Does dry ice blasting remove attic mould in Ottawa homes?

Dry ice blasting is a method some contractors offer for attic mould, but the method itself is not what determines whether the job is done properly. What matters is whether the moisture source is fixed, whether all visible mould is removed, and whether the written scope covers both.

Health Canada sizes mould by area. Small is one to three patches, each less than 1 square metre; medium is more than three patches, or patches greater than 1 square metre but less than 3 square metres; extensive is a patch larger than 3 square metres. Health Canada says you can generally clean small and medium areas yourself, and recommends professional help for extensive mould growth.

Any method that blasts, brushes or sands a surface disturbs what is on it. In an older Ottawa attic, the insulation (including any vermiculite) may contain asbestos: Health Canada lists insulation among older building materials that may contain it and says vermiculite-based insulation may contain asbestos, and Ontario's guide notes that asbestos was widely used in sprayed-on material and pipe and boiler insulation until 1973, with many other materials continuing into the mid-1980s. Before any work that cuts, scrapes or disturbs those surfaces, have the materials tested. If asbestos is found, the contractor assesses friability and the area to be disturbed on site, which determines the Type under O. Reg. 278/05, and what the contractor must do by law changes significantly depending on that Type. Do not disturb suspect material further before testing is done.

We found no Ontario rule that licenses or regulates mould remediation companies as such, and no industry mould guideline has the force of law. What a fair quote should include is a description of the method, the scope of surfaces to be treated, confirmation that the moisture source will be identified and addressed, and a post-remediation check confirming no visible mould remains. Ask whether the contractor will also inspect for the source of the moisture intrusion, because dry ice blasting or any other cleaning method applied without fixing the source will not prevent recurrence.

We found too few published Ottawa prices for mould remediation to quote a range, so compare written quotes on the same scope.

After the job is finished, keep the written contract and scope, any post-remediation report the contractor provides, and documentation confirming the moisture source was repaired. Keep them together. Contractors listed in the Ottawa Construction Network directory can be reached through the request form on this page and reply by email.