CFI Tile & Stone Installation 2

Question 1

What is the minimum recommended grout joint width for rectified porcelain tiles?

Accepted Answer

1/16 inch

Answer

Rectified tiles have precise, uniform edges allowing grout joints as narrow as 1/16 inch.

Question 2

When installing large-format tiles (24"x24" or larger), which trowel method is recommended to ensure full mortar coverage?

Accepted Answer

Back-buttering combined with substrate troweling

Answer

Large-format tiles require both back-buttering and substrate troweling to achieve the required 95% mortar contact.

Question 3

What does ANSI A108.02 specify as the minimum bond coat coverage for tile installed in wet areas?

Accepted Answer

95%

Answer

ANSI A108.02 requires 95% mortar coverage for tiles in wet areas, exterior applications, and for large-format tiles.

Question 4

Which type of membrane is most appropriate for waterproofing a shower floor prior to tile installation?

Accepted Answer

Fabric-reinforced liquid-applied waterproof membrane

Answer

Fabric-reinforced liquid-applied membranes create a continuous waterproof barrier that fully bonds to the substrate.

Question 5

What is the purpose of a cleavage membrane (like 15-lb felt) installed beneath a mortar bed?

Accepted Answer

To allow the mortar bed to float independently of the substrate

Answer

A cleavage membrane allows the mortar bed to move independently, preventing cracks in the substrate from telegraphing through.

(CFI) Certified Flooring Installer Practice Test