CFI Wood & Hardwood Flooring Flashcards

What is the Janka hardness rating primarily used for in hardwood flooring selection?

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.

Which of the following hardwood species has the HIGHEST Janka hardness rating among commonly used US flooring species?

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).

When installing hardwood flooring over a concrete slab, which installation method is generally NOT recommended?

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.

The term 'cupping' in hardwood flooring refers to:

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.

What is the purpose of a moisture barrier or vapor retarder installed beneath a hardwood floor?

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.

Hardwood flooring planks should be racked (dry-laid) before installation primarily to:

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.