Sikaflex is a type of polyurethane sealant that comes in various colors. It is sold in 10.3 oz. tubes and is suitable for making permanent elastic seals with a very high adhesive strength. Sikaflex can be used in a wide range of temperatures, from -40 degrees to 195 degrees Fahrenheit. It hardens completely in 60 minutes and is especially useful for sealing gaps and cracks on the exterior of your house.

Step 1

Wipe down the area where you will be applying the Sikaflex. Dampen a clean cloth with water and scrub thoroughly to remove any dirt, debris or grease from the surface where you will be working.

Step 2

Slide the tube of Sikaflex into a caulk gun. Press it firmly into place so the nozzle is protruding from the front of the caulk gun and the bottom of the tube of Sikaflex is against the bottom of the caulk gun.

Step 3

Cut off the tip of the nozzle at a slight upward angle with a utility knife. This will open a hole for the Sikaflex to flow through. Tape off the area around where you will be caulking with painter's tape. Apply the tape just outside of the seams to prevent the Sikaflex from getting into unwanted areas.

Step 4

Position the tip of the Sikaflex just above the first seam or crack. Press the trigger and run a bead of Sikaflex into the seam. Move the caulk gun along the seam and hold down on the trigger to release the Sikaflex into the entire length of the crack.

Step 5

Wipe away any excess Sikaflex that is not in the crack with a clean cloth. Let it dry for one hour and remove the painter's tape from the area. Repeat the process for any other cracks that need to be filled.