CFI Tile & Stone Installation 4

Question 1

According to the TCNA Handbook, what is the maximum allowable deflection for a subfloor intended for ceramic tile installation?

Accepted Answer

L/360

Answer

The TCNA requires floor deflection not to exceed L/360 of the span length under live load for ceramic tile installations.

Question 2

What is the primary reason diagonal tile layouts require more tile material than straight layouts?

Accepted Answer

More cuts are needed at the perimeter, increasing waste

Answer

Diagonal layouts create angled cuts at all four walls, generating significantly more cut waste than straight grid patterns.

Question 3

When mixing Portland cement mortar for a wall application, what is the correct Portland cement to sand ratio?

Accepted Answer

1:3 to 1:5

Answer

A 1:3 to 1:5 Portland cement to sand ratio is standard for scratch and brown coats on wall applications.

Question 4

What does the term 'back-buttering' refer to in tile installation?

Accepted Answer

Applying mortar to the back face of the tile before setting

Answer

Back-buttering is the technique of spreading a thin coat of mortar on the back of a tile to improve bond and coverage.

Question 5

Which substrate is NOT suitable as a direct bond surface for ceramic tile without additional preparation?

Accepted Answer

Existing vinyl flooring

Answer

Vinyl flooring is too flexible and non-porous for direct tile bonding without proper surface preparation or removal.

(CFI) Certified Flooring Installer Practice Test