How to remove asbestos cement shingles

Asbestos-cement shingles are made of Portland cement and asbestos fiber formed under high pressure; they are hard, durable, and noncombustible; and are available in various designs, colors, and textures, including both uniform-thickness and tapered-butt shingles.

Ordinarily, asbestos-cement shingles require little maintenance. However, some shingles, especially in the lower courses, may become broken or otherwise damaged and need to be replaced. When purchasing shingles, it is advisable to obtain a few extra for this purpose, because it may be difficult later to match those which have been in┬áservice a number of years. Paint is not usually applied to asbestos-cement shingles, but a change in appearance may be accomplished by using resin-emulsion or rubber-solution paint, provided the manufacturer’s directions are carefully followed.

Exposed metal parts of a house, such as gutters, downspouts, screens on windows, flashings, fastenings, and electrical conduits, should be kept well-painted to avoid staining wall surfaces.

Dust and soot deposits may be removed from asbestos-cement shingles with soap and water or a solution of trisodium phosphate applied with a stiff fiber brush. The wall should then be thoroughly rinsed with clear water.

Deeply embedded stains which are not readily removed scrubbing with soap and water require special attention. Caution should be observed in using acid solutions. The use of rubber gloves is recommended, and clothing should be protected. Copper stains may be removed by a 5-percent solution of acetic acid or ordinary white vinegar applied by brush and followed by rinsing with clear water. Rust stains may be removed by a 5-percent solution of phosphoric acid or a 2-percent solution of oxalic acid, rinsing with clear water after application. Brown stains caused by contact with unpainted wood during construction may be removed by a good commercial abrasive cleaner or an oxalic acid solution.

Fresh paint spots can be removed from asbestos shingles by carefully wiping them with a cloth soaked in turpentine or other paint thinner. Dry paint spots can be scraped off with a knife and wiped with paint remover. Oil stains are difficult to remove completely. Repeated applications of a volatile solvent, such as carbon tetrachloride, will help to reduce the intensity of the stain. Asphalt and tar stains cannot be completely removed, but wiping with turpentine or other paint thinner will reduce the intensity of the stain.