CTI Grout & Mortar Systems Flashcards

Which grout type requires mixing two separate components — a resin and a hardener — immediately before application?

Answer: Epoxy grout

Epoxy grout is a two-component system; mixing the resin and hardener triggers a chemical cure rather than the hydration that cures cement-based grouts.

A CTI inspector observes that grout color varies noticeably across a recently completed floor. What is the most likely cause?

Answer: Inconsistent water-to-grout ratios were used during mixing different batches

Varying water ratios change the water-to-cement ratio between batches, resulting in inconsistent color and strength across the installation.

What material must be used to fill movement joints (expansion joints) in a tile installation?

Answer: Silicone or urethane flexible caulk

Movement joints must be filled with a flexible sealant such as silicone or urethane caulk to accommodate thermal and structural movement without cracking.

Which ANSI standard covers dry-set Portland cement mortar (unmodified thinset)?

Answer: ANSI A118.1

ANSI A118.1 establishes performance requirements for dry-set (unmodified) Portland cement mortar, the foundational standard for cement-based tile setting materials.

Which factor is LEAST likely to cause cracking in grout joints of a completed tile installation?

Answer: Grout mixed with slightly less water than recommended

Grout mixed with slightly less water is stiffer but generally produces stronger joints; cracking is more commonly caused by structural movement or premature loading.

Which setting material is required for tile installations subject to continuous water immersion, such as swimming pools?

Answer: Epoxy adhesive (ANSI A118.3)

Epoxy adhesive provides the waterproof, chemically resistant bond required for continuous immersion; cement bonds break down over time under sustained water exposure.