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

Kool-Rod 4650875 is a 7/8-inch closed-cell polyethylene foam backer rod manufactured by W. R. Meadows, specifically designed for use with Deck-O-Seal and other cold-applied pool deck joint sealants. Sold per lineal foot, it installs quickly 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 or sinking into the joint cavity. The 7/8-inch diameter is well suited for slightly narrower expansion joints where a full 1-inch rod would be too wide to compress properly into place. The closed-cell foam structure is virtually non-absorbent and chemically inert to most solvents, so it will not absorb moisture, trap air, or bond to the sealant applied above it — eliminating the risk of three-sided adhesion failure that compromises long-term joint performance. Fully compatible with acrylic, butyl, polyurethane, polysulfide, silicone, and most other cold-applied sealant compounds, Kool-Rod can be cut to length or compressed into place with a blunt instrument or roller with no special tools required.

Highlights

• 7/8-Inch Diameter for Narrower Joints: The 7/8-inch diameter is properly sized for slightly narrower pool deck and coping expansion joints where a 1-inch rod would over-compress or resist proper seating, and as a general rule the backer rod diameter should be slightly larger than the joint width to achieve a secure, tightly held fit during installation.
• Sets the Recommended 2:1 Joint Ratio: Installed below the sealant layer, Kool-Rod establishes the correct 2:1 width-to-depth joint ratio recommended for Deck-O-Seal and all cold-applied pool deck sealants, supporting a properly configured joint that performs and seals as intended over the long term against weather and movement.
• Non-Absorbent Closed-Cell Foam: The closed-cell polyethylene structure is virtually non-absorbent and prevents air or moisture from becoming trapped between the backer rod and the sealant above, addressing a common contributor to joint seal failure in pool deck and coping applications exposed to ongoing water and weather cycles.
• Two-Sided Adhesion, No Bond to Sealant: Kool-Rod does not adhere to any cold-applied sealant compound, so the sealant bonds only to the two joint faces rather than to the backer rod beneath it, preserving the correct two-sided adhesion configuration that allows the joint to flex and move with the deck without cracking or delaminating.
• Universal Cold-Applied Sealant Compatibility: 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 reliable single-product backer rod choice across pool deck, coping, and expansion joint sealing projects.