March 21, 2005
Benefits of masonry touted in study
Experts say controlling moisture is the best way to prevent mould
Water intrusion into walls can cause serious mould and structural damage.
One of the keys to preventing mould is controlling moisture.
According to Bill McEwen, executive director of the Masonry Institute of B.C., brick rainscreen wall systems have a long-standing tradition for moisture resistance.
“If a system has a better moisture management, then there’s less mould concern and masonry rainscreens have been well proven for that,” he said. “Masonry doesn’t encourage mould growth by not being a food source but if it does occur, at least masonry can be easily cleaned and there’s no damage in the cleaning process.”
Brick wall systems provide three levels of moisture protection: the brick veneer; an air space cavity; and the sheathing membrane.
“Masonry can also protect other materials in a wall system that would be more susceptible to mould through its rainscreen and durability,” noted McEwen, adding the advantages of masonry are well understood by the industry.
A study by Masonry Canada on fungal mould resistance conducted in 2003 confirmed clay brick and concrete block did not support mould growth whereas substrates made of wood and paper products produced measurable amounts.
“If you handle that moisture incident quickly within 24-48 hours to get it dry, then you won’t have a mould issue.”
Building with better materials that are more forgiving of moisture penetration is one measure of prevention.
Implementing proactive moisture management programs are another in responding to the challenges of mould and fungi growth.
Four speakers at the recent B.C. Construction Show in Vancouver provided insight to proactive solutions and tools for IAQ mould and moisture control in a session called Innovative Approaches to Indoor Air Quality Mould and Moisture Management.
In his presentation, Michael Glassco, operations manager at Theodor Sterling Associates, gave an overview of the importance and benefits of a proactive IAQ program.
Instead of a “reactive” IAQ investigation of an existing mould problem, Glassco recommended proactive testing.
This entails regular testing of IAQ every six months to a year to prevent a problem from escalating into a real concern.
Among the reasons for implementing a proactive IAQ program are to meet regulatory requirements.
“In B.C. we have some pretty strict regulations on IAQ — perhaps the most strict in Canada,” advised Glassco. “Implementing such a program can help address these issues.”
Proactive moisture and mould management requires inspections, procedures, or policies to minimize the likelihood of moisture infiltration into buildings as well as expeditious handling of a moisture incident.
“If you handle that moisture incident quickly within 24-48 hours to get it dry, then you won’t have a mould issue,” he said, emphasizing the importance of scheduled regular inspections.
Glassco also noted that B.C. is the only place he is aware of in North America where regulations exist for assessing and remediating mould issues.
“In B.C. we’re regulated by WCB. They have a guideline Regulation 4.79 that talks about how to investigate an IAQ issue,” he said. “They say assess a mould issue visually, look behind baseboards, correct that water source.”
One way to stop mould problems before they start is through the use of mould resistant coatings (MRC).
“MRC is an applied product which provides a surface that is resistant to microbial growth,” explained Harry Certain, business development manager at Foster Products.
The anti-microbial technology is available in two different types of MRC: surface sprays and reactive coating.
Certain noted the product has been used effectively in mould remediation and commercial projects such as schools and food processing facilities. It has been used successfully in HVAC systems for 12 years, he said.
Over the last two years, builders and owners have started using the product in pre-construction on residential and multi-family housing.
“MRC can protect the building during the construction phase,” said Certain.
“The best use for it is protecting high-risk areas for the long term.”
MRC is not “a cure all” though, he added, citing the product is not a way to stop window leaks and it’s not a solution to poor building practices.
“These are great tools for people to use in situations where there is high humidity or suspected potential problems,” he said.
Other IAQ tools highlighted during the session included moisture and IAQ sensor technologies and an automated online IAQ reporting system.
The use of moisture detection sensors or moisture detention tape can help with detecting and locating water problems before any significant damage occurs, according to Gamal Mustapha of Detec Systems.
“Typically you place this tape in areas susceptible to moisture such as a window assembly or exterior wall,” he said.
Data from different moisture sensors can be collected and analyzed through a building health management system.
The IAQ software system can help with that data collection and analysis, said Peter Ciccone of IAQ Software Inc. It simplifies IAQ testing by recording measurements, compiling the data for analysis and generating a report.
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