Many would ask why there is a need for a backing material for the application of sealant. While most general purpose caulks never require the use of a backing material, the fact is that when applied to wood, the sealant will perform better if a backer rod or other backing material is used. The use of this material serves two functions. First is to ensure that the sealant has the right thickness for it to stretch and contract without getting damaged. Second is to give the sealant an appropriate surface to stick on so that it won’t tear away from the wood when it stretches.
Sealing the exterior joint or crack in wood and other materials works the same no matter the width of the gap is. In case the sealant that is applied on the gap is too thick, it can’t stretch enough to compensate for the shrinking of wood and may cause damage. Similarly, if the sealant is too thin, it will break upon stretching. The principle here is comparable to that of a rubber band. This is where the use of a backing material like backer rod becomes very important. This material has to be inert and won’t react with the sealant. Plus, it should not deform when the sealant is applied over it. More importantly, the backer rod should be able to withstand high temperatures without distorting.
While there are other backing materials available to support the sealant, a round backer rod is best to use for smaller joints, cracks, and gaps. It is highly flexible that you can push it into a crevice without the aid of a staple or a nail. Backer rod also comes in a wide range of sizes and is inexpensive. It is available in various types as well. Some types can provide a flat surface for sealing or chinking while others work best in providing the needed protection against the effects of weather elements. If you are not sure about the proper backing material to use for your application, just get in touch with us and one of our experts will be more than happy to help you.