Crawlspace Mould Remediation - Residential Home, Transcona

Air testing inside the crawlspace showed spore counts in excess of 40,000 CFU/m3, with Aspergillus/Penicillium and Chaetomium as primary species. Moisture readings on affected joists ranged from 22% to 31% - well above the 19% threshold at which mould becomes established. The incorrect vapour barrier had been in place for an estimated 6-8 years.

A homeowner purchased a 1978 two-storey in Transcona and discovered extensive mould growth on the crawlspace floor joists during a pre-possession inspection. The previous owner had installed plastic vapour barrier incorrectly, trapping moisture against the wood. Nearly 400 sq ft of joists showed active mould growth and early wood rot.

Remove incorrect vapour barrier. Remediate all mould-affected joists (approximately 400 sq ft). Apply encapsulant to remaining structural members. Install correctly configured ground cover vapour barrier. Improve crawlspace ventilation per code. Post-remediation air clearance testing.

The crawlspace was isolated from the living space using poly barriers at all penetrations. Technicians in full PPE removed the existing vapour barrier and HEPA-vacuumed all surfaces before using a dry-ice blasting method on accessible joist surfaces to remove mould colonies without chemicals. Encapsulant was applied to all wood within the crawlspace. A new ground cover vapour barrier was installed with proper overlaps, taped seams, and perimeter attachment.

Post-remediation air testing inside the crawlspace returned below 500 CFU/m3 - within normal outdoor baseline ranges for the season. Moisture readings across all treated joists dropped to 14-16% within 30 days. The homeowner completed the purchase with confidence and the insurer accepted our clearance certificate.

Incorrect vapour barrier installation is one of the most common causes of crawlspace mould in Manitoba. We now include a vapour barrier audit in every crawlspace inspection, regardless of the presenting complaint.

Services Performed

• Crawlspace Inspection & Air Testing
• Mould Remediation (Dry-Ice Blasting)
• Wood Encapsulant Application
• Vapour Barrier Replacement
• Ventilation Assessment
• Post-Remediation Clearance Testing

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