You know the feeling. You walk onto a job site ready to work and think “This is going to be a simple gig.” But it’s not. You encounter something unusual – a problem surface or a substrate that’s difficult to paint. But don’t worry, it’s possible to tackle those “head scratcher” surfaces and still make a profit on the job.
Here are eight obscure, but not uncommon, surface situations that can be a painting contractor’s nightmare and solutions for painting them.
In an ideal world, all wallpaper would remove easily, and painting would be a breeze. But we all know this isn’t always the case. If you encounter wallpaper on a job, the first step is to try to strip the wallpaper from the surface using a concentrated wallpaper stripper. If the wallpaper is truly stuck to the surface and cannot be removed, you can paint over it with proper surface prep.
Remove any loose pieces and sand lightly so the surface is even. Then prime the entire surface with a high-adhesion water-based primer before applying your topcoat. The primer acts like a glue, sandwiched between the wallpaper and the topcoat. It seals down the wallpaper and creates a surface to which the topcoat can adhere.
More common in residential jobs than in commercial jobs, slick and shiny wood paneling requires some simple prep work for a perfect finish. If there is a surface design, or lines between each sheet, be sure to fill with a good spackling or patching compound. Let dry and sand as needed. Wipe the surface clean with diluted mineral spirits or paint thinner, and prime with one coat of shellac-based primer before topcoating. A shellac-based primer will seal the porous wood surface and cover any knots in the wood paneling, preventing them from showing through the top-coat. And because shellac-based primers do not require presanding and are ready to recoat in just 45 minutes, you will save time on the job.
I’ve personally encountered this obscure surface. As much as we tried cleaning the cabinets, no cleaner would get rid of the smell. As luck would have it, I ran into a Zinsser rep at a trade show, and he suggested coating the inside of the cabinets with shellac. I decided to test this solution on the worst smelling cabinet. I coated the interior with a thin coat of shellac and let it sit overnight. The next day I stuck my head in the cabinet and said, “Wow, this is incredible.” Sure enough, a thin coat of clear shellac on the interior of the cabinets was what I needed to get rid of the nasty odors. I finished the rest of the kitchen soon after that.
The hard, slick, nonporous surface of fiberglass doors provides very little gripping power for paint. If not properly prepared, paint can crack, peel or chip right off the surface.
To provide secure adhesion on fiber-glass doors, especially those in high traffic areas, clean the surface first with mineral spirits. Then apply a maximum-adhesion water-based primer that is formulated to adhere to hard, slick, non-porous surfaces. These primers cure fast and accept difficult topcoats like epoxies. They are ideal for high-traffic light-commercial areas, such as restaurants or the entrance to office buildings.
It’s never a good day when you find stains from tar, grease or creosote on the job. The best way to tackle painting these stains is to start with a heavy-duty cleaner and degreaser to remove any remaining stain residue. Next, prime the area with a water-based primer before painting. The primer will seal the surface and provide maximum adhesion for the topcoat. Never use an oil-based primer on tar, grease or creosote since it would “rewet,” or reactivate, the oil-based stains.
If odors from the tar, grease or creosote are a concern, consider using a shellac-based primer. The natural resins in shellac block odors better than any manmade substance.
White exterior PVC piping from HVAC or electrical work can be a visual distraction on a building and may need to be painted to blend in with the rest of the structure. This is often the case on commercial buildings. Exterior PVC pipe needs a resin-rich product that will grip onto this slick surface and will withstand temperature changes. Using a water-based premium primer to grip to the surface is your best option before topcoating.
This rubberized material is most often used on roofs to protect between where the roof surface and the chimney brick lines meet. Black in color, EPDM flashing is common in industrial roofing. If a color change is required, the best way to accomplish this is to use a maximum adhesion, urethane-modified acrylic bonding primer that will bond the topcoat to hard, dense surfaces. They will stick and seal to the surface better than anything else. Follow up with an exterior topcoat.
Copper has long been used as a roofing material, and it is commonly seen over bay windows on homes. After years of exposure to the elements, it can acquire a patina, a green film naturally formed on copper surfaces. Some homeowners may not care for this look and request the area be painted.
To paint copper, sand the surface with a 180/220 grit sandpaper to scratch the surface. This allows the primer to grab into the metal and ensures proper adhesion. Then clean with a mild soap-and-water solution before priming with a primer developed specifically for clean metal surfaces. Copper is a very reactive surface, so it is important to use a product specifically developed for this type of metal surface. APC
Frank Glowacki is the director of brands, primers and coatings at Rust-Oleum Corporation.