Mould Remediation in Westwood

Westwood was developed mainly in the 1960s on the west side of the city, a consistent neighbourhood of bungalows and split-levels on heavy clay. The original foundations are sound mid-century construction with full basements. Crawlspaces here are the later layer: rear additions, sunrooms, enclosed carports and converted porches added through the 1970s, 1980s and beyond.

These additions follow the same pattern we see across every postwar neighbourhood in Winnipeg. Support was set shallow — often sonotube piers well above the design frost depth — and the clay beneath them freezes to depth each winter and lifts them. Twenty or thirty cycles later, the addition is visibly out of level, the junction with the main house has opened, and the crawlspace underneath is pulling cold air in winter and humid air in summer. With batt insulation between the joists holding moisture against the subfloor, mould on the sheathing is the predictable outcome.

Clay shrinkage in dry summers compounds the water problem by opening a channel beside the foundation for the next heavy rain. Our work in Westwood is typically a combined structural and envelope job: bring support down to stable bearing below frost depth, correct grading and downspouts, add interior drainage only where groundwater actually warrants it, then encapsulate with a sealed barrier, insulate the perimeter, and confirm the space holds humidity through a full year.

Westwood calls are the standard 1960s pattern: a rear addition or enclosed carport on shallow piers, a floor that has gone out of level, doors that bind in deep winter, and a crawlspace underneath with batts in the joists and frost on the sheathing. Owners often mention they have had the tile repaired more than once.

Our first recommendation is to establish founding depth and correct support below the frost line, because repairing finishes above a moving structure is money spent twice. Grading and downspout work follows, then sealing and perimeter insulation. Interior drainage goes in only where readings show groundwater is genuinely active rather than by default.

Mould needs three things: an organic food source, moisture and moderate temperature. A Winnipeg crawlspace supplies the first in abundance — joists, subfloor sheathing, beams, paper-faced batt insulation — so control comes down to moisture. That is why every remediation we perform starts with finding the water. In this climate it is usually one of four sources: meltwater entering through foundation backfill in spring, groundwater rising through the floor, summer humidity condensing on cool surfaces in a vented space, or warm indoor air condensing on cold framing in winter.

The remediation itself follows a disciplined sequence. We establish containment so spores are not distributed into the living space, set up negative air with filtration where the situation calls for it, and work in appropriate protective equipment. Porous materials that cannot be cleaned — most importantly contaminated fibreglass or cellulose insulation, cardboard and stored soft goods — are bagged and removed. Framing is then cleaned mechanically. Surface growth on structural wood is typically abraded or HEPA-vacuumed and wiped rather than merely sprayed, because a coating applied over a living colony does not remove it.

We are careful about what we promise regarding treatments. Biocides and antimicrobial coatings have a place, but they are not a substitute for removing growth and fixing the moisture source. Any contractor telling you that fogging a crawlspace solves mould is selling a cosmetic result. Likewise, we do not diagnose health effects — that is a matter for your physician — but we will tell you plainly that air moves from a crawlspace into your living space through the stack effect, continuously, during the heating season, and that what is growing down there is part of what you breathe upstairs.

Structural assessment is part of the job. Prolonged moisture does more than grow mould; it degrades wood strength. We probe sill plates, post bases, beam ends and sheathing to identify where decay has gone past surface staining into section loss. In Manitoba we find this most often at the ends of sill plates on the north and east sides of a house, and under bathrooms and entries where interior leaks have added to the load. Where decay is structural rather than cosmetic, repair or sistering of members happens before the space is sealed.

Once the growth is removed and the framing is sound, the moisture correction determines whether the problem returns. That might be exterior grading and downspout work, interior drainage with a sump, a sealed vapour barrier over the soil, perimeter insulation to raise surface temperatures above the dew point, or dehumidification — frequently several of these together. We finish by documenting framing moisture content and relative humidity so you have numbers rather than impressions, and we recommend a follow-up reading after the first full seasonal cycle.

Scope and containment should be proportionate to what is actually there, and we will tell you which category you are in. A few square feet of surface growth on a joist bay near a past plumbing leak is a modest, contained job. Growth distributed across the subfloor of an entire crawlspace, with saturated insulation and elevated readings throughout, is a different undertaking requiring full containment, negative air with filtration, and staged removal. Contractors who apply maximum containment to every job inflate the price; contractors who apply none distribute spores through your house. Matching the method to the extent is part of the assessment.

There is an insurance and documentation dimension worth handling properly from the start. If the moisture source was a sudden event — a burst supply line, a failed water heater, a storm — your policy may respond, and insurers want specific material: photographs of the conditions, moisture readings with locations, the cause as far as it can be determined, and an itemized scope. We document all of that as a matter of course because it is how we work, but it also means you are not trying to reconstruct evidence after the fact. We will not tell you what your policy covers, and we would rather you call your broker early than rely on our guess.

After remediation, verification is the step people skip. The meaningful tests are whether framing moisture content is trending down toward the mid-teens, whether relative humidity in the sealed space is holding near 50 to 55 percent through a full summer, and whether the odour upstairs has gone — including when the furnace runs, which is when crawlspace air is most actively distributed. We take readings at completion and recommend one more at the end of the first summer. If the numbers have not moved, the moisture source was not fully corrected, and that is our problem to come back and solve rather than yours to live with.