Tips Before Installing a Box Sash Window

Box sash windows often are found in older homes.

Traditionally found in Victorian and Georgian-styled homes, a box sash window opens and closes through the counterbalancing of a weight-and-pulley system. It has two sashes or frames, one usually above the other, so that one can slide over the other to use the window. This is a complicated do-it-yourself project that requires specific tools, including a twin-bladed sash chisel. Accurate construction also is required for the frame and sash or the window will not work properly.

Things You'll Need

• Redwood, pine or oak wood, treated with fungicide and insecticide
• Twin-bladed sash chisel
• Weight-and-pulley system
• Panes of glass
• Measuring tape

Instructions

1. Obtain a plan for building the window before starting. A source often cited by do-it-yourselfers is the four-volume "Audels Carpenters & Builders Guide," available through online booksellers and classified ads. While construction of the sash frame with a few joints is fairly easy, creating the cutout pocket for the pulley is more complicated. A series of transverse and longitudinal cuts must be made using the twin-bladed sash chisel. The pulley block also must not be farther than 3 inches from the top, for example, or there will not be sufficient height for the weight.

2. Consider the window's design options, especially if you are building a replacement for a heritage home. Shannon Kyles, who teaches History of Western Architecture at Mohawk College in Ontario, Canada, has gathered together a gallery of traditional box sash window types common to certain eras and displays them online. For example, the classic Georgian window had six panes of glass in each section, with a final sum of four glass panes down and three across. A hung sash window, on the other hand, is more common in the United States and means the window has two sashes that move up or down in a window frame.

3. Incorporate modern materials if possible into your box sash window project. Old wooden box sash windows might be suffering from rot and wood distortion. Synthetic materials are more common now to avoid these problems, but they often cannot be used in heritage restoration projects.

References

• Shannon Kyles's gallery of styles
• Sash Windows Australia
• Everything you need to know about box sash windows - video

Resources

• Understanding window terminology