Mould prevention for strata buildings

Sustained moisture on a surface that stays damp long enough for growth to take hold. In strata buildings the recurring suppliers are chronic condensation on cold surfaces, envelope leaks that wet assemblies from outside, failed ventilation that traps indoor moisture, and dead-air zones where damp never dries. The organisms are always present in ordinary air; the building conditions decide whether they get a foothold. Remove the sustained damp and the foothold goes with it.

Because cleaning removes growth without touching the moisture that fed it. A wiped-down closet corner that still sits below the dew point every cold night will be damp again within the week and stained again within the season. Recurrence is diagnostic: it says the surface has a standing moisture supply, either condensation on a cold spot or water arriving through the envelope, and that supply is what actually needs fixing.

The pattern usually answers it. One suite with damp in an otherwise dry building points toward that suite's moisture load and ventilation habits, which sit with the resident. The same stain repeating in the same location across a stack of suites points at a shared building condition, a cold slab edge or a failed exhaust riser, which is the corporation's. Councils should read the building-wide pattern before assigning responsibility to anyone.

Find the moisture source before arranging any cleanup, because growth without a diagnosed source will return. That means the standard reads: does the damp track rain or cold weather, is the surface a known cold spot, do the fans in that suite actually move air, and are other suites reporting the same location. Document with dated photos. Remediation of established growth belongs with qualified professionals, and so does the envelope investigation if the source points outside.

No. Paint hides the record and changes none of the conditions, and growth resumes behind or through the new coating because the surface is still damp on schedule. So-called anti-mould paints resist surface growth on their own film but do nothing about moisture arriving from a cold surface or a leak. Repainting is the last step, after the moisture source is fixed and the surface has been properly cleaned or replaced.

The cold and the still places: closet corners on exterior walls, the walls behind wardrobes in perimeter bedrooms, window sills and frames on north elevations, bathroom ceilings around underperforming fans, crawlspaces and storage rooms, and any suite directly above an open or unheated parkade level. Add the rain-fed suspects: walls below roof junctions, around window perimeters, and at cladding penetrations. A walk-through checklist covering those spots catches most problems early.

No, and that assumption misdirects a lot of strata spending. Condensation on a cold surface produces staining identical to leak staining, and it is the more common cause on the winter reports we assess. The separation comes from correlation: leak-fed damp tracks rain events on the exposed elevation, condensation-fed damp tracks cold weather and occupancy. Getting that call right decides whether the fix is envelope repair or thermal and ventilation work.

Significant or recurring growth belongs with qualified remediation professionals, who work to containment and removal protocols a building manager should not improvise. Anyone with health concerns related to mould should speak with a qualified health professional; that conversation is outside a contractor's lane and outside this guide. Where our work fits is the building side: finding and fixing the moisture source so that remediation, once done, stays done.

No, and councils should be wary of anyone promising it. The organisms travel in ordinary air and the materials in every building can host growth if kept damp. The achievable goal is a building that makes a poor host: surfaces warm enough to stay dry most nights, ventilation that exports each day's moisture, an envelope that keeps rain out, and habits that avoid parking humidity in dead corners. Those conditions can reduce the risk substantially.

It shortens how long surfaces stay damp, and drying time is the whole game. Working exhaust removes moisture at the source before it migrates to cold corners, and general air movement keeps surface humidity closer to room humidity, so overnight condensation dries by mid-morning instead of lingering into the afternoon. A suite whose surfaces dry fast is a poor host even when occasional condensation happens, which it will in any occupied Vancouver suite in January.

A deliberate look each fall, before the condensation season starts, catches failed fans, blocked ducts, and vulnerable corners while there is time to fix them cheaply. Pair it with the building's existing rhythms: annual fire inspections that enter every suite, depreciation report updates on the five-year cycle BC requires, and envelope maintenance walk-downs. The point is having eyes on the cold and still places on a schedule rather than waiting for complaints in February.