403A Framing — Questions and Answers
Question 1: What is the standard spacing for wall studs in residential framing according to the National Building Code of Canada?
- 12 inches on centre
- 16 inches on centre (Correct answer)
- 24 inches on centre
- 32 inches on centre
Correct answer: 16 inches on centre
The NBC of Canada specifies 16 inches (406 mm) on centre as the standard spacing for wall studs in residential construction, providing adequate structural support for typical loads.
Question 2: When framing a load-bearing wall, what is the purpose of a double top plate?
- To increase the wall height
- To distribute loads across studs and tie intersecting walls together (Correct answer)
- To provide a nailing surface for drywall
- To act as a fire stop
Correct answer: To distribute loads across studs and tie intersecting walls together
A double top plate distributes vertical loads from above across the studs below and ties intersecting walls together by overlapping at corners and intersections, creating a unified structural system.
Question 3: What is a cripple stud in wall framing?
- A stud that runs the full height of the wall
- A short stud installed above or below a window or door opening (Correct answer)
- A diagonal brace used in exterior walls
- A temporary support stud used during construction
Correct answer: A short stud installed above or below a window or door opening
Cripple studs are short framing members installed above headers or below window sills to maintain stud spacing and transfer loads from the top plate to the header or from the sill to the bottom plate.
Question 4: In platform framing, what does each storey's floor rest on?
- Continuous studs running from foundation to roof
- The top plate of the wall below (Correct answer)
- Steel beams embedded in the walls
- Cantilevered joists from the foundation
Correct answer: The top plate of the wall below
In platform framing (the most common method in Canadian residential construction), each floor is built on top of the wall framing below, creating a platform for the next storey's walls to be erected upon.
Question 5: What is the minimum bearing length for a floor joist resting on a wood sill plate in Canadian construction?
- 19 mm (3/4 in.)
- 38 mm (1-1/2 in.) (Correct answer)
- 64 mm (2-1/2 in.)
- 89 mm (3-1/2 in.)
Correct answer: 38 mm (1-1/2 in.)
The NBC requires a minimum bearing length of 38 mm (1-1/2 inches) for floor joists resting on a wood sill plate, ensuring adequate load transfer to the foundation wall.
Question 6: When framing a corner, what is the purpose of using corner assemblies with extra studs or drywall clips?
- To increase fire resistance of the corner
- To provide a nailing surface for interior finish and improve insulation (Correct answer)
- To strengthen the corner against seismic forces
- To allow for electrical wiring passage
Correct answer: To provide a nailing surface for interior finish and improve insulation
Corner assemblies provide nailing surfaces for interior drywall and other finishes at inside corners. Modern energy-efficient designs use fewer studs with drywall clips to reduce thermal bridging.
403A Framing
What is the standard spacing for wall studs in residential framing according to the National Building Code of Canada?