Backer rod products are classified into two categories that are depending on the density of the foam used. These are:
Open-cell
Closed-cell
These backer rods can be used interchangeably and are mostly used to improve durability and appearance of many different projects. Open-cell rods are majorly used for indoor purposes where there is little moisture while the closed-cell rods are used for outdoor purposes majorly in driveways.
Open-cell backer rod
Here, the foam material is usually breathable and hairy. Open-cell rods are easy to install because they are very pliable and soft and are used for indoor environments where there is little moisture. These rods are universal since they can be used to close cracks in concrete that vary in sizes by compressing them. A “dull” putty knife is used for this installation without damaging the rod. An example of the open-cell rod is the OCFoam which is a polyurethane rod used in window glazing and other projects which require polyurethane sealants.
Closed-cell rods
Are commonly used in outdoor environments majorly in driveways. This type of backer rod has denser and firmer foam than the open-cell that makes it harder to bend and maneuver making it usable for heavier-duty settings. These rods are used for smaller joints and have a higher insulative power for moisture than the open-cell rods. The closed-cell version provides a firm finish and can be used in place with adhesive spray.
These two versions of backer rods enable building materials to bend, flex and move depending on the environmental conditions they are exposed to, such as moisture, heat, wind and UV exposure. In most cases, the caulking sealants are flexible sticking onto the building material instead of the rod for a long time. Alcot plastic company provides these two types of rods to meet its clients’ needs.