About Master Flow™ Foundation Vents - Block Style

The GAF Master Flow™ BVSII block style foundation vent with moveable louvers allows air circulation to help reduce moisture that can cause decay in your foundation with a net free vent area of 73 sq. in. The block design allows for easy installation and is constructed of galvanized steel and aluminum louvers. The louvers adjust manually.

Features & Benefits

Master Flow™ Foundation Vents - Block Style

Get automatic Lifetime Protection on your entire GAF roofing system

When you install any GAF Lifetime Shingle and at least 3 qualifying GAF accessories, you'll automatically get a Lifetime limited warranty on your shingles and all qualifying GAF accessories*.
*See GAF Shingle & Accessory Ltd. Warranty for complete coverage and restrictions. The word “Lifetime” refers to the length of coverage provided by the GAF Shingle & Accessory Ltd. Warranty, and means as long as the original individual owner(s) of a single-family detached residence [or the second owner(s) in certain circumstances] owns the property where the shingles and accessories are installed. For owners/structures not meeting the above criteria, Lifetime coverage is not applicable. Lifetime ltd. warranty on accessories requires the use of at least three qualifying GAF accessories and the use of Lifetime Shingles.

Product Documentation

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