The most important tips to keep in mind when installing do-it-yourself windows are to inspect the existing window, measure carefully, choose the right type of replacement window for the window opening, and to thoroughly seal all openings and points of contact to protect against the entrance of moisture. Proper installation is crucial to keeping moisture out of wall cavities and preventing mold growth, heat loss, and rot. Correctly installed do-it-yourself windows can greatly improve a home’s appearance and energy efficiency.
There are three types of replacement windows: sash kits, insert replacements, and full frame units. Sash kits consist of new jamb liners, sash, and moving parts of the window and mount inside the existing jamb. Insert replacements, also called pocket windows, are fully assembled windows that include new jambs and liners. When installed, the glass area will be smaller than with the previous window because there are new parts fitting inside the existing jambs. Full frame units are like inserts that contain the complete window frame.
Before purchasing do-it-yourself windows, it’s important to inspect the existing jambs, sills, and frames for signs of water damage and rot. If there is damage in these areas, rotten wood will have to be completely removed. The window should be replaced with a full frame replacement window unit because these include parts that sash kits and insert replacement do not contain.
Once the existing window has been inspected, measure the window carefully. Do-it-yourself windows are custom-built and non-refundable once purchased, so accurate measurements will prevent expensive mistakes. To determine width, measure between the side jambs at the top, middle, and bottom of the window. Use the smallest measurement of the three measurements. Height should be measured from the top surface of the sloped sill to the head jamb.
When ready to install do-it-yourself windows, remove old windows. Do-it-yourself windows should always be installed according to the manufacturer’s instructions to preserve the warranty. If a house was built before 1978, there may be lead-based paint present, so proper precautions should be taken to minimize exposure.
Caulk the inside edges of the window frame before fitting the new window. Place the new window in the frame, making sure all openings are completely level and square. If they are not, add shims and keep adjusting until the new window is straight, fits snugly, and sashes move smoothly. The new window should be firmly screwed into place. Applying insulating foam will help seal any gaps and weatherproof the replacement window.