From which backer rod to use for sealant joints to how to install backer rods, learn the purpose of backer rod and proper backer rod installation here.
What is a Backer Rod? How do I Install It? A backer rod is an integral component of sealant joints, it provides three main functions that allow the sealant joint to perform.
The backer rod comes in three main types, closed cell, open cell, and a hybrid that has closed outer cells but open interior cells. Each one of these types of backer rod has its own niche that it thrives in.
Open cell backer rod is great in terms of application, it is very easy to compress and in can even help facilitate the cure of the sealant from both sides instead of an outside to inside direction, or top down.
Typically sealants will cure through a reaction with atmospheric moisture or evaporation. Using a permeable backer rod will allow the sealant to react with atmospheric moisture to cure on the interior side.
Open cell backer rod should not be used in flat or horizontal joints that can have water ponding on them as they can wick moisture to the underside of the sealant.
The hybrid style backer rod is easy to install with the internal open cell structure it can compress easily. Since the backer rod has a closed cell exterior it can be installed in horizontal or flat work because it won’t wick moisture through itself.
As mentioned previously each backer rod has its own niche that it excels in and this information should be considered when selecting your backer rod for you next sealant project.