Triple Guard Sill Seal
Triple Guard's combination of thicker foam, adhesive, and T-shape results in a nearly airtight seal for a tricky transition
Irregular concrete foundations can leave houses with gaps between the concrete and the wall plates, which are difficult to seal using conventional 1⁄4-in.-thick foam seals. Protecto Wrap, manufacturer of flexible flashing products, offers Triple Guard, a thicker T-shaped sill seal to bridge those gaps.
Made from 3⁄8-in.-thick closed-cell polyethylene foam bonded to a layer of 20-mil peeland-stick rubberized asphalt, Triple Guard forms a gasket that adheres to the top of the concrete foundation. The bottom half of the sill seal’s T-shaped cross section adheres to the outside face of the concrete foundation, and once the walls are framed, the top half adheres to the wall sheathing. The combination of thicker foam, adhesive, and T-shape results in a nearly airtight seal for a tricky transition.
When tested at the Oak Ridge National Laboratory, the product showed a 91.7% reduction in air leakage compared to conventional foam sill sealers. I’m told that when the lab technicians completed the testing, it took them more than three hours to remove a 10-ft.-long piece from the frame and concrete.
Triple Guard is sold in 25-ft. rolls in 4-3⁄4-in. and 5-1⁄2-in. widths, for use with 2×4 and 2×6 sill plates, respectively. Internet pricing for the 5-1⁄2-in. roll is about $70.