Sika

Backing rod goes into the joint before the sealant. It sets the depth of the sealant bead and acts as a bond breaker so the sealant grips only the two joint faces rather than the base of the joint. Use it in any moving joint you intend to seal, including slab control joints, perimeter joints and gaps around penetrations. Abelrod is the closed cell gap filler we carry for this work.

Without a rod the sealant bonds to three sides of the joint. That prevents it stretching and compressing as the joint moves, so the bead tends to split or peel away well before it should. You also burn through far more sealant than you need, because the material simply runs down into the void. Fitting rod first is a lot cheaper than coming back to reseal.

Abelrod is a round closed cell rod that sits behind a sealant bead to control bead depth and break the bond to the base of the joint. Abelflex is a flat strip of expansion joint filler used to form and fill the movement joint itself, typically between slabs or where a slab meets another element. Plenty of jobs use both, with Abelflex forming the joint and Abelrod tucked in under the sealant at the surface.

Closed cell rod such as Abelrod suits most common construction sealants, including polyurethanes and hybrids. What matters is that the rod is not punctured during installation and that your sealant is compatible with a closed cell backer. Check the sealant manufacturer's instructions before you start, because some products specifically call for an open cell or bond breaker tape approach instead.

The two biggest are selecting a rod too small for the gap, so it drifts or floats as you tool the bead, and puncturing the rod with a screwdriver or trowel while pushing it in. Both let sealant bond where it should not, or trap air behind the bead. Roll the rod in with a blunt tool, keep it at an even depth right along the joint, and make sure the joint faces are clean and dry before you seal.

Choose a rod slightly larger than the gap so it compresses in and stays put without being forced. Too loose and it shifts while you tool the sealant, too tight and it distorts or tears going in. We list Abelrod in more than one diameter so you can match the joints you are sealing, and the joint depth to width ratio in your sealant's technical data sheet is the right place to work back from. Joint design on Australian external waterproofing work is commonly guided by standards such as AS 4654, so check the project specification as well.

Everything in the Sika range we carry is listed on this page, covering Abelrod closed cell gap filler, Abelflex expansion joint filler foam and the Sika measuring jug, and it ships Australia wide from our warehouse. Rod and joint filler are sold as trade rolls and lengths rather than offcuts, so order them alongside your sealant and save yourself a second delivery. If you are unsure which Abelrod diameter suits the joints on your job, call the team before you order and we will run through it with you.