How to Install the Rubber on Glass House Windows

Broken seals along a window pane and frame allow heat to escape in the winter and cool air to escape in the summer. Air leaks can cause windows to fog or frost on a regular basis. For older style homes, a rubber seal may sit between the aluminum window frame and cabin top, or upper frame enclosure. Installing a new rubber seal can help prolong a window’s usefulness and save money in window replacement costs.

A rubber seal helps create a tight fit between the window and its enclosure.

Step 1

Remove the window and frame from its enclosure. Different style windows use sill latches or pulley systems, so removal methods may vary.

Step 2

Scrape and clean off glue or mastic materials from the aluminum frame and from the top of the window enclosure. Use VC thinner or acetone in hard to clean areas.

Step 3

Pull off the old rubber seal with a pair of needle-nose pliers. Scrape off any remaining rubber and glue materials from the aluminum frame and cabin using a razor blade.

Step 4

Draw a pencil line across the cabin top to mark where the frame fits for when it comes time to reinstall the frame.

Step 5

Lay the butyl rubber seal across the backside of the aluminum frame. The seal should span across the top, sides and bottom of the frame so the two ends form a tight, snug fit at the bottom. Avoid stretching out the rubber seal in the process.

Step 6

Reinstall the window.


  • Wear goggles and rubber gloves when using acetone or VC thinner as a safety precaution.