Sawjoints should be filled with which materials?

• A. Gypsum, premolded fillers, silicone
• B. Epoxy resin, asphalt, foam
• C. Wood shims, caulk, silicone
• D. Cementitious grout, epoxy, silicone

Answer: (A)

Saw joints need a filling system that both accommodates panel movement and keeps water out. The best approach uses three parts: a premolded filler to establish and support the correct sealant depth, gypsum as the main fill to occupy most of the joint, and a silicone sealant on the surface to provide a durable, elastic seal. The premolded filler acts as a backing so the sealant isn’t squeezed too thin and can move freely. The silicone is chosen for its long-term elasticity and weather resistance, which is essential for joints that experience temperature changes and movement. Gypsum provides a workable, compatible base fill that pairs with the backing and sealant to complete the joint system. Other material combinations either lack the essential backing to control sealant depth, are too rigid to accommodate movement, or don’t resist weathering well, making them less suitable for saw joints.