Why Attic Mold Is So Common in Burnaby — And What to Do About It

If you've had a home inspection done in Burnaby or the surrounding Metro Vancouver area, there's a decent chance the inspector flagged something in the attic. Attic mold is one of the most common findings on home inspection reports in our region — and most homeowners have no idea it's there until that moment.

Why attics are such a problem in Metro Vancouver

The core issue is moisture. During the colder, wetter months — which in Burnaby means roughly October through April — warm, humid air from inside the house naturally migrates upward. When that air reaches the cold underside of your roof deck, it condenses. Do that repeatedly over a winter and you've got standing moisture on wood. Mold follows within days.

The problem gets worse when attic ventilation is poor. Soffit vents blocked by insulation, missing baffles, or undersized ridge venting all trap that humid air in the attic rather than letting it exhaust out. Bathroom fans or kitchen range hoods that vent directly into the attic — instead of through the roof — are another common culprit. We see it constantly.

What attic mold looks like

Early-stage attic mold typically shows up as dark speckled staining on the underside of the plywood roof sheathing. It looks a bit like someone scattered pepper across the wood. Left alone, those spots spread and merge until sections of the roof deck are covered in dark, fuzzy growth. Rusted nails are another sign — the oxidation tells you there's been chronic moisture in that space for an extended period.

You usually can't see any of this from inside the house. The attic hatch is often the only access point, and most homeowners never open it.

Does attic mold mean the roof is ruined?

Not necessarily. In most cases, attic mold is a surface issue on the sheathing and rafters — it can be cleaned and treated without replacing the structural wood. That said, if the moisture source isn't fixed at the same time, the mold will come back. Remediation without ventilation correction is a short-term fix.

In severe cases, where the sheathing has been wet for years and is starting to delaminate or rot, replacement becomes part of the scope. A proper inspection will tell you which situation you're in.

What the remediation process involves

A proper attic mold remediation job typically involves:

• Inspection with moisture readings throughout the attic
• Identifying and correcting the ventilation or moisture source issue
• HEPA vacuuming of loose spore debris
• Treatment of affected wood with an antimicrobial biocide
• Insulation management — moving, protecting, or replacing blown-in insulation as needed
• A clearance air test if required by a lender or buyer

When should you call someone?

If a home inspector flagged attic mold, don't wait. Buyers routinely require remediation as a condition of sale. Sellers who get ahead of it with a proper scope — rather than a last-minute quote chase — are usually in a better position to negotiate.

If you're not selling but noticed something on a routine inspection, the same logic applies: the longer it sits, the more it spreads and the bigger the scope gets. A smaller job caught early is always cheaper than a large one caught late.

Give us a call and we can usually tell you a lot from photos before anyone sets foot in the attic.