Tuesday Jun 06th, 2017


Why Older Homes Need A Designated Substance Survey Before Renovating

Anyone who has lived through a renovation can attest to the amount of fine dust created during demolition.  In older homes, especially those built before 1980, there is a chance that dust may contain hazardous substances like asbestos, which can threaten the health of your family and the contractors who are working there.

Most homeowners, and even some contractors, are unaware of the potential liability they face when renovating an older home. Aside from the obvious health risks from exposure to hazardous substances, the bigger issue is the legal liability and financial risk faced by homeowners who renovate before ensuring the work site is safe.

In some provinces, homeowners are required to get a Designated Substance Report (DSR) before demolition can begin, which is produced after conducting a Designated Substance Survey (DSS).  In Ontario, the Ministry of Labor conducts random spot checks and their inspectors may stop work on a renovation until a DSR is received. This can mean a delay of several days to take samples from the work site, send them to a lab for analysis and then write up the DSR, which may be 15 or more pages long.

Designated Substance Surveys

Who’s responsible for getting a DSS?

Surprisingly, the homeowner is responsible for determining if any hazardous substances are present through a DSS and if so, to inform all potential contractors as part of the bidding process.  And contractors who receive this information must pass it onto other contractors and subcontractors who are bidding for work on the project.  If the owner or any contractor fails to comply with this requirement, they will be liable for any loss or damages that result from a contractor subsequently discovering these hazardous substances are (or were) present.

Here’s an extreme example that illustrates a homeowner’s potential liability: An older home was renovated 20 years ago. One of the workers who renovated this older home has since developed lung cancer, which he claims was caused by breathing in asbestos or silica fibres during the demolition. He could file a lawsuit against the homeowner for not ensuring a safe workplace before the work began 20 years earlier.

Cost of a DSS

A full Designated Substance Survey will examine for 11 hazardous substances, and costs between $750 and $1,500 depending on the number of samples taken and sent to the lab for analysis. But only four of the 11 substances are likely to be found in older homes, specifically lead (found in some paints), mercury (in some thermostats) and silica (in some concrete or masonry) and asbestos. Since asbestos is the substance most commonly found, the homeowner can economize by testing for asbestos only.

Dangers of Asbestos

Asbestos was originally used because of its properties of heat and sound insulation and fire resistance. But the dangers of asbestos are now well documented and asbestos is only harmful when it is disturbed and its tiny fibres become airborne and are inhaled.

The health risks of asbestos became known in the 1960’s and 70’s. By 1980, many manufacturers voluntarily stopped incorporating it into building materials and home builders avoided using it. As a result, most homes built after 1980 are free of asbestos. But the Canadian government will not ban it completely until 2018.

Asbestos  may not be visible since asbestos fibres were often mixed with cement and/or plaster or woven into fabric or mats. Or it may be hidden behind a wall and will remain harmless if left undisturbed.

One of the most common places to find asbestos is in some types of plaster or drywall compounds used before 1980. The only way to be sure is to take small samples from around the home and send them to a lab for analysis.


If you live in a home built before 1980, the first step is to get a DSS done by an expert. If asbestos or another designated substance is found, you have two choices:

Leave it, but be careful not to disturb it. For example, if your walls have asbestos in the plaster, you may decide to live with it. But ‘do not disturb’ means if you want to hang a picture, don’t use a drill, use a hammer and a small nail. And don’t use a vacuum to collect the dust, which may actually spread it – use damp paper towel instead.
Have it safely removed. Especially if you’re about to renovate, hire a pro to get it safely removed and disposed of before the demolition begins. 

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