What are the two types of mastics?

• A. Water-based and Acrylic-based
• B. Solvent-based and Water-based
• C. Solvent-based and Acrylic-based
• D. Solvent-based and Silicone-based

Answer: (B)

Mastics are grouped by the carrier liquid that carries the polymer as they cure. The two broad categories are solvent-based and water-based.

Solvent-based mastics use organic solvents to carry the polymer; as the solvent evaporates, the sealant hardens. They typically provide strong adhesion and durability in outdoor or jointed areas but come with higher VOCs, stronger odor, and more challenging cleanup.

Water-based mastics use water as the carrier; they’re generally easier to apply, cleaner to work with, and have lower odor and VOCs, making them common for interior work. However, depending on the formulation, they may have different performance in moisture resistance or extreme temperatures.

Chemistries like acrylic-based or silicone-based describe the polymer itself, and products can be formulated in either solvent or water bases, but the broad two-category division most often taught is solvent-based versus water-based.