It is quite important to understand some of the properties of a backer rod before using it for construction projects. Basically, there are two versions of rods used to fill all types of joints in constructions. These are the closed cell rods and open cell soft rods. Each of the mentioned types has specific properties that are meant for specific types of joints in various environments. Nevertheless, each one of them is used to form a suitable base for the application of sealants. Some of the specific properties of each type are discussed briefly in the rest of the article.
The open cell backer rod is generally flexible, expandable and pliable in nature. This is due to its internal structure that is made up of open cells. The open cells also make it vulnerable to air and moisture hence making it inappropriate for sealing outdoor joints. It can only be used to fill indoor joints that are free from moisture and other fluids. Because open cell rods are soft and pliable, they can be used to fill numerous types of joints. They are generally easier to install since they can easily conform to complex rugged joints and are easier to use than closed cell versions.
One may wonder how the closed cell rod is used if at all open cell rods are suitable for all types of cracks. Closed cell backer rod is used to fill joints that are found in outdoor environments. This is because it is resistant to water, air, and other fluids that may be either neutral or corrosive in nature. Its structure consists of millions of closed cells that are responsible for the airtight nature. However, they are rigid and are supplied in smaller diameters than soft rods hence appropriate for small joints.