CTI Grouting & Finishing Techniques 5

Question 1

When applying epoxy grout on a hot day with substrate temperatures above 90°F, the installer should expect:

Accepted Answer

Significantly shortened working time requiring smaller batch sizes

Answer

Heat accelerates the chemical curing reaction of epoxy grout, dramatically reducing working time and requiring the installer to mix smaller batches and work in sections.

Question 2

A CTI candidate notices that grout joints in a newly grouted installation are darker in some areas than others even though the same grout batch was used. The most probable cause is:

Accepted Answer

The tiles have varying levels of surface porosity affecting moisture absorption from grout

Answer

Tiles with varying porosity pull moisture out of grout at different rates, causing differential drying rates that produce color variation until the grout fully cures.

Question 3

Which TCNA handbook method specifically addresses the grouting of tile installed over radiant heating systems?

Accepted Answer

EJ171 — movement joint guidelines

Answer

TCNA EJ171 covers movement joint requirements, which are especially critical in radiant heat installations where thermal expansion cycles stress the grout joints continuously.

Question 4

During final cleanup after grouting, the installer uses a damp sponge and notices a thin, cloudy film remains on the tile surface. The most effective next step is to:

Accepted Answer

Allow the haze to dry completely, then buff off with a clean dry cloth

Answer

Light grout haze is best removed by allowing it to dry to a powdery state and then buffing with a clean dry cloth, which is more effective than fighting wet smear.

Question 5

What is the primary reason that caulk is specified at inside corners and perimeter edges instead of grout?

Accepted Answer

Caulk is flexible and accommodates differential movement that would crack rigid grout

Answer

Inside corners and perimeter edges are high-stress locations where structural and thermal movement concentrate; flexible caulk absorbs this movement without cracking, unlike rigid grout.

(CTI) Certified Tile Installer Practice Test

(CTI) Certified Tile Installer Practice Test

CTI Grouting & Finishing Techniques 5