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Types Of Backer Rods And Their Applications

March 09, 2022

Backer rods are flexible, cylindrical polyethylene foam tubes used to fill the gap between two joints. These cylindrical tubes do an excellent job of sealing joints by forming a strong bond with caulking material. 

The foam rods get their name because they provide "backing" which helps limit the amount of caulking material being used for effectively fixing cracks.


These flexible rods come in different sizes and can be used for fixing cracks of different sizes. Using these rods guarantees that the structural integrity of a structure is not compromised.


Types of backer rods

An open-cell rod is best for fixing cracks in the interior of a house as these rods offer unrestricted airflow, which in turn increases their capacity to retain their original shape. This particular feature makes open-cell rods perfect for applications in areas where a lot of movement or compression is expected.

 Following are some areas of applications of open-cell rods

  • Parking decks
  • Expansion joints

  • Contraction joints

  • Partition walls

  • Curtain walls


As the name suggests, in this type of backer rod, each cell is completely closed and is not interlinked with each other. This particular feature makes this type of rod more resistant to moisture and water. The bonding surface area of closed-cell rods is better than open-cell rods. Closed-cell rods are generally more suitable for outdoor purposes.


Following are some areas of applications of closed-cell rods

  • Pavement cracks
  • Driveway cracks
  • Window and door applications


Bi-cellular rods offer the best of both worlds. In this type, you get the compression ability and the flexibility of an open-cell rod and at the same time, they resist moisture and water as competently as the closed-cell rod. Bi-cellular rods are perfect for irregular joint applications.

For the best backer rods, you can rely on Alcot Plastics. Our wide range of products includes top-of-the-line pool noodles, screening splines, and more.