CFI CFI Wood & Hardwood Flooring 2 — Questions and Answers
Question 1: What is the Janka hardness rating primarily used for in hardwood flooring selection?
- Measuring the plank's moisture resistance
- Indicating the force needed to embed a steel ball halfway into the wood (Correct answer)
- Grading the visual appearance of the wood grain
- Determining the plank's sanding capability
Correct answer: Indicating the force needed to embed a steel ball halfway into the wood
The Janka hardness test measures the resistance of wood to denting and wear by recording the force needed to embed a 0.444-inch steel ball halfway into the sample.
Question 2: Which of the following hardwood species has the HIGHEST Janka hardness rating among commonly used US flooring species?
- Red Oak
- Maple
- Brazilian Cherry (Jatoba) (Correct answer)
- White Oak
Correct answer: Brazilian Cherry (Jatoba)
Brazilian Cherry (Jatoba) has a Janka rating of approximately 2,350 lbf, making it significantly harder than domestic species like Red Oak (1,290 lbf).
Question 3: When installing hardwood flooring over a concrete slab, which installation method is generally NOT recommended?
- Glue-down engineered hardwood
- Floating engineered hardwood
- Nail-down solid hardwood directly to concrete (Correct answer)
- Glue-down solid hardwood (thinner profiles)
Correct answer: Nail-down solid hardwood directly to concrete
Nail-down solid hardwood directly to concrete is not recommended because concrete does not accept nails and the slab can retain moisture that damages solid wood.
Question 4: The term 'cupping' in hardwood flooring refers to:
- Planks that have buckled upward in the center
- Plank edges that are higher than the center, creating a concave surface (Correct answer)
- Gaps forming between planks during winter
- A finish application defect
Correct answer: Plank edges that are higher than the center, creating a concave surface
Cupping occurs when the edges of a hardwood plank are higher than the center, typically caused by excess moisture on the underside of the plank.
Question 5: What is the purpose of a moisture barrier or vapor retarder installed beneath a hardwood floor?
- To improve sound insulation between floors
- To slow the transfer of moisture vapor from the subfloor or slab into the hardwood (Correct answer)
- To act as a cushion during installation
- To prevent adhesive from bonding to the subfloor
Correct answer: To slow the transfer of moisture vapor from the subfloor or slab into the hardwood
A moisture barrier slows vapor transmission from the subfloor or slab, protecting the hardwood from moisture-induced swelling, cupping, or mold growth.
Question 6: Hardwood flooring planks should be racked (dry-laid) before installation primarily to:
- Allow the adhesive to cure
- Blend color and grain variation for a natural, aesthetically pleasing layout (Correct answer)
- Check subfloor levelness
- Pre-drill nail holes to avoid splitting
Correct answer: Blend color and grain variation for a natural, aesthetically pleasing layout
Racking hardwood planks before gluing or nailing them down allows the installer to blend color tones and grain patterns from different boxes for a natural appearance.
CFI CFI Wood & Hardwood Flooring 2
What is the Janka hardness rating primarily used for in hardwood flooring selection?