How to Strip Years of Paint Off a House
What stands between an old house and new paint? Ten tenacious coats of the old stuff. But you can get it off
To penetrate and remove the 10 layers of paint on the siding and trim at the Winchester project, painting contractor Jim Clark (shown here) and his crew used a newly developed, non-caustic stripper that breaks the bond between paint and wood. Before choosing their approach, they considered several methods, detailed in the following slides.
From a distance, the house in Winchester, Mass., site of the 2002 - saboteamos.info TV project, was a picture of yellow siding and white trim. Closer inspection revealed a craggy clapboard landscape of cracks, chips, and flakes where 10 coats of paint, applied during the 80-year life of the house, were failing by degrees.
"The clapboards are cypress, I think—a full 10 inches wide and 7/8 inches thick at the butt," said TOH general contractor Tom Silva. "Beautiful wood in great condition, except that it won't hold any more paint."
Painting contractor Jim Clark concurred: "We could feather out the failed areas with scrapers and sandpaper before priming and top coating, but a year after we finish, the flaking and chipping could start again. So all the paint has to go. That means a lot of work, but when we're finished, we'll have a baby-smooth surface that will hold nice, even coats of paint for a long time to come."
Dealing With Lead
Stripping paint from any house built before 1978 raises the question of lead. Given the number of coats on the Winchester house, Clark had no doubt about the presence of the heavy metal. In the past, scraping lead paint required hiring a licensed—and costly—abatement contractor to remove and dispose of the lead-laced paint. But changed in Massachusetts in 2001, according to Jim Roberts, an environmental analyst with the state's Department of Environmental Protection: "Massachusetts adopted federal Environmental Protection Agency guidelines that reclassify lead paint residue from a residence as household waste. The idea is that if it is easier for homeowners to dispose of lead, they will be more likely to remove it from their homes." For Clark and crew, it meant that they could do the work—if they took the mandated safety precautions—and that all the paint they removed from the house could simply be bagged up and chucked into the trash.
(power sanding disk or clapboard sander)
Pros: Fast, efficient, leaves no residue on surface; relatively inexpensive (no chemicals to buy).
Cons: Only works on non patterned siding like clapboards. In inexperienced hands, can scar wood. Noisy; creates airborne dust that's a lead concern and requires a HEPA-filter mask. Some states require vacuum connection.
Testing Different Methods
There are three basic methods for stripping paint—grinding, applying heat, and using chemicals. All of them are hard work because the same binders that cause paint to adhere make it hard to remove. Clark and his crew considered using several different methods on the Winchester siding before making a final choice. As the slides to the left reveal, all these approaches have advantages and disadvantages. But every paint-stripping job is a little different, and past experience, along with some empirical testing, helped Clark decide what would work best for the Winchester house.
For instance, grinding—using power sanding disks or clapboard sanders—is very efficient on siding that's in good shape, but it generates lead-laden dust. Although the tools can be fitted with a vacuum hose, the last thing Clark wanted, in a cheek-to-jowl neighborhood like Winchester, was to release any lead-contaminated dust. "The work was scheduled for high summer," says Clark, "when everyone has their windows wide open. On top of the dust, there's the constant loud scouring noise the tools make."
Heat and chemical strippers were also given a try. The big downside of most heat methods is the risk of fire. "Any stripping contractor can tell you a story he's heard of a house burning down," says Clark. "A crew finishes at the end of the day, there's an ember under a dry clapboard...next morning, ashes."
Chemicals are less straightforward because of the different types. The old standard, methylene chloride, is effective but very nasty stuff. Also on the market are some "environmentally friendly" strippers, some of which work better than others. "It's unfortunate," Clark says, "but it seems that the least caustic chemicals are the slowest, and some of the orange-based products I've tried don't really work well."
(heat plate or heat gun)
Pros: Relatively fast, thorough, and inexpensive (no chemicals to buy).
Cons: Can release some lead along with smoke, so a respirator is recommended. Biggest danger, though, is fire (often delayed when an ember under a clapboard ignites).
Ultimately, the product that won the day at Winchester was a water-based chemical stripper called RemovAll. It doesn't attempt to dissolve the paint as other chemical strippers do but instead breaks the bond between paint and substrate. Clark adds, "The best thing about the product, as far as my crew and I are concerned, is that it's nontoxic. No gloves, HEPA filter masks or respirators, no safety glasses. Spray it on in the late afternoon, let it sit overnight, and by morning the paint comes off in sort of rubbery sheets. We scraped it off easily with long-handled, 3-inch-wide putty knives." Most areas of the building took two coats of the stripper—not surprising considering the multiple layers of paint. The price of the RemovAll—about twice that of methylene chloride —was, Clark feels, outweighed by its environmental benefits.
As luck would have it, when the house was three-quarters finished, Clark was shown a revolutionary tool that may change his mind about how he strips paint from here on. It uses infrared rays to heat up the substrate behind the paint, totally loosening its bond to wood or metal. "The Silent Paint Remover" heats to a maximum temperature of only 500°F—well below wood's immolation point. "Hold it over an area for 20 to 30 seconds, give it a quick scrape, and all the paint layers come off down to the bare wood. It's lightning fast," said Clark. "We'll use it on the front of the house and the garage."
As with all stripping methods that involve scraping down to bare wood, some sanding is necessary before the first coat of primer goes on. "Scrapers have a tendency to burnish the wood, making it too smooth and shiny to take paint," says Clark. "We always hit all the surfaces with a random-orbit sander and 80-grit paper to get good tooth for that first coat of primer."
Pros: Very fast (about 20-30 seconds exposure); low operating temperature won't ignite wood; removes all paint with one pass. Requires no mask, gloves, or goggles; inexpensive to operate (no chemicals to buy).
Cons: Not yet widely available; $395 initial cost.
Picking the New Palette
While the exterior paint was stripped, homeowners Kim Whittemore and Bruce Leasure searched for new, historically accurate colors for their Colonial Revival home. Kim consulted a book by Roger Moss called Paint in America: The Colors of Historic American Buildings (Preservation Press, 1994; ). It's arranged by house periods, with each section showing appropriate colors for an era. "It's like one of those 'idiot's guides' to whatever," she says. "I flipped to Colonial Revival, and there were lots of interesting choices."
Bruce and Kim narrowed the range to four color families: blues, grays, taupes, and greens. Armed with preliminary picks, they hit the streets of their neighborhood. "We didn't want to match, and we didn't want to clash with, any of the houses around us," Kim says. TOH master carpenter Norm Abram had this to offer: "Once a paint is on the building, it looks several shades lighter and brighter than what's on the postage-stamp-size chip you get at the paint store." The best way to gauge true colors is to invest in quarts of the shades you're considering, paint part of the building with each, then stand back and look.
After a trip to the local paint store, Kim painted test swatches of seven colors for clapboards and five for trim. "It came down to a final choice between stone gray for the body with cream-colored trim, or a greenish-gray with dark, bottle-green trim," she says.
Jim Clark helped with the final decision, painting a section of clapboard and window and shutter with each combination. "In the end, we chose the green-gray for the clapboards, cream for the trim, and dark green for the shutters," says Kim. "It was a lot of work, but you know, it took us a while to find the right house. Why wouldn't it take at least as long to find the right colors?"
(available in different formulas, depending on paint type)
Pros: Generally quick to apply and nonflammable. Can be sprayed or brushed on. Most dissolved paint adheres to proprietary paper, which is peeled off.
Cons: Mixed results, often requiring second application; paper is extra hassle.
Where to Find It
Napier Environmental Technologies
Delta, BC, Canada
Dumond Chemicals Inc.
New York, NY
Massachusetts DEP guidance for residential lead disposal
Infrared paint stripper