Until the 1970’s, when it’s use was regulated by government agencies like the Environmental Protection Agency and Occupational Safety and Health Administration in the U.S, asbestos was found in a wide range of residential construction materials, most notably pipe insulation, roofing, wallboard, flooring and ceiling tiles and electrical insulation.
Asbestos is a fibrous, crystalline form of several types of silicate mineral, chrysotile being the most common.
Asbestos has been recognized as a carcinogen since the 1930’s, particularly in lung cancer and mesothelioma, but it also causes other non-cancerous problems, including coughing, shortness of breath, lung infections, weight loss, and heart failure. Asbestos is only a hazard to your health when inhaled, so the asbestos in your home that can pose the most risk is asbestos open to the indoor air, such as pipe insulation or electrical insulation.
If your home has asbestos located where occupants are exposed to it on a regular basis, some form of asbestos removal remediation should be considered. Be aware, however, that attempting to remove asbestos can create a problem or make the existing problem worse; often the safest course is to isolate the asbestos from the indoor air by building an airtight enclosure around it, or, if it is in an out of the way area, leaving it as is.
Household exposure alone has never led to any documented cases of cancer dur to asbestos. Those most at risk are professional workers who are continually exposed to high levels of asbestos fibers, such as pipe fitters, shipyard workers, asbestos factory workers and workers at textile mills which manufacture asbestos cloth.
Where is Asbestos in the Home?
A home will likely contain asbestos in some form if it was built or renovated between 1920 and 1978. Here is a list of potential places asbestos could be found-
Hot water piping insulation
Fuse box liners
Heating system ducting
Sheetrock joint compound
Furnace door gaskets
Lamp socket collars
Electrical wiring insulation
Paper used as insulation around furnaces and built-in stoves
Roofing shingles and siding
Fireproof drapes and curtains
Testing for Asbestos Removal
Testing of indoor air for overall asbestos levels requires specialized equipment, is expensive, and is rarely done on private residences, except when asbestos has already been identified as present in the home through visual inspection.
The usual practice is a trained inspector visits the home and gathers samples, which are sent to a laboratory for analysis. Collecting samples yourself is not recommended, as you can easily release asbestos fibers into the air, to be inhaled by yourself or family members.
For example, getting a little bit of asbestos duct insulation inside of a heating duct will contaminate the whole house quickly. Contact a local testing service or asbestos abatement service for an inspection.
Inspectors will look for asbestos, wearing gloves, protective clothing and a HEPA respirator or dust mask. When they find possible asbestos material, they will dampen an area of the material with a spray bottle to prevent the release of fibers, and with a small knife cut away a sample patch. The sample is placed in an airtight vial for analysis later. The area around the material is carefully prepared to prevent more fibers from escaping, and the site is cleaned of any stray material.
Depending on the location and condition of the asbestos, you have several courses of action to do deal with it; enclosure, encapsulation, asbestos removal, or leaving as is.
If there is asbestos in your home but it is in good condition, with no fraying of fibers, and is not likely to be disturbed by occupants, then it is better to just leave it alone. Any abatement where none is required will be money wasted, and could also result in creating a hazardous condition where none existed before. But if the material containing the asbestos has fibers frayed and loose, or is located in a high traffic area of the house, then this is a hazardous condition and you should consider enclosure or removal.
Enclosure of asbestos is surrounding it with other materials or an airtight partition wall or ceiling; this method contains any loose fibers and is less expensive than removal. Heating ducts or pipes with asbestos insulation, for example, can be wrapped with lagging cloth tape, or enclosed in a soffit type structure. Any structure built around ductwork, of course, must conform to local fire safety and building codes.
Another method less expensive than removal is encapsulating the asbestos, which amounts to sealing it with a specialized encapsulant compound. Certain elastomeric vapour barrier wall coverings and high-quality latex paints can be applied by airless paint sprayer as encapsulants, as long as the materials containing the asbestos are in good condition.
Because encapsulation and enclosure both leave the asbestos in place, another benefit to using these methods is that you do not have the added expense of installing new insulation.
Complete removal should be the last resort for asbestos abatement. It is the most expensive, labor intensive, and takes the most time. As noted above, you also incur the cost of installing new replacement insulating material. It also poses a significant health hazard to those performing the removal work. The job is best left to experienced professionals who have the proper safety equipment and know how to remove the asbestos so as not to contaminate the other parts of your house.
On the positive side, complete removal also means a complete end to the problem. You never need worry about maintaining the encapsulation materials mentioned above or monitoring of condition of asbestos materials left exposed. Not only that, but any renovation you do in the future can be undertaken in complete safety. It can also add value to your home when it comes time to sell.
Nonfriable Asbestos Materials
Materials with asbestos that is embedded in another material so that fibers cannot escape into the air, such as roofing shingles and older vinyl sheet flooring, are referred to as nonfriable asbestos.
These forms of asbestos do not pose any health hazard when left in place undisturbed. Removal of nonfriable asbestos materials can, however be a health risk, since breaking, sanding or cutting may release fibers into the air. Rather than replacement, it is usually recommended to leave them in place and cover over them with new, nonasbestos materials when required.
With resilient flooring containing asbestos, many local building codes and regulations only permit certified asbestos contractors to do removals. It is best to only perform a removal in cases where the floor is broken in many spots, has de-bonded from underlayment, or is curled up at edges.
The alternative is to install new flooring over it. This involves preparation of the surface by applying levelling compound to low spots, or installing a layer of underlayment over it. The new flooring can then be installed on the old.
Photo by USACEpublicaffairs, Creative Commons Attribution