Which waterproofing type uses liquid-applied materials sprayed or spread to form a continuous protective barrier on the deck surface?

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

Answer: (A)

Liquid-applied waterproofing forms a continuous barrier because the coating is applied as a liquid that bonds to the deck surface and cures into a single, monolithic membrane. It can be sprayed or spread by roller or brush, which lets it conform to the deck’s irregularities and edges without seams. Once cured, it becomes a flexible, crack-bridging layer that protects the surface from water intrusion and can be repaired or re-coated more easily than sheet-based systems. This is in contrast to sheet system waterproofing, which uses pre-formed sheets with seams that must be sealed, and to mastic asphalt systems, which rely on asphalt-based materials often installed with heat, not sprayed or brushed on as a liquid. Bridge expansion joints are structural joints rather than a waterproofing type.