Renovating an Older Home: Asbestos, Lead Paint and Old Wiring

Older homes in Ontario often contain materials that were common when they were built but are now recognised as health hazards. Asbestos was used in Canadian homes mainly before 1990, lead-based paint is likely in homes built before 1960, and aluminum branch-circuit wiring appeared in some homes in the 1960s and 1970s. If you are planning a renovation, the first practical step is to find out what is in the house before anyone starts opening walls or pulling up floors. Testing before demolition is not optional paperwork; it decides the order of work, the permits and who can safely do each job.

Why the age of the house sets the questions

The construction date tells you which hazards to suspect. A home built before 1960 probably contains lead-based paint somewhere, often on trim, doors and windows. A home built between 1960 and 1990 may have lead in its exterior paint. Asbestos was used mainly before 1990 in a range of materials, from insulation to floor tiles. Aluminum branch-circuit wiring was used in some homes in the 1960s and 1970s, and older wiring of any kind should be assessed before walls are closed. None of this means the house is unsafe to live in. It means the renovation plan has to account for what is inside the walls before they come down.

A useful first step is to gather what you know: the approximate build date, any previous renovation permits, and any records of past work. Then walk through the rooms you plan to change and note the materials you can see. That list becomes the basis for testing and for conversations with contractors.

Asbestos: where it hides and why testing comes first

Asbestos was used in Canadian homes mainly before 1990. It can be found in some vermiculite attic and wall insulation, in plaster and textured ceilings, in floor tiles, in pipe and duct wrap, and around older furnaces. It is a hazard when disturbed, because the fibres can become airborne and be breathed in. Sanding, scraping, cutting or demolishing these materials without controls releases fibres into the air.

Testing for asbestos before renovating is the only reliable way to know whether a suspect material contains it. A sample is taken by a qualified person and analysed in a laboratory. Do not rely on appearance alone; materials that look similar can have different contents. If asbestos is found, removal is done by trained asbestos professionals, not by a general contractor or a homeowner. The work area is contained, the material is removed carefully, and the waste is handled and disposed of according to the rules.

Vermiculite insulation deserves special mention. It is a loose-fill insulation that was used in some attics and walls, and it may contain asbestos. Do not disturb vermiculite insulation. If it is present in an attic or wall that a renovation would open, get advice before any work begins. In many cases the plan is to leave it sealed and undisturbed rather than remove it.

Lead paint: the pre-1960 risk

A home built before 1960 probably contains lead-based paint. A home built between 1960 and 1990 may have lead in its exterior paint. Lead paint is most often found on older trim, doors, windows, and sometimes on walls under newer coats. The hazard arises when the paint is sanded, scraped or burned, because that releases lead dust. Ordinary renovation dust control is not enough; lead dust is fine and spreads easily.

Before disturbing painted surfaces in an older home, have the paint tested. If lead is present, the work needs methods that control dust: sealing off the area, keeping surfaces wet while scraping or sanding rather than dry sanding or burning off the paint, and cleaning up thoroughly with appropriate equipment. Removal of lead paint is a job for trained professionals, particularly when large areas are involved or when the paint is in poor condition. A renovation contract should state who is responsible for lead-safe work practices and how waste will be handled.

Old wiring and aluminum branch circuits

Older wiring of any kind should be assessed by a Licensed Electrical Contractor before walls are closed. Aluminum branch-circuit wiring was used in some homes in the 1960s and 1970s. It can be safe if it is properly maintained, but connections can loosen over time and create a fire risk. Knob and tube wiring, found in even older homes, has no ground conductor and its insulation can become brittle. A renovation that adds insulation, new fixtures or new circuits can disturb this wiring.

Paid electrical work in Ontario must be done by a Licensed Electrical Contractor with an ESA permit. The contractor files the permit and arranges inspection. A homeowner may do electrical work in their own home only with their own ESA permit, but given the risks in older wiring, assessment by a licensed contractor is the practical first step. The assessment should happen before the renovation schedule is fixed, because rewiring can add time and change the order of work.

How discoveries change the schedule and the contract

Hazardous materials are usually found after the walls are opened or after testing is done. That is why the schedule needs contingency time and the contract needs a clear process for changes. A change order should be written and signed by both sides before the extra work is done. The contract should also say who arranges testing, who does removal, and how the work area is isolated.

A sensible sequence for an older home is:

1. Gather age and history information.
2. Test suspect materials before demolition.
3. Get the electrical assessment before walls are closed.
4. Build the results into the permit drawings and the schedule.
5. Hire contractors with the right qualifications for each hazard.

This order matters because test results can change the scope, the drawings and the price, and it is far cheaper to learn them before the contract is signed than after the walls are open. For a step-by-step view of the whole process, see how to plan a home renovation in Ontario.

Permits, contractors and who is responsible

A building permit is generally needed for structural changes, additions, basement finishing where walls or plumbing are added, and many other renovations. The Building Code Act, 1992 and the Ontario Building Code set the rules, and the municipality’s building department enforces them. Once a permit application is complete, the Building Code requires the municipality to issue or refuse a permit for a house within 10 business days, but incomplete applications do not start the clock. For a fuller explanation, see when a renovation needs a permit.

Hazardous materials add a layer of responsibility. Asbestos removal and lead paint removal are specialist trades. Paid electrical work is done by a Licensed Electrical Contractor with an ESA permit. Gas work is done by a TSSA-registered contractor. Plumbing changes need a plumbing permit and a licensed plumber. Structural changes need a design by a qualified designer or engineer and a building permit. The homeowner’s role is to hire the right people, keep the paperwork, and make sure the contract sets out who does what.

A comparison of the three main hazards helps with planning:

What goes wrong

The most common mistake is starting demolition before testing. Once a wall is open and debris is mixed, testing becomes harder and the cost of cleanup rises. Another mistake is assuming that a house built after 1990 is free of asbestos; it was used mainly before 1990, not only before it, so a newer house can still contain older materials reused or left from earlier work. A third mistake is treating vermiculite insulation as ordinary insulation and disturbing it. Do not disturb vermiculite insulation.

A fourth mistake is hiring a general contractor to remove asbestos or lead paint without checking that the crew is trained for that work. Removal is a specialist job. A fifth mistake is closing walls before the electrical assessment. Older wiring should be assessed by a Licensed Electrical Contractor before walls are closed, because rewiring after the fact means opening the walls again. A sixth mistake is leaving hazardous materials out of the contract and the schedule. If the contract does not say who handles testing and removal, the work can stall.

Finally, remember that rules differ between municipalities. Check with your municipality’s building department about permit requirements and inspection stages, and take legal questions about your contract to a lawyer. Whoever does the testing and removal, put it in the written contract.

Planning a basement or whole-home renovation

Older homes often have basements that were finished decades ago with materials that may contain asbestos or lead paint. Finishing a basement is a good moment to test and, if needed, install a radon mitigation system. For the full process, see finishing a basement in Ontario. A whole-home renovation or gut renovation will disturb more materials, so testing and scheduling become even more important. See whole-home renovation: planning a gut renovation.

In every case, the sequence is the same: find out what is there, test before demolition, hire qualified people, and build the results into the permit drawings and the schedule. That is how an older home renovation stays safe and predictable.