Q&A: Painting Asbestos Shingles

A.Bill Feist, an expert on finishes in Middleton, Wisc., responds: Since asbestos-cement shingles do not expand and contract with humidity changes like wood siding does, they hold paint very well. If the asbestos-cement siding is already painted and the paint is in good condition, clean the siding and then use a high-quality acrylic latex paint. Dirty siding will require a good cleaning (a detergent wash followed by power washing and thorough drying) to remove chalk and dirt.

Priming may not be necessary if the old paint is in good condition (free from peeling, cracking, flaking, etc.). However, if the old paint is glossy, or there are bare spots, it may be best to prime first. Use the primer recommended by the manufacturer of whichever acrylic latex paint you use. Be sure to apply two coats of topcoat paint, since two topcoats can often double the life of the paint job.

If some of the siding is deteriorated, showing loose fibers or broken edges, you may have to take special precautions. Aggressive scraping or sanding of loose paint is not advisable, since this could release asbestos fibers. If you anticipate replacement of damaged siding, you should check with your local authorities to determine any regulations for proper handling and disposal of asbestos-containing material. If you are not well trained in the potential dangers of asbestos, you should not disturb any of the siding.