- 1). Clean the edges and top surface of the two adjoining materials with a shop brush. Remove any loose dirt or other debris from the edges and top surfaces.
- 2). Wash the adjoining materials with a cloth rag and a bucket of soapy water. Make sure that the surfaces are completely clean. Rinse the surfaces with water and allow them to dry completely.
- 3). Insert a non-rigid sealant backer against the backing material between the adjoining materials and press it firmly in place. Trim off the excess backer with a utility knife. The backer will prevent the silicone from adhering to the backing material, which would cause a poorly-sealed joint as the materials expand and contract.
- 4). Clip off the end of the point on the silicone caulk tube with the built-in cutter on the caulk gun at a 45-degree angle. Insert the seal cutter on the gun into the tip of the caulk tube to break the seal.
- 5). Insert the tube of silicone into the caulk gun tip first and pivot the back end into place. Squeeze the trigger to advance the plunger in the gun so that it contacts the back of the tube.
- 6). Align the point of the silicone tube between the adjoining materials and squeeze the trigger to apply silicone to the joint. Move the caulk gun along the joint at the same time as you squeeze the trigger so that an even amount of silicone is applied along the entire joint.
- 7). Drag a squeegee across the surface of the joint to remove any excess silicone in order to smooth it out and ensure an even adhesion.