The 3 primary Backer Rods and their functions

Backer rods are an essential source of support for joints and used to fill up spaces in between building materials such as tiles and corners. They are flexible lengths of foam that are used as a backing in joints. They are also used as filling in panelling, tiling, flooring and more. Due to the nature of its use and the various shapes and sizes they come in, it is important to know exactly what you will need them for and choose the right ones accordingly.

Let us look at the types of backer rods and their specific uses.

The Open-Cell Rod

These rods are unique in that they can easily be compressed into any shape and will return to their original state. The flexibility makes them useful for sealing applications while also helping limit the depth of sealant. This type of rod also helps with airing the sealant, which prevents the sealant from cracking due to drying up.

These rods are used for contraction and expansion joints, window glazing, curtain walls, parking decks and other similar uses.

The Closed-Cell Rod

These backers, as the name implies, are built with closed-cell foam and do not interconnect with other cells. This feature means that these rods will not wick moisture, making them highly suitable for wet and damp conditions. Sealants, caulking or other chinking materials adhere better to closed-cell rods, which have a better bonding surface. 

Uses for these backer rods include partitions, log construction, pavement joint repairs, pre-cast units and copings.

Hybrid or Bi-Cellular rods

These rods combine both open and closed cell foam structures and their use is a bit more unique than the other two rods. Hybrid rods are ideal for irregular joint applications where self-levelling, flow able sealants are used. They are the go-to rods when bubbling is a problem. The construction of these rods allows them to be flexible while also being resistant to moisture.