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Personal: Residential

Frame and Sash Materials for Windows and Skylights

A window consists of a glazed unit, a frame and a sash. The glazed unit fits into the sash, and the frame holds the sash. Frames and sashes are manufactured from a variety of materials and combinations of these materials. Good quality windows and skylights can be made of a variety of materials, each with different characteristics:

  • Aluminum is strong and durable, requires little maintenance and resists warping. However, aluminum frames and sashes must be designed with significant thermal breaks to reduce heat loss by conduction.
  • Fibreglass offers excellent thermal performance, is durable and requires minimal maintenance. Hollow sections of the frame and sash may be filled with foam insulation to further reduce heat loss.
  • Vinyl provides good thermal performance and is easy to maintain. Large units may need reinforcement to increase their strength, and some reinforcing materials can increase conductive heat loss. Hollow sections of vinyl frames can be filled with foam insulation.
  • Solid wood has good insulating value and structural strength but requires protection from the weather, either through regular painting or staining or the use of low-maintenance, factory-applied claddings and finishes.
  • Combination frames and sashes are constructed of two or more materials, to take advantage of the best features of each material.
  • Composite frames and sashes are constructed of materials that have been blended so that the virtues of two or more materials are present in a single product.

Windows, doors and skylights can be compared by their energy performance and airtightness.