A common concern of many home buyers is whether there is any asbestos in the house, and if there is, is it in a condition that would be considered a health hazard? Asbestos, which has been identified as a carcinogen, is a naturally occurring fibrous mineral found in certain types of rock formations throughout the world. Asbestos fibers are strong, won’t burn, resist corrosion, and insulate well. These physical properties have made it a staple in architectural and construction applications. When the fibers are mixed during processing with a material which binds them together, they can be used in many construction products such as cement siding and roof shingles, vinyl floor tiles, ceiling tiles, textured paints or coatings, blown-in insulation, flexible fabric connections in ductwork, spackling compounds, boiler insulation, pipe insulation, caulking, putties, door gaskets on wood-burning stoves, and so on. (See FIG. 20-2.) The amount of asbestos in these products varies considerably, from approximately 1 percent to 75 percent.
Asbestos-containing material in the home doesn’t necessarily pose a health risk. Asbestos materials become hazardous only when due to damage, disturbance, or deterioration over time, they release fibers into the air. Airborne asbestos fibers can be inhaled through the nose and mouth and lodge in the lungs. According to estimates by the EPA, every year 3,300–12,000 people die from cancer caused by exposure to asbestos. Of particular concern is asbestos-containing material that is sprayed or troweled or that has become friable. (Friable material can be crumbled, pulverized, or reduced to powder by hand pressure.) As long as the asbestos-containing material is intact, it does not pose a health hazard. If the asbestos material is not likely to be disturbed or is in an area where renovations will not occur, the EPA suggests that it is best left alone.
Many houses have old boilers that are insulated with asbestos. The insulation looks like a white plaster coating over the boiler shell.
- Some roofing and siding shingles are made of asbestos cement.
- Houses built between 1930 and 1950 may have asbestos as insulation.
- Asbestos may be present in textured paint and in patching compounds used on wall and ceiling joints. Their use was banned in 1977.
- Artificial ashes and embers sold for use in gas-fired fireplaces may contain asbestos.
- Older products such as stove-top pads may have some asbestos compounds.
- Walls and floors around woodburning stoves may be protected with asbestos paper, millboard, or cement sheets.
- Asbestos is found in some vinyl floor tiles and the backing on vinyl sheet flooring and adhesives.
- Hot water and steam pipes in older houses may be coated with an asbestos material or covered with an asbestos blanket or tape.
- Oil and coal furnaces and door gaskets may have asbestos insulation.
Fig. 20-2. Locations of possible asbestos hazards in the home.
When the boiler is eventually replaced, it is necessary first to remove the asbestos insulation, even if the insulation is in good condition, before disassembling the boiler. Most heating contractors are not certified in asbestos removal. The job must be done by a qualified asbestos-removal contractor that has been trained and certified. Once removed, the asbestos cannot be thrown out like ordinary household garbage. A licensed industrial-waste hauler must take it, properly identified and contained, to a landfill that accepts asbestos.
Removal of damaged or deteriorating asbestos materials is not always necessary. In fact, it is the least desirable alternative because in the process it creates a considerable amount of airborne asbestos fibers that must be contained and removed. Depending on its condition, the asbestos material can be encapsulated by coating it with a sealant so that the fibers cannot be easily released. It can also be enclosed in airtight walls or ceilings that completely isolate and contain any fibers that become airborne. The decision whether to remove, encapsulate, or enclose deteriorating or damaged asbestos material, as well as the repair of damaged sections, should be made only by a certified trained professional.
Although most of the asbestos materials that had been used in construction are no longer being manufactured, various items can be found in many homes built prior to 1978. Identifying the more common types of asbestos material can generally be done in a visual inspection by home inspectors, asbestos-abatement personnel, or tradespeople who have frequently worked with asbestos material, and even by you. For example, in many older homes, the heating pipes in the basement or crawl spaces are covered with insulation that contains asbestos. The insulation on the straight sections of pipe, when viewed from an end, looks like corrugated cardboard. The angle fittings on the heating pipes are covered with an insulation coating that looks like plaster and is shaped around the fitting. If you see this type of insulation, look for torn, loose, crushed, or otherwise damaged sections. In many cases, it is not readily apparent whether building products and insulation materials contain asbestos. In those cases, positive identification of asbestos can be made by a qualified laboratory after analyzing representative samples of the material.