Question 1

Does my Thornhill home have lead paint?

Accepted Answer

If your Thornhill home was built before 1978, there is a high probability that lead-based paint is present on some surfaces. Interior trim, window sills and frames, doors and door frames, and stair railings are the highest-risk locations, as these surfaces received the most paint coats over decades and are also friction surfaces where paint deteriorates. Exterior siding and trim on pre-1978 homes also commonly contain lead paint. Homes built between 1978 and 1990 may still contain lead on exterior surfaces, as use phased out gradually. There is no reliable way to identify lead paint visually — XRF screening or chip sampling with lab analysis is required.

Question 2

Is lead paint dangerous if it's intact?

Accepted Answer

Intact lead paint in good condition — well-adhered, unpainted-over, and undisturbed — poses minimal ongoing risk in a Thornhill home. The hazard arises in two scenarios: deteriorating paint that chips, flakes, or chalks, which creates ingestion risk for young children; and disturbance during renovation — sanding, cutting, scraping, or demolishing lead-painted surfaces generates fine lead dust particles that are easily inhaled and cause irreversible neurological damage, particularly in children under six and pregnant women. Even brief renovation exposures without proper containment can generate lead dust concentrations many times above occupational exposure limits. Testing before any renovation work is the essential first step.

Question 3

Is lead paint testing required before renovation?

Accepted Answer

For commercial and institutional properties in Thornhill, lead paint testing and disclosure to workers before renovation is required under Ontario's OHSA and the Construction Regulation. For residential properties, there is no homeowner-specific legal mandate — but under OHSA, any contractor working on a pre-1978 Thornhill home has occupational health obligations to assess and control lead dust exposure. Most professional renovation contractors in Thornhill will require prior testing before sanding or demolishing painted surfaces in older homes. Failing to disclose known or suspected lead paint to workers also creates personal liability for property owners. Testing is the responsible and protective step.

Question 4

What is XRF testing?

Accepted Answer

X-ray fluorescence (XRF) is a non-destructive lead detection method that measures the characteristic X-ray emission from lead atoms in paint when exposed to an X-ray source. The XRF instrument is held against the painted surface and provides an immediate reading in milligrams per square centimetre (mg/cm²) without removing any paint or creating dust. XRF screening is the fastest and least invasive method for surveying a Thornhill home with many painted surfaces. Where XRF results are inconclusive or a regulatory-grade confirmation is required, small paint chip samples are collected and submitted to an accredited lab for confirmatory analysis. Our report documents every surface tested, its XRF reading, and its risk classification.

Lead Paint Testing Thornhill | XRF Certified | ASADS