Renovate & Build Right. Stop Mould Before It Starts
The best defence against mould begins before walls are finished or floors are installed. According to Basement Builders, Canada’s leader in basement development with thousands of completed projects, most long-term moisture problems originate where concrete meets wood; at the foundation and sill plate connection.
To prevent mould from forming in this hidden space, they use TEKSILL, a Canadian-engineered sill plate protection that allows airflow and prevents water from being trapped at the base of walls.
This simple yet powerful barrier helps stop one of the most common causes of hidden mould in basements and lower-level structures.
Build Smart — Quality Construction Prevents Contamination
As Mike Holmes reminds homeowners, mould prevention starts with construction quality, not cleanup. Poorly sealed joints, improper vapour barriers, and rushed finishing work trap moisture inside the structure — allowing mould to grow undetected.
Smart building practices include:
- Installing vapour barriers and moisture-resistant drywall in high-humidity zones.
- Using pressure-treated lumber in areas that touch concrete.
- Sealing plumbing penetrations to prevent condensation inside walls.
- Allowing sufficient drying time for materials during construction or renovation.
When a space is built right from the beginning, it’s less likely to ever face mould contamination — no matter how old the home becomes.
(Source: Mike Holmes Website – Make It Right)
Maintain and Monitor — Everyday Moisture Control
Mould prevention doesn’t end after construction — it depends on ongoing vigilance. Health Canada recommends controlling indoor humidity between 30% and 50% to keep moisture in check.
Everyday steps to reduce humidity:
- Run bathroom and kitchen exhaust fans during and after use.
- Keep furniture slightly away from basement walls to allow airflow.
- Check for condensation on windows or cold surfaces during winter.
- Use dehumidifiers in damp spaces and empty them regularly.
- Clean and maintain air vents to ensure proper circulation.
Even small daily actions — like opening a window after a shower — play a role in preventing mould from taking root.
Dry Deeply — Don’t Stop at the Surface
After a leak or spill, the visible surface isn’t the full story. According to Basement Builders, one of the biggest mistakes homeowners make is not drying deeply enough after water damage.
Moisture often remains trapped behind drywall or under flooring, allowing mould to develop days or weeks later.
After any water event:
- Remove all standing water quickly.
- Use fans and dehumidifiers for several days — not just hours.
- Pull baseboards or flooring if needed to allow airflow.
- Inspect drywall and insulation for dampness before closing walls.
“Water that you can’t see is often the most dangerous.”
— Basement Builders Canada
Inspect Regularly — Small Checks Prevent Big Problems
The Canada Mortgage and Housing Corporation (CMHC) encourages homeowners to treat inspection as a habit, not an afterthought. Routine checks can prevent minor moisture issues from turning into expensive structural repairs.
Inspect:
- Under sinks, around tubs, and behind toilets.
- Near window frames, doorways, and vents.
- Basement corners and wall-floor connections.
- Behind stored items in cool, dark spaces.
The earlier a leak, stain, or musty smell is found, the easier it is to correct — and the less chance mould has to spread.