WLFI Inspection Procedures & Problem Diagnosis 3 — Questions and Answers
Question 1: An inspector observes that a wood floor has a consistent bow (high center, low edges) across multiple boards in the same run. This is called:
- Cupping
- Crowning (Correct answer)
- Checking
- Telegraphing
Correct answer: Crowning
Crowning occurs when the center of a board is higher than its edges, often caused by moisture on the surface or previous cupping that was sanded while still wet.
Question 2: What is the primary purpose of the acclimation period before installing solid hardwood flooring?
- To allow the finish to off-gas before installation
- To let the wood reach equilibrium moisture content with the installation environment (Correct answer)
- To check each board for grade defects
- To allow the subfloor adhesive to cure
Correct answer: To let the wood reach equilibrium moisture content with the installation environment
Acclimation allows the wood's moisture content to equalize with the ambient conditions in the room, minimizing post-installation movement.
Question 3: During a wood floor inspection, the inspector identifies a buckled area where boards have lifted several inches off the subfloor. The most likely cause is:
- Incorrect finish product used
- Insufficient fastener penetration depth
- Extreme moisture exposure with no room for expansion (Correct answer)
- Boards installed with grain running perpendicular to joists
Correct answer: Extreme moisture exposure with no room for expansion
Buckling occurs when flooring absorbs excessive moisture and expands with nowhere to go because expansion gaps are insufficient or obstructed.
Question 4: An inspector is evaluating a glue-down engineered wood floor. Which test best determines if the adhesive bond has failed?
- Scratch test along the grain direction
- Walk the floor and listen for hollow or drumming sounds (Correct answer)
- Measure the moisture content at multiple points
- Check subfloor levelness with a straightedge
Correct answer: Walk the floor and listen for hollow or drumming sounds
A hollow or drumming sound when walking or tapping indicates that the adhesive bond has failed and the board is no longer adhered to the substrate.
Question 5: A homeowner complains that their prefinished solid hardwood floor shows numerous small cracks along the length of individual boards. This defect is called:
- Checking (Correct answer)
- Compression set
- Telegraphing
- Wicking
Correct answer: Checking
Checking refers to surface cracks that develop along the grain of a wood board, typically caused by rapid or extreme drying.
Question 6: When inspecting laminate flooring, the inspector notices that joints between panels are peaking (raising at the seams). What is the most likely cause?
- The underlayment is too thick for the product specification
- Boards were installed without engaging the click-lock properly
- The subfloor has a low spot under the joint
- Too much moisture from below is causing the core to swell at the edges (Correct answer)
Correct answer: Too much moisture from below is causing the core to swell at the edges
Edge swelling from subsurface moisture causes the HDF core to expand, lifting the board edges at the seams and creating a peaked appearance.
Question 7: Which standard governs the acceptable flatness tolerances for a wood subfloor before hardwood flooring installation?
- ASTM F710
- NWFA Installation Guidelines (Correct answer)
- ANSI A108
- ICC IBC Section 1404
Correct answer: NWFA Installation Guidelines
The NWFA (National Wood Flooring Association) Installation Guidelines specify the acceptable subfloor flatness tolerances for wood flooring installations.
WLFI Inspection Procedures & Problem Diagnosis 3
An inspector observes that a wood floor has a consistent bow (high center, low edges) across multiple boards in the same run.
This is called: