Premium Soft Type Foam Backer Rod – Versatile Gap & Joint Filler for Home, Concrete Cracks, Expansion Joints, Sealing, Caulk Saver, Crafts - 7/8 Inch x 35 Feet

Soft, Flexible Design – Bi-cellular polyethylene construction easily conforms to irregular or varying joint widths, ideal where standard closed-cell rods aren’t suitable. Durable, Weather-Resistant Backer Rod for Concrete & Home Projects Our high-quality foam backer rod is crafted from durable, weather-resistant materials designed to deliver long-lasting performance in both indoor and outdoor applications. Its flexible, round-foam construction compresses easily while maintaining the firmness needed to create a reliable seal—making it ideal for filling concrete cracks, expansion joints, and medium-sized gaps around the home. Reliable Gap Filler for Caulking & Draft Prevention Use this dependable foam filler to establish a solid base before applying caulk, ensuring improved adhesion and long-term resilience. It seals gaps tightly to prevent drafts, dust, and moisture from entering your home. Whether you’re repairing old, cracked caulk or addressing new openings, this cost-effective backer rod helps reduce the amount of sealant needed while delivering a cleaner, more professional finish. Sealant-Friendly – Works with most cold-applied sealants including urethane, silicone, acrylic, butyl, polysulfides, latex, and chinking; prevents adhesion for proper joint performance. Customizable Lengths & Sizes for Any Project Available in multiple diameters, this foam rope can be easily trimmed with scissors or a blade to match your project’s exact needs. Twist multiple strands together for larger openings, or use single lengths for standard cracks. It’s perfect for concrete and asphalt joints, driveway and sidewalk expansion gaps, wall seams, window and door frames, and countless other applications. Fast, Effortless Installation Installation is simple: clean the area, press the foam rod uniformly into the gap, and apply your preferred caulk or sealant over the top. The foam seats snugly, stays in place, and helps you achieve a smooth, uniform finish—no messy adhesives needed. Durable & Reliable – Water-resistant outer skin, -90°F to 190°F temperature range, >97% compression recovery, meets ASTM C1330 Type B standards. Versatile Beyond Construction While excellent for professional sealing and insulation tasks, this foam is also useful for DIY and creative projects. Use it for weatherproofing, damp-proofing, insulating gaps, supporting dog ears during training, creating craft pieces, ring holders, and more.

Soft Type Backer Rod is a soft, non-gassing, pliable, bi-cellular backup material for construction joints and applications that require sealants. It performs as a depth control for most known cold applied sealants and also helps sealant to assume the optimum hour-glass shape. Sealants will not adhere to it; no bond breaker is required.  Soft Type Backer Rod is a round, black, extruded bi-cellular polyethylene backer rod with a water resistant outer skin. It is compatible with most known cold applied sealants such as urethane, silicone, acrylic, butyl, polysulfides, latex, and chinking sealants.

Specific Uses Include: Especially suited for applications with irregular and varying joint widths where standard closed cell backer rods are not appropriate and where bubbling concerns are critical. May also be used in place of standard closed-cell backer rod in most applications.  Common applications include expansion and contraction joints, window glazing, curtain wall construction partitions, parking decks, bridge and highway construction pavement maintenance, and log home chinking.

Limitations: Do not use with hot-applied sealants. Sealant compatibility should be confirmed by the sealant manufacturer. Backer Rod should be installed with a roller or blunt, flat-sided tool. Avoid puncturing, stretching and over compression.
Temperature Limits: -90"F to 190"F

Installation: Joint or opening must be free of all contaminants (including curing compounds and form-release agents), loose materials, dry and free of frost. Install between 25% - 50% compression. With a blunt instrument or roller, seat the Backer Rod to depth recommended by sealant manufacturer.

Product will not stain or adhere to sealants. Density: 1.6-2.0 lbs./ft3  Water Absorption: less than 0.03 grams/cc  Compression Recovery: > 97% Tensile Strength: > 25-50 psi Meets or exceeds requirements of ASTM C1330 type B