Renovation-Headquarters Banner


Overspray With Paint Sprayer

Question: My first attempt with an airless sprayer for siding resulted in a little overspray of the oil-based primer (Sherwin-Williams) on the shingles. I assume that weathering will eventually remove most of it. Is there another way to speed the process? I tried plain power washing without success. Can garage-floor cleaner (or any TSP based cleaner) be used with pressure washing?

Answer: I will assume you are talking about asphalt shingles. The asphalt is oil based as is the paint, and because of that it is unlikely that any cleaner will remove the paint without damaging the shingles. It is also possible you might smear the paint rather than remove it, which would probably be worse than the spots. Be careful with the pressure washer on the shingles, the small stone particles on the shingles are important, the pressure wash can easily remove them.

Question: I agree about there not being a simple solvent to dissolve the paint without attacking the shingle (I'm a retired chemist).

I did consider that a quick hit with a towel dampened, but not soaking with VM&P naphtha might get the surface paint off before attacking the shingle. However, the risk of that approach is that it might cause a smear of the paint, which would probably look worse than the fine speckles from the spray.

My other thought was more along the lines of something that would denature the paint (such as TSP) or cover it up. The shingles are black. Is there an asphalt-based paint I could spray? In other words, something like a thinned version of roofing caulk?

The affected area is not large. I had plastic sheeting about 18 to 24 inches up from the eaves. One can see the outline of the tape that was used to keep the plastic from blowing about and about one shingle width above that. A suitable flat black paint would help blend the white primer with the black shingles. Worst case, I might use flat black Rustoleum, but a purpose-made paint would be better.

Answer: With respect to painting the shingles, my concern would be that black comes in many shades and gloss factors and that if you don't get the black right, it may look worse than the current situation.

You might consider the possibility of using a liquid black roof seal (available at the big box home improvement centers) and thinning it down. No damage to the shingles, it is only the match that would be of concern. Black comes in many shades and gloss factors and that if you don't get the black right, it may look worse than the current situation.