WLFI Inspection Procedures & Problem Diagnosis 2 — Questions and Answers
Question 1: During a wood floor inspection, you notice cupping on boards near an exterior wall. What is the most likely cause?
- Excessive surface finish buildup
- Moisture infiltrating from the exterior or crawl space below (Correct answer)
- Improper nailing pattern during installation
- Boards cut too short at the wall
Correct answer: Moisture infiltrating from the exterior or crawl space below
Cupping near exterior walls typically indicates moisture intrusion from the outside environment or a wet crawl space beneath the floor.
Question 2: An inspector finds laminate flooring with edge swelling along the perimeter of a room. Which condition is most likely responsible?
- Insufficient expansion gap at the walls (Correct answer)
- Too many AC cores in the board construction
- Excessive adhesive squeeze-out
- Improper underlayment thickness
Correct answer: Insufficient expansion gap at the walls
Edge swelling at the perimeter indicates the flooring had no room to expand and is pressing against the wall, causing the edges to lift.
Question 3: Which tool is most appropriate for measuring the moisture content of a concrete subfloor before installing hardwood?
- Pin-type wood moisture meter
- Relative humidity test (in-situ probe) (Correct answer)
- Infrared thermometer
- Slope level gauge
Correct answer: Relative humidity test (in-situ probe)
In-situ relative humidity testing per ASTM F2170 is the industry-standard method for measuring moisture in concrete subfloors.
Question 4: A homeowner reports that their solid hardwood floor squeaks only in winter. What is the MOST probable cause?
- Improper stain application
- Seasonal shrinkage creating gaps where boards rub on fasteners (Correct answer)
- Too much adhesive was used during installation
- The finish coat is delaminating
Correct answer: Seasonal shrinkage creating gaps where boards rub on fasteners
In dry winter conditions, wood shrinks and boards can move against nails or adjacent boards, producing squeaks.
Question 5: When inspecting a laminate floor installation over radiant heat, an inspector should primarily verify that the:
- Surface finish meets wear-layer ASTM standards
- Manufacturer's maximum floor temperature specification was not exceeded (Correct answer)
- Underlayment is a minimum 6mm thickness
- T-molding was used at all doorways
Correct answer: Manufacturer's maximum floor temperature specification was not exceeded
Excess radiant heat can warp, delaminate, or buckle laminate flooring, so the manufacturer's maximum temperature limit is the critical compliance check.
Question 6: Which defect would be classified as a manufacturer defect rather than an installation defect?
- Boards not acclimated before installation
- Hollow-sounding areas due to uneven subfloor
- End-joint telegraphing through a thin wear layer (Correct answer)
- Missing expansion gap at a wall
Correct answer: End-joint telegraphing through a thin wear layer
A wear layer that is too thin to hide end-joint telegraphing is a product quality issue, not something the installer controls.
Question 7: During an inspection, gapping between laminate boards is observed throughout the field. The gap closes in summer and opens in winter. This pattern indicates:
- Improper click-lock engagement during installation
- Normal seasonal movement within acceptable range (Correct answer)
- A vapor barrier was omitted below the underlayment
- The subfloor was not flat to within 3/16 inch over 10 feet
Correct answer: Normal seasonal movement within acceptable range
Seasonal gapping that closes in humid summer months and opens in dry winter months reflects normal hygroscopic response within acceptable tolerances.
WLFI Inspection Procedures & Problem Diagnosis 2
During a wood floor inspection, you notice cupping on boards near an exterior wall.
What is the most likely cause?