1/2 In Gray Poly Foam Backer Rod, 20 Ft — Moisture-resistant Gap Filler For Joints & Cracks

Presenting the 1/2-inch Gray Poly Foam Backer Rod, a versatile essential for renovations, new builds, and DIY projects. Crafted from durable poly foam, this backer rod compresses smoothly to back sealants, creating a stable base that prevents squeezing and ensures clean, long-lasting joints. The gray color helps it disappear into concrete, masonry, siding, and framing while the lightweight roll is easy to transport and cut to length as needed. With a 20-foot length, it covers sizable openings and reduces wastage while standing up to moisture for reliable performance in diverse environments.

Benefits at a glance: It stabilizes caulk placement, improves adhesion, and minimizes cracking due to substrate movement. Its moisture resistance shields against water intrusion, extending service life for outdoor installations and damp interiors, making it a smart choice for both construction crews and DIY enthusiasts.

• 0.5 inch diameter backer rod for larger gaps and joints in concrete, masonry, and siding, providing a dependable seal base
• 20-foot roll minimizes splices and speeds up installation on long runs for walls, foundations, and exterior openings
• Gray color blends with concrete, plaster, siding, and trim for a discreet, professional finish
• Durable poly foam material delivers flexible backing with stable shape, ideal for durable caulk backing and precise sealant performance
• Moisture-resistant design reduces water exposure, mold risk, and material breakdown in indoor and outdoor applications

Why This Backer Rod Stands Out: This backer rod delivers dependable gap filling, reduces the amount of sealant needed, and enhances overall joint durability across a wide range of building surfaces and climates.