How Victoria is built
- Before 1961 59%
- 1961–1990 25%
- 1991–2000 6%
- 2001 or later 11%
Why mould shows up in Victoria homes
Victoria gets about 2,763 heating degree-days a year, a measure of how much heating its climate needs, and its winter design temperature, the cold day heating systems are sized for, is −1.3°C. Those figures come from the climate data for Victoria Gonzales in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. Mild, wet winters keep materials damp, so poorly vented bathrooms, basements and crawlspaces are the usual suspects.
Of Victoria's 14,695 houses (single-detached, semi-detached, row houses and duplexes), 59% were built before 1961 and 84% before 1991, according to the 2021 Census. Older basements without a moisture barrier and houses that were air-sealed without adding ventilation are common trouble spots.
Mould inspection: when sampling is worth it
Start by looking and smelling: stains, discoloured patches, peeling paint and a musty odour, especially in basements, bathrooms, window frames and closets on outside walls. Health Canada says measuring mould concentrations or identifying species is usually unnecessary.
No Canadian province has a mandatory mould standard for homes. Health Canada's guideline sets no numerical limit: it says to fix moisture problems and clean up visible mould.
Air or surface sampling helps in three cases:
- You smell mustiness but can't find the source.
- After a leak or flood, to check that cleanup worked.
- Before buying an older house with signs of past water damage.
Cleanup and remediation: the size rules
CMHC and Health Canada sort mould by size, and the size decides who should clean it up:
| Size | What counts | Who should clean it |
|---|---|---|
| Small | One to three patches, each smaller than 1 m² | A healthy homeowner, with water and unscented dish detergent (CMHC) |
| Medium | More than three patches, or patches between 1 and 3 m² (32 square feet) | Trained help; homeowners only with training and precautions |
| Large | A patch larger than 3 m², or many patches through the house | A qualified mould remediation contractor (CMHC) |
- Fix the moisture source first: a leak, poor drainage, or condensation from high humidity. Health Canada recommends 30–50% relative humidity.
- For a small cleanup, wear safety glasses or goggles, an N95 mask if possible and household rubber gloves. People at risk from mould shouldn't clean it and should stay away.
- Health Canada suggests professional help for extensive mould, especially growth that keeps coming back after cleaning.
Choosing a tester, lab or remediation contractor
Ask any Victoria tester which lab analyzes their samples, and look for one accredited under AIHA's EMLAP program for environmental microbiology. Pair sampling with a ventilation and humidity assessment, which finds the cause. For remediation, get two or three written quotes that describe containment, what will be removed and how the area is cleaned.
Ventilation and humidity assessments in Victoria · Our mould and indoor air quality guide
Coastal BC Lower Mainland and Vancouver Island
What this means in Victoria’s climate
Mild, wet winters and summer heat waves: fix moisture first, then cooling and heat pumps.
Coastal BC has Canada's mildest winters, but heavy rain from fall to spring soaks walls and roofs, and summer heat waves are now a health risk. Heating needs are the lowest of any region we cover, so damp, drafts and overheating are the common complaints. An EnerGuide evaluation here should look for moisture problems before any air sealing or insulation, then plan a heat pump that heats and cools.
- Fix moisture before tightening up. Heavy winter rain soaks walls and roofs here. Insulation makes outer layers colder and slower to dry, so fix leaks, condensation and mould first, or upgrades can trap water. Ask: Ask the registered energy advisor to note stains, damp spots and roof or window leaks, and to check that bath and kitchen fans vent outdoors.
What else homes in Victoria need →
Sources for this climate guide · checked October 26, 2026
- National Building Code of Canada 2020, climate data (NRC)
- Canadian Climate Normals 1991–2020 (ECCC)
- Keeping the Heat In (NRCan)
- Air-Source Heat Pump Sizing and Selection Guide (NRCan)
- Heat pump basics (NRCan)
- Heating and Cooling With a Heat Pump (NRCan)
- Primary heating systems by household, Table 38-10-0286-01 (Statistics Canada)
- Electricity price comparison, April 2025 (Hydro-Québec)
- BC Coroners Service review of 2021 heat deaths
- Wildfire smoke, filtration and cooling (Island Health)
- Wildfire smoke: protecting your health (Government of Canada)
- Canada's top weather stories of 2020 (ECCC)
- Canada's most impactful weather stories of 2024 (ECCC)
- 2024 Cross-Canada Survey of Radon Exposure
- Guide for Radon Measurements in Homes (Health Canada)
- Conditions for thermal scans, ASTM C1060 summary (Cx Associates)
Mould and indoor air quality testing in Victoria: common questions
How much does mould testing cost in Victoria?
We found no reputable Canadian source for the cost of a professional mould assessment, so get two or three written quotes and ask how many samples are included, which lab analyzes them and what the report covers.
Do I need a test if I can see mould?
Usually not. Visible mould needs cleanup and a fix for the moisture source. Testing helps most when you suspect mould you can't see.
How much mould can I clean myself?
CMHC says a healthy homeowner can clean one to three patches, each under 1 m², with water and unscented dish detergent. Larger areas need trained help or a remediation contractor.
When should I hire a mould remediation contractor?
For a single patch over 3 m², many patches through the house, or mould that keeps coming back after cleaning (CMHC, Health Canada).
Is there a legal mould limit for homes in Canada?
No. Health Canada sets no numerical limit; its guidance is to control moisture and clean up mould. Quebec has a voluntary handling standard.