WHILE SUPPLIES LAST

The following sizes will soon be unavailable. Limited quantities available. Get them while you can!

• 1-1/4" (50' roll)
• 1-1/2" (6' roll)
• 2" (6' roll)

Closed-cell foam backer rods are used behind chinking and caulking. Backer rod is essential for ideal joint design, providing backing for 2-point adhesion to sealants such as caulk or chinking.

A thin layer of sealant stretches much better than a big ol' wad does. If it can't stretch, it will either pull away from the log or pull apart, breaking the seal and increasing energy ($) loss.

The sizing rule for the rod against the gap, and why it goes behind both caulk and chinking, is in Caulk vs. Chinking vs. Backer Rod.