Caulk Backer Rod 3/8" x 20'

Optimize your sealant performance with this 3/8" diameter, 20-foot closed-cell foam backer rod. Manufactured by M-D, this non-absorbent polyethylene material serves as an ideal filler for expansion joints, gaps, and openings, ensuring consistent sealant depth and preventing three-sided adhesion. Easy to insert and compressible to fit a variety of joint sizes, it reduces sealant use while enhancing the longevity and flexibility of your caulked assemblies.

Whether you’re working on windows, doors, concrete expansion joints, or masonry cracks, this backer rod delivers a smooth, uniform surface for professional-grade caulking results every time.

Key Features

• Non-absorbent, closed-cell polyethylene foam
• Controls sealant depth and prevents three-sided adhesion
• Compressible for easy installation in joints and gaps
• Ideal for gaps larger than 3/8" (9.5 mm)
• Helps reduce sealant consumption and material waste
• Enhances flexibility and durability of finished seal

⚠️ WARNING: This product can expose you to Carbon-black extracts known to the State of California to cause cancer. For more information, visit www.P65Warnings.ca.gov.