CTI Movement Joints & Expansion Joints 3

Question 1

Which ANSI standard section contains general requirements for movement joints in tile work, complementing TCNA EJ171?

Accepted Answer

ANSI A108.01

Answer

ANSI A108.01 covers general requirements for the installation of ceramic tile and includes Section 4.3, which addresses movement joint requirements consistent with TCNA EJ171.

Question 2

Which installation condition most commonly requires movement joints to be spaced closer together than the standard 20–25 foot interior recommendation?

Accepted Answer

Radiant floor heating systems

Answer

Radiant floor heating causes repeated thermal cycling that significantly increases expansion and contraction stresses, requiring movement joints to be placed more frequently.

Question 3

A CTI inspector finds that a contractor has tiled and grouted directly over an existing movement joint, sealing it shut. How should this be documented?

Accepted Answer

As a deficiency requiring remediation to restore the joint function

Answer

Grouting over a movement joint eliminates its ability to relieve stress; this is a clear violation of TCNA EJ171 and must be documented as a deficiency requiring corrective action.

Question 4

Why do diagonal tile layouts typically require movement joints at reduced spacing compared to straight grid layouts?

Accepted Answer

Diagonal patterns create greater shear stress concentration and reduce the effective span between joints

Answer

In a diagonal layout, shear forces are transferred differently across the tile field, concentrating stress at fewer points and requiring closer movement joint spacing to prevent cracking.

Question 5

When inspecting a tile installation, which condition at a movement joint would indicate sealant failure requiring remediation?

Accepted Answer

Cohesive or adhesive splitting, cracking, or pull-away from tile edges

Answer

Cohesive splitting (tearing through the sealant) or adhesive failure (pull-away from tile edges) indicates the sealant has exceeded its elongation capacity and no longer provides movement relief.

CTI - Certified Tile Inspector Practice Test

CTI - Certified Tile Inspector Practice Test

CTI Movement Joints & Expansion Joints 3