are good for blocking stains, can be diluted using mineral spirits, and usually dry within a few hours or overnight. Apply with a natural bristle brush.
Acrylic, or latex primer, is similar to alkyd primer and can be used underneath any type of paint, even oil-based paint. Unlike alkyd primer, acrylic primer can be diluted using water and—the real benefit—has a reduced drying time, about four hours max.
Step 4: Picking Paint
Finally, time to get painting. But what’s better for exteriors, oil or latex? The answer used to be oil for its durability, but the quality of latex paints (and primers) has improved to the point of equality, with latex leading the pack for its ease of use and better environmental properties. Moreover, some contractors believe oil paint chokes wood, not allowing the material to breath and making it prone to moisture problems whereas latex allows moisture to pass through without causing the paint to pull away from the wood and peel or crack.
I’ve been using the word “paint” but really I’m talking about paint or stain, and when it comes to exterior wood, stain is usually your best bet for two reasons: one, it allows for the natural beauty of the wood to shine through, showing off the grain patters; but even more importantly, stain tends to penetrate deeper into wood whereas paint just coats the outside. Unlike paint, however, oil-based stain tends to stand up to exterior abuse better than latex-based stain, but if you prep the wood properly, the difference between the two is negligible.
The combination of stained wood with painted accents (windowsills, trim, and so on) is timeless, so consider adding some splashes of colour.
As for choosing a brush, there are two basic types: those made with natural bristles, used for applying alkyd or oil-based paint; and those with synthetic bristles, which can be used to apply all types of paint. As for quality, look for tapered ends (the centre bristles should be slightly longer than those at the edge to help lay down the paint smoothly. Also, choose a brush that is at least half-again as long as it is wide (e.g., the bristles on a two-inch-wide brush should be at least three inches in length).
For size, a four-inch brush with tightly packed bristles, about ¼-inch thick, is best for exterior painting, and an angled one-inch sash brush is great for painting trim and window frames. Lastly, don’t skimp on quality. Well-made brushes create a deep, smooth finish that naturally fends off mildew and dirt.
Step 5: Are you sure you want to do this?
Unlike indoor painting, exterior jobs require a lot of work (especially if you’re up on a ladder all day) and require about a week’s worth of dry days and nights. Depending on the size of the job, scraping, sanding, priming and painting can take up to a week, with three or four days of drying time.
Depending on where you live, the best outdoor painting weather is spring or early fall. The middle of summer might seem dry, but the hot, humid weather creates bad conditions for the paint—it simply won’t dry in high humidity; and in extreme heat, paint will dry too fast, causing uneven drying and even wood warping— to say nothing of the painter.
If it’s a small job, like refinishing a deck or painting a garage, this is certainly doable for most seasoned DIYers; if it’s painting an entire house, hire a pro and don’t waste your holidays.
