CLC CLC Structural Carpentry & Framing 1 — Questions and Answers
Question 1: What is the standard spacing for wall studs in residential construction?
- 12 inches on center
- 16 inches on center (Correct answer)
- 24 inches on center
- 32 inches on center
Correct answer: 16 inches on center
Residential wall studs are typically spaced 16 inches on center, though 24-inch spacing is also code-compliant in some applications.
Question 2: Which type of header is most commonly used above a load-bearing door opening?
- Single 2×4 flat
- Double 2×10 with 1/2-inch plywood spacer (Correct answer)
- Single 2×6 on edge
- Triple 2×4 stacked
Correct answer: Double 2×10 with 1/2-inch plywood spacer
A doubled 2×10 with a 1/2-inch plywood spacer is a common load-bearing header because it matches the wall thickness and provides adequate structural support.
Question 3: What is the purpose of a cripple stud in wall framing?
- To support the ridge board
- To fill the space above or below a rough opening (Correct answer)
- To transfer lateral loads to the foundation
- To connect parallel walls
Correct answer: To fill the space above or below a rough opening
Cripple studs are short studs placed above headers or below sills to maintain standard stud spacing and provide nailing surfaces.
Question 4: In platform framing, the subfloor acts as a working platform for:
- Roof truss assembly only
- Framing the next level's walls (Correct answer)
- Installing mechanical systems
- Pouring the concrete slab
Correct answer: Framing the next level's walls
Platform framing gets its name because each floor's subfloor serves as a platform on which the next level's walls are framed and raised.
Question 5: What is the minimum bearing length for a floor joist resting on a wood sill plate?
- 1 inch
- 1.5 inches
- 2 inches (Correct answer)
- 3 inches
Correct answer: 2 inches
IRC and most building codes require floor joists to bear a minimum of 1.5 inches on wood and 3 inches on masonry, but 1.5 inches is the wood minimum per IRC R502.6.
Question 6: Which framing member runs perpendicular to floor joists to prevent rotation and increase rigidity?
- Rim joist
- Ledger board
- Bridging or blocking (Correct answer)
- Beam pocket
Correct answer: Bridging or blocking
Bridging (either solid blocking or cross-bridging) is installed perpendicular to joists to resist rotation and distribute loads across multiple members.
CLC CLC Structural Carpentry & Framing 1
What is the standard spacing for wall studs in residential construction?