Saw joints should be filled with which materials?

• A. Gypsum, premolded fillers or silicone
• B. Gypsum
• C. Premolded fillers
• D. Silicone

Answer: (A)

Saw joints are controlled cracking planes in concrete that must be able to move slightly without causing damage or leaks. The filler chosen for these joints needs to be non-restrictive to movement and compatible with concrete and any surface finish. Gypsum, premolded fillers, and silicone each serve that purpose in different situations: premolded fillers provide a compressible backfill that accommodates movement; silicone sealant offers a flexible, water-tight seal that can move with the joint; gypsum can be used in certain applications as a filler that supports a flush finish. Because multiple materials can be appropriate depending on the joint’s design and performance requirements, including all of these as acceptable options is the most accurate answer.