How to Measure the Rough Opening for Replacement Windows

Before replacing the windows in your home or office, you must get an accurate measurement of the window opening. An accurate measurement will ensure a proper fit, which makes the window easier to install and more energy-efficient.

Things You'll Need

• Tape measure

Instructions

1. Leave your current window in place if it isn't damaged. If you remove the window, you will create a lot of extra work, because the window opening will have to be covered by some other means until you install a replacement. Don't assume your replacement will be in stock; it may have to be specially ordered.

2. Remove the current window if it is damaged. This is especially important if the glass or metal frame is broken. You will need to get close to the window in order to measure, and shards of glass or metal can pose a hazard if left exposed. Once the window has been removed, looked for any stray pieces of glass or metal and vacuum the area to clean up any small shards. Once you have taken your measurements, cover the opening with wood or plastic until you have found a replacement.

3. Take all measurements from inside the building. Measure between the side window jambs. The jamb is the second layer of wood going out from the inside of the window frame. The first, narrow piece of wood you come to is the stop. Do not measure from the stop or your window will be too small. Take three measurements across the window from jamb to jamb to get the most accurate measurement. Take one at the top of the window frame, one in the center and one at the bottom of the opening. Use the smallest of the three measurements as your width.

4. Take a vertical measurement. Hold one end of the tape at the top of the window sill and measure up to the top of the opening. Again, take three measurements, one at the left, one in the center and one on the right side of the window. The smallest measurement should be used as the window height.

5. Use the height and width measurements to order a replacement window.

References

• Lowes
• P.J. Smith Distributors