Butyl tape is a tacky gasket used to seal glass within a frame. The tackiness of the butyl gasket, seals the area between the glass and frame from air leakage. One thing you need to remember about butyl gasket is that it is not an adhesive; therefore, you cannot use it as a standalone structural sealant. Since butyl gasket is not an adhesive, it remains pliable for years, allowing you to take your time installing the window with butyl tape.
Lay the piece of glass flat on the padded worktable with the side that will contact the butyl tape facing up.
Clean large debris from the surface of the glass by resting the 2-inch wide scraper on the surface of the glass. Tilt the scraper blade at a 15-degree angle, and push the scraper along the edge of the glass.
Spray glass cleaner on the surface of the glass, and wipe the glass with a clean rag to remove contaminants from the glass that will interfere with the adhesion of the butyl tape.
Peel a 6-inch length of butyl tape from the roll, and with it lying flat, press the tape onto the frame that will receive the glass. Ensure that the bottom edge of the butyl tape sits as low as possible in the window frame. Do not tear the butyl tape; install the tape in one continuous length.
Pull additional tape from the roll as needed to continue running the butyl tape around the frame.
Cut the butyl tape from the roll when you reach the point that you started laying the butyl tape on the window frame.
Peel the backing paper from the butyl tape.
Carefully place the glass in the window opening, and press the glass against the window frame to install the butyl tape onto the glass.
Install shims behind the glass to hold it in place while you complete the glass installation.
Do not apply the butyl tape directly to the surface of the glass because the butyl tape will slide from the surface of the glass.