How to Repair Thermal Windows

Thermal windows are a great and energy efficient addition to any home, however, as most homeowners know and can tell you, things go wrong. When they do, you can be ready to repair thermal windows on your own home.

Start With a Clean Slate

This may seem obvious, but the first step to repairing your thermal windows is making sure the surface is clean. This includes the window sill, frame, and surrounding area. Keep in mind that the seal is the most important part of your window repair, which means the area needs to be spotless to make sure dirt and debris can't sneak in to sabotage your repair job. Use an ammonia-based cleaner and a lint-free rag to do the job.

Once you've painstakingly cleaned the area, its time to dry-fit the new window. Slide it straight back for a plumb fit. If the window is too large, you can shave the window itself, or sand down the window sill with a planer, making sure to consistently check the fit.

Caulking and Hanging

When you've got the right fit, the next step is silicone caulking. Place the caulking around the frame and then around the replacement window. When the caulking is in place, carefully hang the window straight back into the existing frame.

Check the fit of the window, it should be plumb. Clean out any excess caulking that may have oozed out during this process. When you are satisfied with a flush-hanging thermal window, nail the thermal window flange to the sides, top, and bottom of the frame for a secure hang. During this step, check regularly to make sure the hang is properly aligned to allow the new window to open and close smoothly.

Flawless Window Frame

For the finishing touches to thermal window repair, attach window trim pieces. Look around for damage to the window frame that may have occurred during your repair, and address those before attaching, or reattaching the window trip pieces. When you're satisfied, you can move on to sanding and repainting for a flawless thermal window repair job.