Do I tell my Ottawa contractor about asbestos before they bid?

Yes. Section 30 of the Occupational Health and Safety Act puts a duty on a project owner, and telling bidders what you know is the safe course even where that duty's reach is unsettled.

Section 30 of the Occupational Health and Safety Act requires an owner to determine whether any designated substances are present at the project site and to prepare a list of all designated substances found there. Asbestos is one of the 11 designated substances listed in O. Reg. 490/09, along with lead, mercury, silica and seven others. If work is being tendered, you must include a copy of that list in the tendering information. You must also ensure that any prospective constructor has received a copy before a binding contract is entered into. Section 30(5) makes the stakes clear: an owner who fails to comply is liable to the constructor and every contractor and subcontractor who suffers loss from the later discovery of a designated substance the owner ought reasonably to have known of.

How section 30 applies to a house you live in yourself is not fully settled. O. Reg. 278/05 gives owner-occupiers an exemption from the owner duties in that regulation, including the examination and written report requirement in section 10. Section 30 itself contains no residence exemption, and Ontario's guide to the regulation says section 30 applies to owners of residential properties who undertake projects. The exemption covers a home the owner or their family lives in, and a building of up to four units where the registered owner or family lives in one of them. A landlord who doesn't live in the building, a building of more than four units, and commercial property are not covered. If you are unsure where you stand, ask the contractor or the Ministry of Labour before work begins.

In practice: if your home was built before 1990, Health Canada identifies older building materials, including insulation, surface treatments, floor and ceiling tiles, roofing products and pipe insulation, as materials that may contain asbestos. Having a professional test suspect materials before you invite bids gives you a list to hand to every contractor and lets them price the same work. A pre-renovation inspection with asbestos testing runs roughly $250 to $1,300 depending on the size of the building and the number of samples, based on published Ontario contractor prices read in September 2026.

What to ask each contractor when they arrive to bid:

• Which materials in the scope do they consider suspect, and will they confirm the Type in writing once they assess friability and area on site?
• If the work may reach Type 3, have they given the Ministry of Labour inspector notice, and has the supervisor completed the Asbestos Abatement Supervisor Training Program?
• Where will the asbestos waste go, and has that disposal site agreed to accept it, as required by Ontario Regulation 347?
• Can they provide a current WSIB clearance?

Before you sign anything with this contractor, ask them directly: if suspect material turns up during the work that was not in the owner's report, what is their process for notifying the Ministry of Labour inspector, as section 10(8) requires, and for getting you a revised scope and price?