7/8" Kool-Rod Backer Foam For Deck-O-Seal Installation | 1 Foot | 4650875

Manufactured by W. R. Meadows, Kool-Rod 4650875 is a 7/8-inch closed-cell polyethylene foam backer rod engineered specifically for use with Deck-O-Seal and other cold-applied pool deck joint sealants. Sold per lineal foot, it presses into pool coping-to-deck expansion joints and cantilever decking joints to control sealant depth, establish the correct 2:1 width-to-depth joint ratio, and prevent sealant from over-filling the joint cavity or sinking down into it. The 7/8-inch diameter is sized for slightly narrower expansion joints where a full 1-inch backer rod would be too wide to compress cleanly into place. Because the foam is closed-cell, it is virtually non-absorbent and chemically inert to most solvents, meaning it will not soak up moisture, trap air, or bond to the sealant above it — three factors commonly tied to three-sided adhesion failure and reduced joint life. The 4650875 is fully compatible with acrylic, butyl, polyurethane, polysulfide, silicone, and most other cold-applied sealant compounds, and it cuts to length or compresses into place with a blunt instrument or roller using no special tools.

Highlights

• Properly Sized for Slightly Narrower Joints: The 7/8-inch diameter targets pool deck and coping expansion joints that are slightly too narrow for a 1-inch rod, where forcing a larger rod into place would cause over-compression or seating issues — selecting a rod diameter slightly larger than the joint width is the proper rule of thumb for a secure, tightly held fit.
• Controls Sealant Depth for Proper Joint Geometry: Installed below the sealant, Kool-Rod sets the correct 2:1 width-to-depth joint ratio recommended for Deck-O-Seal and other cold-applied pool deck sealants, locking in the geometry the joint needs to perform reliably under the freeze-thaw cycles and movement typical of pool deck environments.
• Closed-Cell Construction Stays Dry: A closed-cell polyethylene foam structure is virtually non-absorbent and prevents air or moisture from becoming trapped between the backer rod and the sealant above, removing one of the most common contributors to premature joint seal failure on pool coping and deck expansion joints exposed to weather.
• Non-Bonding to Cold-Applied Sealants: Kool-Rod will not adhere to any cold-applied sealant compound, ensuring the sealant bonds only to the two joint faces rather than to the backer rod underneath, preserving the proper two-sided adhesion configuration that allows the sealant to stretch and compress with the joint without tearing.
• Works with Major Cold-Applied Sealants: Fully compatible with acrylic, butyl, polyurethane, polysulfide, silicone, and most other cold-applied sealant compounds, including the full Deck-O-Seal product line, making the 4650875 a dependable backer rod choice across a wide range of pool deck, coping, and expansion joint sealing applications.