Update on Risks and Control of Mould,
Lead and Silica on Construction Projects

- - Part 3 - -

Canadian Construction Association:

Mould Guidelines for the Canadian Construction Industry, 2004

The Canadian Construction Association represents the interests of the non-residential construction sector in Canada. It published, “Mould Guidelines for the Canadian Construction Association”⁷ , in early 2004, with the intent of providing stakeholders (designers, constructors and building owners) with information to assist in reducing the risk of mould growth on construction projects. The Guide was written by a national committee comprised of general contractors, architects, insurance professionals, environmental consultants, lawyers, and hazardous materials abatement contractors. A guiding principle of the document is that designers, constructors and building owners have a shared responsibility to reduce mould growth on projects and in building operations.

The Guide begins with a discussion of legal, insurance and health effects issues. Considering the US experience, it is likely that mould will become a legal issue in Canada and will result in claims by owners and occupants against those involved in the construction process.

Mould is recognized as a public health issue by federal and provincial regulators, both for occupational health and safety and public health. Generally, the insurance industry’s position is that mould is not covered under commercial insurance policies. Endorsements specifically excluding mould have been added to most coverage in the past few years. It is important that contractors check their insurance coverage and that of their subcontractors.

The Guide acknowledges that mould growth in buildings is a risk factor for adverse health effects in occupants. Certain occupants (infants, elderly, individuals with respiratory conditions, etc.) may be more susceptible to mould exposure. People with specific health concerns should consult with their doctor if concerned about mould exposure.

Perhaps the major contribution of the CCA Guide 82 to the professional advice on mould control is the set of recommendations offered to prevent mould growth in buildings.

• Designers can substitute newer mould-resistant materials for materials and finishes that have suffered mould growth in traditional designs. For example, fiberglass mat drywall products are now available to replace cellulose paper based drywall products.
• Designers should employ proper rain-screen design principles to permit the escape of rainwater that may penetrate the exterior cladding.
• Designers should also recommend mock-ups be built of critical assemblies subject to water infiltration so that the designer, builder and trades can identify problems that might lead to excessive leakage.
• Ventilation engineers also have a responsibility to design systems so as to minimize mould or microbial contamination.
• The builder is responsible to ensure that the construction process does not allow mould growth.
• Mouldy materials should be rejected.
• Susceptible materials should be handled and stored to as to avoid moisture.
• Standing water should be eliminated in buildings as quickly as possible. Susceptible finishes should not be installed next to wet or drying materials until they have reached an acceptable level of retained moisture.
• All susceptible materials must be dried within 24-48 hours of any wetting, accidental or intentional.
• Susceptible materials should not be installed until the interior environment can be controlled to prevent mould growth.
• Mouldy materials must not be installed.

Implementation of these precautions will require training of supervisors and workers.

Mould growth may already exist in a renovation of a building. The contractor is advised to perform a careful check for indications of mould growth prior to entering into a contract for a renovation. The Guide gives a detailed inspection checklist to help the contractor identify potential mould growth. The Guide also discusses the possible need for intrusive inspection, and sampling and analysis, to fully document the extent of mould growth.

Guide 82 gives detailed precautions for remediation of mould growth. Mould growth is classified by extent of affected material into:

• Level I (less than 10 square feet of mould affected material),
• Level II (10-100 ft2)
• Level III (greater than 100 ft2) ,
• Small Scale contamination within ventilation units (under 30 ft2)
• Large Scale within ventilation units (30 ft2 or greater).

These precautions are very similar to the EACO work practices discussed in Section 1.4 .

The CCA Guide discusses mould controls during decommissioning and demolition work. Where workers will enter mouldy buildings to disconnect services, prepare the structure for demolition or to salvage items or finishes, personal protective and hygiene practices similar to Level III mould remediation must be followed. Expert advice should be sought regarding the need to remove mouldy materials prior to demolition. The proximity to other buildings and the susceptibility of their occupants should be among the factors considered.

The Canadian Construction Association intends to continually update this Guide, as further information is available. It will also offer seminars and information packages to construction audiences across the country.

PEN # 19 "Update on Risks and Control of Mould,
Lead and Silica on Construction Projects"

continues with

PEN #19 "Update on Risks and Control of Mould, Lead and Silica on Construction Projects"

Bruce Stewart CIH, ROH
Senior Vice President
Pinchin Environmental Ltd.

Presented at Construction Superconference
Toronto, November 29, 2004

⁷ Canadian Construction Association; Mould Guidelines for the Canadian Construction Industry; CCA; Ottawa, ON; 2004 (http://www.cca-acc.com/documents/electronic/cca82/cca82.pdf).

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