An Older Technology Given New Respect

By Al Dueck

Reproduced by Permission of Canadian Property Management

Todays market demand products that are low maintenance, provide appealing aesthetics and high performance at reasonable cost. Building occupants, managers and owners have a great deal of choice and have become extremely demanding. These demands have not always been satisfied with the building materials available or in popular use. Consequently, it has become a growing issue to find the best possible replacement products for a range of buildings. Windows are one such product.

Even today, buildings continue to be constructed that will be energy hogs, losing excessive heat through air leakage or conductivity, and maintenance nightmares, with peeling or fading paint, failing frame and/or insulating components. This is due to a lack of awareness or simply short-term thinking.

Credible fenestration suppliers are generally able to provide independent test results of performance characteristics - air and water infiltration, structural properties, as well as security and ease of operation considerations. Test reports using CSA standards can be reliable indicators of the designed performance capabilities of the window products. Furthermore, the track record of manufacturers and distributors should be considered when looking at any product.

The choices in window and door frame/sash materials include wood, aluminum, vinyl and pultruded fiberglass materials. Each of these materials its own unique properties to be considered.

Wood, generally pine or fir, has been used for many years in windows due its aesthetic quality. However, it has become more expensive as raw materials have become a precious commodity. Maintenance requirements have also become a deciding factor.

Aluminum has been recognized for its durability. However, the high conductivity of aluminum raises concerns of condensation and lower window U-values. This results in low energy efficiency.

Vinyl has been a very popular material in residential construction, both for window retrofits and new building. Lesser strength characteristics and limited colour flexibility have raised doubts that it can be used for architectural and commercial applications.

Pultruded fiberglass has been used extensively in complicated applications for the past 30 to 40 years (i.e. bridges and boats). It has characteristics that are superb for fenestration applications - low conductivity, excellent strength and very low rates of expansion and contraction.

Pultrusion 101

Pultruded fiberglass window lineals, the base for window sash and frame construction, are created by pulling glass roving and matting (high quality products should have 60% plus glass content) through thermoset resins, a forming station and finally a sophisticated dye. This process creates an extremely tough material so tough it must be cut with diamond bit saws in the fabrication process. The pultrusion process results in lineal components that have excellent strength and, not surprisingly, similar expansion and contraction characteristics to glass, a very stable material. Important progress has been made by a handful of companies specializing in this field. These companies have mastered the art of creating "thin wall pultrusions," which demonstrate high performance levels and are cost effective for fenestration applications.

Low maintenance

Building managers/owners should consider the long-term performance characteristics of the material they choose. Wood, even with high quality paint finishes, requires refinishing in an unacceptably short time for commercial applications. Vinyl is reputed to have a long life but has not yet won the confidence of many commercial applications. Aluminum has developed a range of paint options that may deliver superior long-term performance. Fiberglass, meanwhile, has a superb substrate for high quality paints on interior as well as exterior applications.

Durability/life expectancy

Well-maintained wood windows have proven durability, if they are properly looked after. Non-thermally broken aluminum windows have proven durable. Thermally broken aluminum is a relatively new product and has yet to prove itself. Pultruded fiberglass has been in use for several decades and requires little maintenance.

Pultruded fiberglass products are also non-corrosive. Mike Mrakalj of D& M Windows, manufacturers of fiberglass windows, notes a retrofit they did for the Windsor Salt company. "The company had installed vinyl windows and they failed in less than 2 years in this highly corrosive environment. They replaced them with fiberglass several years ago and we have not heard from them since."

Energy efficiency

Progress has been made in several ways in the construction industry to reduce energy consumption. Effective and durable weather stripping materials ensure that a weather-tight seal is created from date of installation through useful lifetime. A stable (low thermal expansion) material such as pultruded fiberglass used in windows should result in more consistent weather seals in all weather conditions from extreme heat to extreme cold.

Government agencies in both Canada and the U.S. have specifically recognized that pultruded fiberglass is the highest performance window material available today.

Environmental considerations

Pultruded fiberglass is recognized as an optimal product with "green building" concepts such as the CMHC Healthy House in Ontario. "Pultruded fiberglass is seen to be one of the lowest impact materials available, provides excellent thermal performance and has the lowest embodied energy of any material I am familiar with," says Martin Liefhebber . "We found the material to be very flexible to meet our design needs in product type, size and color."

Window types

Today, fiberglass windows are available with up-scale options such as simulated divided lines, remodeled brickmoulds and even laminated wood to the interior. This creates exceptional opportunities where the combination of custom sizes and wood interior creates opportunities for beautiful remodeled windows. "Vinyl or aluminum windows can not provide some of the capabilities of pultruded fiberglass. We are finding that consumers and architects are increasingly receptive to something other than vinyl," explains Phil Warnell, Sales Manager for Window & Door Store in Toronto.

Finish choices

A long-term commitment to a durable pre-finish may also require careful consideration of the frame/sash finish to the exterior as well as the interior. Review the colour alternatives for inside and outside - split finish, as in one color outside, one color inside, may also be available at a reasonable cost. Interesting detailing can also be achieved through combinations of having the brick mould and frame in different colors.

A Case Study Bayview Condominium

Bayview Condominium in Leamington, Ontario, was built in 1989. Although relatively new, it had encountered difficulties with windows extremely large patio doors and the building envelope. In theory, the enclosure system was supposed to ensure air- and watertight security. In practice, the outer doors frosted up in winter, and the aluminum frames despite built-in thermal barriers conducted the cold right into the rooms.

Joe Passo, Architect, was retained to research the market and recommend ways to solve the problem. The choice of replacement windows and doors focused on high performance glass and pultruded fiberglass frames. In the following winters there were no drafts, no icing up or frost to mar the view, and despite a 30 per cent colder winter following the retrofit, fuel bills did not increase.

Historical considerations

Replacement of windows in historic buildings has come under increasingly careful scrutiny. Notably, pultruded fiberglass windows have met the requirements with ingenuity and excellent application of technology. Matching of historical colors and/or the use of split finish capabilities and unique fixed, magnum double hung configurations have resulted in approved window replacements. Notable projects include the historic Bessborough Hotel in Saskatoon.

The Delta Bessborough, located on the banks of the South Saskatchewan River, was in need of a substantial retrofit, including changes in the heating system and replacement of very drafty windows. The management team was concerned about retaining the historic look of the building. However, they also wanted windows that were easy to clean and allowed access to fresh air. The choice of double hung tilt windows met all of these needs, and allowed the custom matching of the required green exterior.

"We replaced about 225 windows, and the installations went very smoothly, with minimal interference in the rooms a key consideration for our operation," says Debbie Kobelsky, Rooms Division Manager. "The new, air-tight windows have been one of the most appreciated changes by the hotel guests. It drops to minus 40 here, and this winter our complaints about drafty windows dropped to zero."