Chapter 29 Quiz: Flooring Systems

Multiple Choice

1. The maximum allowable variation in subfloor flatness for a ceramic tile installation is:

a) 3/16 inch in 10 feet b) 1/4 inch in 10 feet c) 1/8 inch in 10 feet (and 1/16 inch in 24 inches) d) 1/2 inch in 10 feet, provided the high spots are feathered

2. The primary disadvantage of OSB compared to plywood as a subfloor material in moisture-prone areas is:

a) OSB is not rated for structural subfloor applications b) OSB is more expensive than plywood and the cost difference isn't justified c) OSB is susceptible to edge swelling when repeatedly wet and dried, which telegraphs through finish flooring d) OSB cannot be fastened to floor joists with screws — only nails are appropriate

3. Solid hardwood flooring cannot be installed below grade primarily because:

a) Building codes prohibit wood flooring in basements due to egress requirements b) The moisture exposure below grade is too variable and would cause expansion, buckling, or excessive shrinkage c) Nail-down installation cannot be performed on concrete slabs d) Solid hardwood does not hold fasteners well at low temperatures typical of basements

4. The most important quality specification to compare when purchasing luxury vinyl plank is:

a) Total plank thickness b) Core type (SPC vs. WPC) c) Wear layer thickness in mil d) Whether underlayment is attached

5. A homeowner installs LVP throughout a vacation home that is unheated in winter, where temperatures may drop to 30°F, and then heated to 72°F for summer use. The most likely failure mode is:

a) The photographic layer fades under UV exposure when the home is closed up b) The click-lock joints crack at low temperature due to brittleness c) The floor buckles during the heating season because expansion gaps were insufficient for the temperature range d) Condensation forms between the LVP and concrete slab during humid summer months

6. What is the L/360 deflection standard for tile installation, and why does it matter?

a) It means the floor must not flex more than 1/360 of its span — tile cracks when the substrate flexes because tile is rigid and brittle b) It means the tile must be laid within 1/360 of level — a tolerance for out-of-plumb c) It is a fire rating standard for tile in kitchens d) It specifies that tile grout joints must be at least 1/360 of an inch wide

7. A floor squeak occurs at a single specific point and is worse when walking toward the south. From the basement, a helper confirms that the subfloor moves slightly at that point when weight is applied. The most likely cause is:

a) Hardwood planks rubbing against each other edge-to-edge b) A gap between the subfloor panel and the joist, causing the subfloor to flex under load c) A hot water supply pipe rubbing against a joist penetration d) The finish floor has delaminated from the subfloor due to adhesive failure

8. Which carpet fiber type is most appropriate for a high-traffic hallway where durability and resistance to matting are the primary concerns?

a) Olefin (polypropylene) b) Polyester (PET) c) Nylon d) Wool

9. The purpose of a "T-molding" transition strip between two adjacent rooms is:

a) To bridge a height difference between two floor surfaces of different thickness b) To cover the expansion gap between two floors of approximately equal height c) To protect the exposed edge of hardwood at a step-down or stair landing d) To seal the gap between a sliding door track and the floor

10. When installing a floating floor (LVP or engineered hardwood), the baseboard must:

a) Be fastened through the finish floor into the subfloor for stability b) Be installed before the floor, with the floor cut to fit snugly under it c) Be fastened only to the wall framing, so the floor can expand freely beneath it d) Have a 1/8-inch gap between baseboard and floor, sealed with flexible caulk

Short Answer

11. Explain why the subfloor preparation step is more important to the success of a tile floor than the quality of the tile itself.

12. What is the difference between solid hardwood and engineered hardwood in terms of structure, moisture performance, and refinishing capability? For which applications is each most appropriate?

13. Describe two specific situations where LVP performs worse than hardwood, despite being generally considered more durable in most residential applications.

14. A carpet installer is about to lay new carpet and asks you to confirm the pad selection. The homeowner wants to save money on the pad and is considering a 1/4-inch thin pad. What advice would you give, and why?

15. You hear a squeak in the floor that correlates with hot water use (louder in the morning when showers are running) rather than foot traffic. What is the most likely cause, and what is the appropriate investigation step?

Answer Key

Multiple Choice: 1-c, 2-c, 3-b, 4-c, 5-c, 6-a, 7-b, 8-c, 9-b, 10-c

Short Answer Guidance:

11. Tile is a rigid, brittle material that cracks when the substrate beneath it flexes. Even excellent tile — dense, well-made, properly spaced — will crack if the subfloor isn't stiff enough (L/360 deflection limit) or flat enough (1/8 inch in 10 feet). The thinset bond can also fail if the substrate moves relative to the tile layer. A failed tile installation typically can't be repaired incrementally — it requires tile removal (often damaging the tile in the process), substrate correction, and reinstallation. By contrast, a good subfloor preparation job is a one-time investment that protects the floor for decades. Spending $200–$500 on subfloor prep to protect a $3,000 tile installation is straightforward economics.

12. Solid hardwood is milled from a single piece of wood, 3/4-inch thick, and expands and contracts significantly with humidity changes. It can be refinished 5+ times over its lifetime (removing roughly 1/16 inch per refinish from the top). It cannot be installed below grade due to moisture variability. Engineered hardwood has a cross-laminated core with a real wood wear layer (typically 2–6mm thick), making it dimensionally stable across humidity swings. It can be installed on-grade and in some below-grade applications. The number of possible refinishing cycles is limited by wear layer thickness — a 2mm wear layer allows one or two refinishes; a 6mm layer allows four or more. Solid hardwood is preferred for above-grade traditional installations where maximum refinishing life is desired. Engineered hardwood is preferred for below-grade, on-grade, and radiant heat applications.

13. Two LVP limitations: (1) Temperature expansion: LVP expands and contracts significantly with temperature changes. In spaces with extreme temperature swings — unheated vacation homes, south-facing sunrooms, or spaces over radiant heat without proper gap management — LVP can buckle if expansion gaps are inadequate. Hardwood responds to humidity more slowly and is more manageable in many mixed-temperature environments. (2) Cannot be refinished: Once the wear layer is worn through, the floor must be replaced. Well-maintained hardwood can be refinished repeatedly for a century or more. For a homeowner planning a 30+ year stay in a home, the long-term total cost of LVP may exceed hardwood when replacement is factored in.

14. Advise against the thin pad. The pad's quality is as important as the carpet quality in determining comfort and longevity. A thin, low-density pad provides insufficient support to the carpet backing, causing it to flex with every step and accelerating breakdown of the backing material. The carpet will mat and degrade significantly faster than its rated lifespan — potentially 30–50% faster. The cost difference between adequate pad (7/16-inch, 6 lb density) and thin pad is typically $0.30–$0.60/sq ft in materials — for a 200 sq ft bedroom, a $60–$120 investment difference. The performance and carpet-life impact is far larger than this cost difference justifies. Additionally, thick pad significantly improves the feel and comfort of the carpet underfoot — which is the primary reason to have carpet in a bedroom in the first place.

15. A squeak that correlates with hot water use rather than foot traffic is almost certainly a plumbing pipe rubbing against framing. Hot water pipes expand when water runs through them — a copper 3/4-inch supply pipe running 20 feet expands approximately 1/4 inch over a 100°F temperature rise. If this pipe passes through a framing hole that fits snugly, the pipe rubs as it expands. The appropriate investigation: locate where the hot water supply pipes run (typically visible in the basement or crawlspace) and identify any location where a pipe passes through framing. The fix: enlarge the hole slightly to give the pipe clearance, or insert a foam insulator sleeve around the pipe at the framing contact point to cushion the movement.