Hard (Closed-Cell) Backer Rod

Hard closed-cell backer rod is an extruded polyethylene foam joint backing with a smooth, non-absorbing skin. It provides a firm, consistent backing for sealant application and tooling, and is the preferred choice for horizontal joints and joints exposed to moisture.

Key Features

• Non-absorbing closed-cell structure – will not wick or hold water
• Firm, resilient backing for consistent tooling
• Bond breaker prevents three-sided adhesion
• Controls sealant depth and reduces material waste
• Compatible with most polyurethane, silicone and hybrid sealants

Typical Applications

• Expansion and control joints in concrete, masonry, precast and curtain wall
• Horizontal and flat joints where water may pond
• Window, door and cladding perimeter joints

Sizes & Packaging

Joint widths are approximate, based on the standard practice of sizing backer rod about 25% larger than the joint width.

Installation Notes

• Clean and dry the joint before installation.
• Size the rod about 25% larger than the joint so it stays in place under compression.
• Insert with a blunt, rounded tool – never a screwdriver or knife. Punctured cells can outgas and cause bubbles in the sealant.
• Set depth to the sealant manufacturer’s recommended width-to-depth ratio (typically about 2:1).
• Do not stretch or twist the rod during installation.
• Follow the sealant manufacturer’s installation guidelines and confirm compatibility.