403A Floor, Wall & Roof Framing

Question 1

According to the National Building Code of Canada, what is the maximum allowable span for 38×184 mm (2×8) spruce-pine-fir floor joists at 400 mm O.C. spacing in a residential application?

Accepted Answer

Approximately 3.6 m

Answer

Approximately 4.5 m

Answer

Approximately 2.8 m

Answer

Approximately 5.2 m

Question 2

What is the purpose of blocking installed between floor joists at the bearing wall?

Accepted Answer

To prevent joist rotation and transfer loads to the bearing wall

Answer

To provide nailing for subfloor edges

Answer

To create a fire stop between floors

Answer

To support the rim joist

Question 3

When framing a load-bearing wall, what is the minimum number of jack studs (trimmer studs) required on each side of a door opening wider than 1 800 mm?

Accepted Answer

Two jack studs on each side

Answer

One jack stud on each side

Answer

Three jack studs on each side

Answer

No jack studs — king studs carry the load

Question 4

What is the purpose of a let-in brace in wood frame wall construction?

Accepted Answer

To provide racking resistance (lateral load resistance) in the wall

Answer

To support the top plate during framing

Answer

To carry vertical loads from roof to foundation

Answer

To create a nailing surface for exterior sheathing

Question 5

What does 'crown up' mean when installing floor joists?

Accepted Answer

Install the joist with the natural bow facing upward so floor loads will straighten it

Answer

Install the joist with the crown (label) side facing up

Answer

Use the joist with the largest cross-section facing upward

Answer

Orient the joist so the growth rings face up

Question 6

When doubling a top plate in wall framing, how must the lap joints be positioned?

Accepted Answer

Joints in the upper plate must be offset a minimum of 1200 mm from joints in the lower plate

Answer

Joints must align directly over each other for maximum strength

Answer

Joints must occur over a stud location only

Answer

Joints may be anywhere as long as nailing is adequate