CTI Movement Joints & Expansion Joints 1 — Questions and Answers
Question 1: Which TCNA specification number specifically covers movement joint requirements in tile installations?
- EJ141
- EJ171 (Correct answer)
- EJ201
- EJ251
Correct answer: EJ171
TCNA EJ171 is the industry-standard specification that defines movement joint requirements, placement, and materials for tile installations.
Question 2: What is the minimum recommended width for movement joints in tile installations per TCNA EJ171?
- 1/8 inch
- 1/4 inch (Correct answer)
- 3/8 inch
- 1/2 inch
Correct answer: 1/4 inch
TCNA EJ171 specifies a minimum movement joint width of 1/4 inch to allow adequate sealant performance and accommodate thermal movement.
Question 3: For interior tile installations, what is the maximum recommended spacing between movement joints per TCNA EJ171?
- 8–12 feet in each direction
- 16–18 feet in each direction
- 20–25 feet in each direction (Correct answer)
- 30–35 feet in each direction
Correct answer: 20–25 feet in each direction
TCNA EJ171 recommends movement joints at maximum 20–25 feet in each direction for interior tile installations to relieve built-up stresses.
Question 4: Movement joints must be installed wherever tile abuts which type of surfaces?
- Only exterior masonry walls
- Restraining surfaces such as walls, curbs, columns, pipes, and changes in plane (Correct answer)
- Only plumbing fixtures and drains
- Perimeter walls in commercial projects only
Correct answer: Restraining surfaces such as walls, curbs, columns, pipes, and changes in plane
Per TCNA EJ171, movement joints are required wherever tile meets any restraining surface — walls, curbs, columns, pipes, or changes in plane — to prevent stress concentration.
Question 5: What type of sealant is recommended for movement joints in wet or exterior tile areas?
- Sanded Portland cement grout
- Silicone or polyurethane sealant (Correct answer)
- Epoxy grout
- Latex-modified unsanded grout
Correct answer: Silicone or polyurethane sealant
Silicone or polyurethane sealants are flexible, waterproof, and bond to tile edges, making them the correct choice for movement joints especially in wet or exterior conditions.
Question 6: What is the most likely consequence when movement joints are entirely omitted from a large tile installation?
- Grout lines become darker over time
- Cracking, delamination, or tile lifting due to unrelieved thermal and structural movement (Correct answer)
- Faster moisture absorption through the tile surface
- Accelerated efflorescence in grout joints
Correct answer: Cracking, delamination, or tile lifting due to unrelieved thermal and structural movement
Without movement joints, stress from thermal expansion, moisture, and structural deflection has no relief path, causing the tile or mortar bond to crack, debond, or tent.
Question 7: Movement joints located over structural building expansion joints should be:
- Narrower than the structural joint to save space
- The same width as or wider than the underlying structural joint (Correct answer)
- Filled with rigid epoxy grout for stability
- Omitted when the tile bond is strong enough
Correct answer: The same width as or wider than the underlying structural joint
The tile movement joint must be at least as wide as the structural joint beneath it so the full range of building movement is accommodated without transferring stress into the tile.
CTI Movement Joints & Expansion Joints 1
Which TCNA specification number specifically covers movement joint requirements in tile installations?