CFI Flooring Materials & Installation Techniques 3 — Questions and Answers
Question 1: What is the primary purpose of a crack isolation membrane installed beneath ceramic tile?
- To increase tile bond strength
- To prevent cracks in the substrate from transferring to the tile (Correct answer)
- To waterproof the substrate
- To level an uneven subfloor
Correct answer: To prevent cracks in the substrate from transferring to the tile
A crack isolation membrane, such as KERDI or similar products, allows slight substrate movement without transmitting the crack through to the tile surface.
Question 2: Engineered hardwood differs from solid hardwood primarily in that engineered hardwood:
- Cannot be sanded or refinished
- Has a cross-ply core that improves dimensional stability (Correct answer)
- Is made entirely from synthetic materials
- Must always be floated and never glued
Correct answer: Has a cross-ply core that improves dimensional stability
Engineered hardwood uses a cross-ply plywood or HDF core that resists expansion and contraction better than solid wood, making it more dimensionally stable.
Question 3: The 'wet-set' method for installing mosaic tile means:
- Using a water-activated adhesive
- Setting tile into a freshly floated mortar bed before it cures (Correct answer)
- Grouting immediately after tile placement
- Pre-soaking tiles before installation
Correct answer: Setting tile into a freshly floated mortar bed before it cures
In the wet-set method, tiles are pressed into an uncured mortar bed, allowing them to bond as the mortar hardens around the tile.
Question 4: What is the recommended expansion gap around the perimeter when installing a floating hardwood floor in a 20×20 ft room?
- 1/16 inch
- 3/4 inch (Correct answer)
- 1/4 inch
- 1-1/2 inches
Correct answer: 3/4 inch
A 3/4-inch perimeter expansion gap is standard for floating hardwood to allow for seasonal wood movement, hidden by baseboard or quarter round.
Question 5: Which subfloor panel product is specifically engineered to resist moisture and is preferred as underlayment for ceramic tile in wet areas?
- Oriented strand board (OSB)
- Standard plywood
- Cement backer board (CBU) (Correct answer)
- Particleboard
Correct answer: Cement backer board (CBU)
Cement backer board (CBU) such as HardieBacker or Durock is moisture-resistant and provides a stable, non-organic substrate for tile in wet areas.
Question 6: When using the fold-and-pull seam technique for sheet vinyl, the adhesive is applied to:
- Both the floor and the sheet back simultaneously
- Half the floor at a time after folding the sheet back (Correct answer)
- The sheet only, not the floor
- The full floor before the sheet is unrolled
Correct answer: Half the floor at a time after folding the sheet back
The fold-and-pull method involves folding half the sheet back, spreading adhesive on the exposed subfloor, then laying the sheet into the adhesive before repeating on the other half.
Question 7: Which type of grout requires no sealing and resists staining without additives?
- Sanded cement grout
- Unsanded cement grout
- Epoxy grout (Correct answer)
- Latex-modified grout
Correct answer: Epoxy grout
Epoxy grout is non-porous and inherently stain- and chemical-resistant, so it does not require sealing after installation.
CFI Flooring Materials & Installation Techniques 3
What is the primary purpose of a crack isolation membrane installed beneath ceramic tile?