3/8" Closed Cell Backer Rod - 3600' Case

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CRL EF38B 3/8" Closed Cell Backer Rod - 3600' Case

Item #: EF38B by CR Laurence

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In Stock $297.59 /case

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  • Helps control sealant thickness easily.
  • Doesn't stick to sealants; no need for bond breaker.
  • Works with all cold-applied sealants.

Feet per Bulk Case

3,600 ft (1,097 m)

Diameter of Rod

3/8 in (9.5 mm)

Roll Length

3,600' (1,097 m)

Rod Diameter

3/8" (10 mm)

Case Length

3,600' (1,097 m)






Closed Cell



Roll Length (Feet)


CRL Closed Cell Backer Rod is a flexible, round polyethylene foam with an outer "skin" designed to serve as a backing and thickness control device for elastomeric and other cold-applied sealants. It seamlessly integrates into the joint it's placed in and is available in various diameters to accommodate joints ranging from 3/16" to 1-5/8" (5 to 41 mm). This helps regulate sealant depth, preventing excessive sealant use and ensuring proper joint design. As the sealant doesn't adhere to the rod's "skin," it can expand and contract with joint movement, minimizing stress on adhesion points to the substrate. CRL Closed Cell Backer Rod is hydrophobic and won't absorb or transfer water to joint walls, which could compromise adhesive strength. It's compatible with cold-applied sealants and encourages the preferred "hourglass" shape for joint sealants due to its round shape. It can withstand extreme temperatures, ranging from -45° to 160°F (-43° to 71°C). This product is chemically inert and resistant to oils, gasoline, and solvents. It won't discolor or bleed into the sealant material. Typically used in expansion/control joints where cold-applied sealants are employed, these joints are commonly found in curtain walls, construction partitions, precast panels, parking decks, door and window frame perimeters, coping, floor and deck joints, horizontal traffic joints, and building rehabilitation projects. Selecting the appropriate size of CRL Closed Cell Backer Rod is crucial as it dictates the sealant bead's depth. It should be about 25% wider than the joint to fit snugly and act as a bond breaker, preventing sealant adhesion on the underside. Always use a blunt tool or roller for installation, with Cat. No. SBRR Backer Rod Roller specifically designed for smooth backer rod installation of all types.