Renovation & Design

ASK THE INSPECTOR: Asbestos tape can be covered, left alone

QUESTION: I have just discovered we have asbestos tape on our heating-pipe joints in an area where the ceiling is open. There are about 30 pieces of tape. Can I just tape over them with duct tape? What is the best way to handle this? If I hire a company to deal with this, can you recommend any reliable companies? Thanks, John Carey

ANSWER: Asbestos in common building products has been a concern for several decades, especially when renovations or age deterioration occur. But health hazards usually only arise when the fibres become airborne, so asbestos-containing materials on your heating ducts should be a concern only if they are worn. Fortunately, you can probably deal with old tape on a few heating ducts in your basement in a cost-effective manner without professional help.

Asbestos is a very fibrous material that has been used in countless products for decades because of its strength and fire resistance. Because it will not burn, it can be embedded in cement, wood fibre, vinyl and other building materials to improve resistant to fire.

Unfortunately, the natural configuration of the tiny asbestos fibres means they can become easily embedded in human tissue if inhaled. These fibres may remain in the body for many years and have been linked to several serious illnesses, including cancer. Because of this, efforts should be made to avoid any exposure to asbestos, and products containing asbestos have been removed from thousands of buildings.

There's probably little reason for concern with the small amount of asbestos-containing duct tape seen in your home. The small amount of asbestos fibres contained in the tape do not normally dislodge unless the material becomes worn or damaged. Still, with any material known to contain asbestos, care should be taken, regardless of how minimal the health risk may be.

If the material is intact and not torn or loose, leaving it alone or encapsulating it is probably the best option. But if the tape is loose and hanging from the ducts or ends are torn or frayed, then removal is recommended. When this type of tape deteriorates, the asbestos fibres have a much higher chance to become friable and airborne.

Because this tape is accessible, you may wish to try encapsulation. This means sealing the exposed surface of the asbestos-containing material to prevent deterioration and eliminate the chance of friability. This is often done by spray-painting the surface of the material, coating it with a thin layer of plaster and canvas, or other methods.

One method that is normally within the skill-set of many homeowners is to cover it with duct tape, as you've suggested. I normally recommend self-adhesive aluminum duct tape for this purpose, as it tends to adhere better and longer than traditional vinyl or cloth duct tape.

Before starting any encapsulation or removal of this hazardous material, proper safety precautions, especially breathing protection, are essential. Buying or renting a respirator approved for asbestos is absolutely necessary before doing anything.

The area to be remediated also should be isolated and sealed with polyethylene sheathing to trap any fibres that may become loose during encapsulation or removal. This will also make it easier to clean up the area, preventing contamination of other parts of the home.

Covering your head and body completely, often with disposable coveralls, is also necessary to prevent loose fibres from leaving the area and spreading throughout the home. If portions of the tape are removed, they should be collected and sealed in a doubled-up plastic garbage bag, and taken to a hazardous-waste collections site for proper disposal.

As reluctant as I am to recommend that homeowners can deal with potentially hazardous materials personally, the small amount of duct tape in your home may fall into that category. There are several highly competent environmental companies in our area that are specially trained to deal with these types of hazards, but costs for proper professional removal may be prohibitive.

Still, if you don't believe you have the skills or will to deal with this yourself, contacting a certified asbestos removal contractor for encapsulation or elimination is the next step.

Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the 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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