Pre-cured joint sealants are produced by extruding sealant material and allowing it to cure to a rubbery, elastomeric product in a controlled manufacturing environment. Pre-cured joint sealants are packaged in cured form, often in rolls, instead of typical liquid form packaging (tubes, pails, etc.). Pre-cured joint sealants are installed using a thin layer of wet sealant on each side as the adhesive to attach the material to the substrate being sealed. With the outer edges adhered to the substrate, the middle of the pre-cured sealant, which is not bonded to the substrate, acts as the area for expansion and contraction.
First, because of their molecular structure and high bond energy, silicones have excellent aging characteristics and are more resistant to ultra-violet light and weathering than organic materials such as polyurethanes, giving silicone a much longer effective lifespan than these organic materials. Because silicones do not degrade when exposed to the elements, it is possible for manufacturers to produce the material very thin (1 to 2 mm). Thin pre-cured joint sealant minimizes expansion and contraction forces on the substrate and creates the pleasing appearance of a flat profile.