Backer Rod (Open-Cell)

JTBR2000 to 2040 - Open Cell Backing Rod.jpg
JTBR2000 to 2040 - Open Cell Backing Rod.jpg

Backer Rod (Open-Cell)


Open Cell Backer Rod, also known as backing rod is a compressible open-cell foam rod used to fill expansion joints. Backer rod supports the caulking compound (joint sealant) as it dries on top, and also provides additional expansion capabilities.

Open cell backer rod is generally more popular than closed cell, as it is more pliable, allows the joint to ‘breathe’ ensuring no air bubbles form in the joint sealant, and speeds up the sealant curing time.

Open cell is usually orange or grey in colour, and is commonly used between pre-cast panels, or in joints on large concrete slabs. In terms of choosing the correct diameter backing rod, select a size which is slightly larger than the joint width – to ensure a secure fit.

Use As a bond breaker/joint profile former to support elastomeric sealants in expansion joints between all common building materials.


  • Compatible with all elastomeric sealants.

  • Open cell structure allows greater air contact with joint sealants resulting in faster cure rate of single component joint sealants.

  • Readily compressible - each size accommodates a wide range of joint sizes.

  • Low load transfer.

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