Which waterproofing system forms a continuous barrier by applying a liquid material to the deck surface?

• A. Sheet system waterproofing
• B. Liquid system waterproofing
• C. Mastic asphalt system waterproofing
• D. Rubber joints

Answer: (B)

Liquid system waterproofing creates a monolithic, seamless barrier by coating the deck surface with a liquid material that cures into a continuous film. Because it is applied as one film (whether spray, roll, or brush), it can cover irregularities and penetrations without seams, providing a single, watertight layer across the entire deck.

Sheet membranes rely on pre-formed sheets with joints that must be sealed, so leaks can occur at seams. Mastic asphalt involves applying a thick, hot-applied asphalt layer rather than a true uniform liquid film, so it doesn’t form the same continuous liquid coating across the surface. Rubber joints are not a deck waterproofing system themselves; they’re expansion-joint components rather than a continuous waterproofing layer.