Eric Phillips on Asbestos in Older Houses…

Almost any house built prior to the 1990s will contain some asbestos. This WorkSafe BC link will show you some of the more common places and give an overview of asbestos in the home.
It is interesting that the diagram uses a relatively modern house as its example. Asbestos, as the miracle do-anything product, came into full prominence after our houses were built, but there will still be some asbestos used either during original construction or during subsequent renovations/maintenance. The most common places to find materials which may contain asbestos are in vermiculite insulation (one common brand name is Zonolite, which looks like small brown popcorn), “popcorn” textured ceilings (sometimes called Spray-Tex), duct tape (asbestos tape was used to seal joints on hot-air ducts and also on furnaces and fireplaces), asbestos-board siding, flooring, drywall & fillers, and electrical boxes. We had a local Grandview example where asbestos was found in the plaster as well but it was not clear if it was in the original plaster or came from post-construction renovations (filler with asbestos). The reason for the asbestos concerns is that once disturbed, the fibres will stay airborne for a long time and the long-term consequences of inhaling them will not be immediately evident. To confirm I was not misleading you, I talked to a carpenter friend who has been through the working-with-asbestos course and he gave a few examples. He had a job of re-placing some old flooring. The 9×9 tiles and the adhesives almost certainly contained asbestos. To avoid the cost of dealing with their removal, the tiles were left undisturbed and were covered with floor-leveling compound and then with sheet flooring with the edges sealed. An engineered wood floor could also have been used with the same sealing precautions.
How do you know for sure if there is asbestos in a material to be removed during renovation? Testing in the only way to know for certain. For example, I have some vermiculite insulation in my attic. If I simply wanted to increase the amount of insulation, I could have added more insulation on top but since I needed to move some to get access to wiring, I took some samples to a lab and had it tested. Although my insulation does not look any different from any other vermiculite I have ever seen, it did not contain appreciable amounts of asbestos. While on that topic, if you are planning a renovation, someone in our ad hoc group is completely renovating their house and therefore had samples analyzed but found the City would not accept self sampling and required sample collection by a certified testing group. This is contrary to the information provided on the City’s website.

Eric Phillips
“Amateur House Mechanic”, Grandview Heritage Group

7 thoughts on “Eric Phillips on Asbestos in Older Houses…

  1. A great idea to add this valuable information to the web site.

    It is easy to think of these house hazards as being from 100 years ago, since we are talking about houses 100 years old, but almost all of them have been renovated and updated numerous times right up to the present using hazardous materials..

    It is probably worth mentioning lead paint was legal and common into the 1970s and asbestos (including in ceiling tiles, drywall and drywall mud) commonly used in renovations as well as in newly constructed additions, was only completely banned in Canada in 1990.

    For example,

    Canadian Environment Law Association
    http://s.cela.ca/files/ASBESTOS%20FAQs%20_11.01.2012__0.pdf
    “The use of asbestos in Canada was common during the period between 1930 and the early 1980s.
    However, up until 1990 asbestos was also found in insulation made from the mineral vermiculite,
    specifically in Zonolite insulation, as well as in potting soil. “

  2. Bruce, do you know what the “appreciable” level of asbestos in vermiculite is considered to be? In other words, at what percentage does the stuff become hazardous and have to be treated as such?

      • I think the best way to look at asbestos is to think of it as a secured bottle of tiny glass shards. While the shards are in the bottle, they are harmless and you are fine. If you open the bottle and breath in or ingest any amount of them, it is bad for you. Many house hazards, for example lead paint and asbestos, are only a problem when they are able to be taken into the body by being transformed into small particles and inhaled or eaten.

  3. The City of Vancouver defines “asbestos-containing material” as containing more than 0.5% by weight in: http://vancouver.ca/files/cov/asbestos-policy.pdf This document details how vermiculite and other materials which contain asbestos may be disposed of. The COV recommends testing to avoid higher tipping fees and sets some restrictions on the material. There are a list of acceptable testing facilities on this site as well but be aware that there are precautions to be taken in sampling, both to avoid exposure and to ensure the sampling is precise. The certificate for my vermiculite insulation has expired (valid for 30 days) but was in the 0.1% range. Keep in mind that the Asbestos Network quotes OSHA as saying there are no safe levels of asbestos but allowing “permissible levels” of 0.1 fibre/cubic centimeter for industry and abatement work. WorkSafe BC recommends following ALARA principles – maintaining levels at “as low as can be reasonably achieved”.

  4. Thanks for that.

    I have also found this:

    Vermiculite insulation is considered to be asbestos containing if any amount of asbestos fibre is found within the sample according to WorkSafe BC OH&S Regulation 6.1(b).

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