Contemporary foam sealants are loaded with feature-rich attributes. They seal quickly, with a cell type that prevents fluid ingress. Temperature control and vibration management strategies are readily formed when the foam material is intelligently sourced and expertly installed. Think about it, these adhesives and binding materials bond efficiently, so what else is there to think about? Well, what about a sealing scenario where part of the backing surface is missing?
Backing Rods Fill the Void
Like a gap-filling backbone, the backing rods occupy any and all spatial voids. Picture a series of garages behind a busy street. Water seepage problems are taking place between two units because of a crack in the wall. The obvious solution here is to close this gap at its source. Unfortunately, the gap is several centimetres wide. On the bright side, there’s a sealant that’s up to the job, but it’s not going to properly fill the gap. That’s a job for the backing rods. Properly inserted, the pliable strip fills that linearly stretching gap. Then, once the void is occupied, the foam sealant has a backing surface it can be pushed against. That final joint is strong and entirely weatherproof.
Creating a Three-Walled Joint
If the backing rod isn’t fitted, the sealing material is compressed between two walls, the chasm of the joint, as it were. The third surface is missing. Arguably, the compressed caulking will expand to fill the void. However, it has no third wall to occupy. Because of that absent backing surface, the foam sealant doesn’t have a ‘backbone,’ the one we mentioned a moment ago. It is absolutely imperative that the three-way surface joint forms correctly, so that third surface, the one created by the backing rod, must be installed before the foam sealant is applied. Otherwise, application uniformity cannot be correctly established. Keep these facts in mind while installing this material stripping as an expansion joint before an amorphous sealant is applied.
Employed in the construction industry as an expansion jointing solution, backing rods are weatherproof. They’re made from polyurethane and other tough engineering plastics, plus they’re entirely fireproof, as mandated by all relevant building codes. Of course, this tough plastic piping isn’t designed to function without assistance. Indeed, the backing label provides a clue as to its true purpose. When the backing rods are fitted as construction joints, between two wall joining sites, the foam sealant compound enters the linear depression as an optimally prepped adhesive binder. Essentially, that solid backing acts as a bracing surface for the putty-like compound.