Aluminum foil tape and aluminum flashing tape may look alike, but a closer inspection reveals technical differences that become very important in specific applications. The two types of tape should not be used interchangeably, as design, strength, and weatherproofing characteristics for the disparate adhesive products make them functionally dissimilar and inappropriate for use in select areas.
Aluminum Foil Tape
This thin, foil tape, treated with acrylic adhesive and backed with a removable paper liner, is extremely malleable, giving it the ability to conform itself well to fiberglass duct board and sheet metal ductwork. The product provides an effective vapor seal and withstands temperatures ranging from -25 degrees Fahrenheit to 260 degrees F. Aluminum foil tape is commonly available in 1.5, 2.0 and 3.0 mil thicknesses and widths from 2.5 to 3 inches.
Aluminum Flashing Tape
Flashing tape is a three-ply laminate product designed to be highly resistant to puncture, wear, and cold-weather conditions. This product is used to provide weather-tight installations for windows, doors and roof flashing. Aluminum flashing tape is made with top and bottom outer layers of aluminum foil and a single layer of polyester film at its core. The tape is then coated with a cold-weather acrylic adhesive that allows the product to be pressed into place.
Dimensions For Flashing Tape
Due to its three-ply design, aluminum flashing tape ranges in thickness from 6.5 to 7.5 mils. The tape is available in widths from 2 inches, for window and door applications, up to 6 inches for ease of positioning on roof flashing. Flashing tape withstands temperature ranges from a low of -25 degree F to a high of 180 degree F. Flashing tape may be used as an alternative to rolled or step flashing in roofing applications.
Aluminum foil tape is primarily designed for indoor use, where its ability to conform with aluminum and fiberglass in the presence of extreme heat is its best asset. Strength and wear resistance is less of an issue for aluminum foil tape, so it can be made thin and malleable without compromising effectiveness in its intended use. Aluminum flashing tape, a thicker, stronger product, is designed for the rigors of outdoor use and to be able to handle most weather extremes.
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