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Features Codes and standards
Replacement Windows

The new code aims for a harmonized standard.

July 1, 2010  By Mike Davey

There’s no question replacement windows are a big market. In fact, it
may be equal to or even greater than the market for new housing. It’s
certainly more stable.

There’s no question replacement windows are a big market. In fact, it may be equal to or even greater than the market for new housing. It’s certainly more stable.
As a class of products, windows and related fenestration technology has continued to improve in almost every area. However, these improvements don’t mean much when the window isn’t properly installed. Although hard numbers can be difficult to come by, some estimates state that more than 50 per cent of replacement windows aren’t being properly installed. There may be many reasons for this, including a lack of sufficient training on the part of the installer.
Dave Mitten is involved with the Siding and Window Dealers Association of Canada (SAWDAC), and recently spoke to Glass Canada regarding the association’s Window Wise program. Window Wise independently audits and certifies contractors and window manufacturers, and conducts comprehensive window installation training seminars for installers. Although the program has definitely met with some success, Mitten notes that SAWDAC had anticipated a much more comprehensive response from the installation community.
“We anticipated that it would be bigger than it is,” says Mitten. “Last year, the number of houses where the windows were replaced under Window Wise was just shy of 9,000. Those jobs were performed by about 45 contractors. Of those 45 Window Wise qualified contractors, three are in British Columbia, three are in Alberta, three are in Atlantic Canada, and the rest are in Ontario.”

There are certainly more than 45 companies installing windows in Canada. Note that a few provinces, such as Saskatchewan, Quebec and Manitoba have no installers certified under Window Wise at all.
“I believe there are only two reasons for an installer not to participate in Window Wise,” says Mitten. “Either they don’t meet the criteria, or they don’t understand the marketing value of it.”

Although proper installation is absolutely vital to ensure that a window performs as expected, there will soon be new standards to be followed for the windows themselves. According to the National Research Council (NRC), a new, harmonized performance standard for windows, doors and skylights has been developed and will be referenced in the 2010 National Building Code of Canada (NBC).
The new harmonized standard replaces a number of Canadian standards, some of which were outdated. The standard is AAMA/WDMA/CSA 101/I.S.2/A440, NAFS – North American Fenestration Standard/Specification for Windows, Doors, and Skylights.


A Canadian Commission on Building and Fire Codes task group recommended revisions to the National Building Code (NBC). The proposed changes went to public review in 2008 and have since been approved by the Commission.

As regards windows, the most important parts of the NBC are of course Parts 5 (Environmental Separation) and 9 (Housing and Small Buildings). Part 5 of the 2010 NBC will contain a new subsection, designed to ensure consistent application of the requirements and compliance procedures. Part 3 will include some vital changes as well, dealing with protecting against falls from residential windows.
In Part 9, a new section on windows, doors and skylights will replace the current sections that deal with doors and windows. Requirements have been updated to reflect the new, harmonized standard. In addition, performance requirements have been added, including some requirements regarding minimum targets for thermal performance.
The upshot of this is that builders, engineers and consultants will need to learn a new procedure for fenestration and entryway specifications. The 2000 edition of CSA A440 uses the well-known A (Air Leakage), B (Resistance to Wind Driven Rain) and C (Wind Resistance) system, but it is being replaced with actual design load and pressure ratings.
In addition, performance grades will need to be selected according to the CSA’s Canadian Supplement (CSA A440S1, Canadian Supplement to AAMA/WDMA/CSA 101/I.S.2/A440, NAFS – North American Fenestration Standard/Specification for Windows, Doors, and Skylights). This is also referenced in the 2010 NBC. The idea is to ensure that all fenestration products used are appropriate for the conditions and geographic location in which they are installed. Although windows, doors, and skylights will still be rated, the new harmonized standards present a tighter, more continuous standard to judge performance, rather than slotting every product into pre-assigned categories.
However, updated standards aren’t going to be much help if the windows are not properly installed to begin with. For example, nailing flanges are very popular in new housing. They may make life a bit easier, but there is a real risk of improper installation.
“There’s an incentive to not shim and fasten the windows on the sides, but just sort of hang it,” says Mitten. “Obviously, that’s against the CSA rules, but it still happens a lot. There’s also a bit of controversy surrounding the use of low expanding polyurethane foam. Once it’s formed a bond between the window and the frame, there may be a tendency for the installer to say ‘I don’t need to shim or fasten! The foam is doing the job!’ That may be true, but it’s not an approved method.”

The next edition of the National Building Code of Canada is expected to be released in November of 2010. For more information on upcoming changes to the 2010 National Building Code of Canada, please visit

For more information on Window Wise, please visit .

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