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Prepriming on Site  

Instead of buying factory-primed siding, many builders prefer to buy unfinished siding, and to prime the siding on site before installation. That way, they have more control over the process, and can be sure the primer is applied thick enough. The work is best done under a roof. Bob Lipovsky, president of Kingston Construction in Fairfax Station, Va., likes to back-prime the siding on site. "First, we prime everything that's not going to be visible - the back, the ends. Then, when we get it installed, we prime the front," said Lipovsky. He has found from experience that if the front of the siding is preprimed, then handling it gets messy. "You don't want to prime the part that's facing you and make a complete mess. When you're handling this stuff, you want to put it right up." According to Mark Knaebe, from the USDA Forest Products Laboratory in Madison, Wis., "Ideally, you should back-prime with a water repellent, such as Dap Woodlife." He says that research has shown that a water repellent is better at resisting water entry than an acrylic primer, and less likely to trap moisture in the siding than oil-based primer. Dominick Lubrano of DPL Custom Builders in Williamsburg, Va., likes to prime both sides of the siding before installation. On a recent job, he took the time to put on two coats back and front, because "that way, you know what you get. Ultimately, it's up to the homeowners to decide. I tell them the benefits." But it's certainly not an easy way to go. Lubrano watches the weather for ideal painting temperature - 45 to 50 degrees - and pays attention to the cleanliness of the workplace. Storing the primed siding becomes a major issue. "We had to build drying racks for 8,000 linear feet of siding to store the lumber between coats." Lipovsky agrees that drying set-ups take up a lot of space (see photo). He recommends spacing the boards just enough so they're not touching, but air can still get to them. At a new home site, says Lipovsky, it's sometimes possible to rig drying racks on tarps in a basement, but it's rare to find enough indoor drying room on a remodeling job. Wayne Whitelock of Calais, Vt., prefinished the red cedar clapboard for his own house by dipping each board in a site-built trough filled with oil-based stain, and drying the siding on indoor racks. He says the system worked well. The only problem was that he ran short of prefinished siding before the job was over. A small portion of the siding was installed undipped, and received a coat of brush-applied stain after installation. Eight years later, Wayne can spot the difference. "The siding we dipped is absolutely flawless, but the hand-painted siding is starting to lose its color. Dipping it really does make a difference." -M.S. Return to article.