Renovation & Design

Caution must always prevail when working with asbestos

Question: I’ve been asked to demolish a building with some two-foot by eight-foot asbestos siding.What do I need to know about such removal?

Thank you, Larry.


Answer: Limiting damage to the older siding when removing it may minimize most of the health concerns related to this type of work. But due to recent findings of asbestos content in many building products, determining what the local municipality requires for the removal and disposal of asbestos-containing materials, prior to commencement, is critical.

When dealing with building materials in existing homes that contain asbestos, caution should be taken primarily when that product is removed or damaged. When such a material is present, and we are discovering more of these every year, it may be benign if left alone. Because most of the asbestos fibres are encapsulated by the products themselves, or other applied coatings, they have very little chance of being set free to cause problems. When the fibres become loose, or friable, they can enter the air in our living space and be inhaled by the occupants. If asbestos fibres are breathed in, in significant quantities, they can remain embedded in the lungs permanently. Over several decades that situation can lead to a potentially fatal type of cancer called Mesothelioma, or other health issues.

The main concern with demolition of any older building, or portions, is releasing embedded asbestos fibres into an enclosed space that will later be occupied. Most major renovations or demolitions will cause some of this to occur, but preventing anyone from inhaling this material is the ultimate goal. The initial concern is for the workers doing the demo. Taking precautions for you and other workers, with use of proper respirators, goggles, gloves, and disposable coveralls, is imperative. The next concern is to properly contain this material within a controlled environment. That may require completely or partially enclosing the work site with plastic sheathing, tarps, or other items to prevent friable asbestos from contaminating the surrounding area. Finally, cleaning up and proper disposal of any hazardous materials will be required.

Because you are working outside of a building to be demolished, there should be no chance of contaminating any current living space. Regardless, there may be local health and safety requirements to prevent releasing asbestos into the area, and the landfill or waste facility. Checking with the municipality when a demolition permit is obtained should answer these questions.

For specifics related to older cement-asbestos siding, careful removal may minimize any or all the major concerns. Especially if the siding has multiple layers of paint, the asbestos will be well encapsulated within the material, itself. If it is not physically cracked, crushed, broken, sanded, or scraped, there is little chance of friability. This thin siding was typically nailed along the top edges and lapped over the lower section, so minimal fasteners were used. If entire sections can be pried off without damage, and the nails pulled out, then disposal should be fairly simple. If it is in generally poor condition, with broken edges or missing sections, then more care must be taken during removal. Since this material is very rigid and thin it can be quite brittle and may easily break if handled roughly during demolition.

While you are certainly correct in enquiring about this type of siding removal, it is not the only building material that should be a concern during the proposed demolition. Any wall or ceiling covering that contains plaster, older drywall, or drywall compound may have a certain amount of asbestos content. Since all or most of the interior walls and ceilings will fall into this category, you may be in for a much more time-consuming job than anticipated. If the building is an older commercial or industrial one, especially with a T-bar ceiling, there may be even more asbestos-laden stuff to remove. Older ceiling tiles are also a potential source of this hazardous material. Finally, many older flooring products, especially vinyl tiles or sheet flooring, have an asbestos component but may be less of a concern. Especially with solid vinyl-asbestos floor tiles, the fibres are well embedded within the plastic, so removing them with minimal damage and as whole as possible should help. There still may be an added cost for disposal, so factoring that in to your budget will be required.

What you need to know before agreeing to demolition of an older building begins with finding out what materials in the building do, or may, contain asbestos. Following that up with use of proper personal protective equipment for all people involved in the work is the next step. Determining the requirements for precautionary measures, and added costs of disposal, is the last concern and should be investigated ahead of time with the local building officials in the municipality where the building is located.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the past president of the Canadian Association of Home & Property Inspectors — Manitoba ( Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at



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