020202c Ceiling Framing

Question 1

What is the main purpose of ceiling joists?

Answer 1

Join the exterior walls together.

Question 2

How should ceiling joists be fastened to the wall plates?

Answer 2

Toe nailed to the wall plate with two 82 mm (3’1-1/4”) long nails.

Question 3

Identify 3 ways in which ceiling joists can meet on top of an interior bearing wall.

Answer 3

1. Butted and cleated together.
2. Lapped.
3. Lapped with blocking between them that is the same thickness as the rafters.

Question 4

How is joist layout affected when joists are lapped over an interior wall?

Answer 4

The layout on one exterior wall will be offset by the thickness of the ceiling joists.

Question 5

What must be done to the outside ends of ceiling joists?

Answer 5

The joists need an angled cut that matches the roof slope.

Question 6

What are stub joists?

Answer 6

Short joists that run 90 degrees to the regular joists. They are needed on lower sloped hip roofs to ensure that the hip rafters and ceiling joists do not interfere with each other.

Question 7

The minimum size of an attic access in a single family home?

Answer 7

500 mm

Question 8

What must be done to the joists if an opening in the ceiling is wider than two joists spacings?

Answer 8

The joists must be doubled on either side of the opening.

Question 9

Where would a flush beam be required?

Answer 9

An area in which no interior bearing wall is available to support the ceiling joists and the width of the building exceeds the maximum allowable span on the joists.

Question 10

What is a strongback?

Answer 10

An L-shaped framing member that is fastened to the tops of the ceiling joists. It stiffens the joists, reduces deflection and maintains the proper on-centre spacing.

Question 11

No header is required at the outside ends of the ceiling joists. T or F

Answer 11

T

Question 12

Ceiling framing takes place before all the walls have been erected, straightened, and braced. T or F

Answer 12

F. Only once all walls are erected, straightened and braced.

Question 13

What are the two primary structural purposes of ceiling framing?

Answer 13

To tie the exterior walls together and to help resist the outward pressure exerted by the roof rafters. The ceiling frame also carries the dead load of the attic insulation and ceiling finish material, such as drywall.

Question 14

Typically, ceiling joists run in the opposite direction as the roof rafters. T or F

Answer 14

F. The typically run in the same direction. This makes for a stronger building.

Question 15

Why is it preferable to have the rafters fall directly on a stud?

Answer 15

This provides direct transference of roof loads. The ceiling joists are placed beside the rafters.

Question 16

Should the angled cut of the ceiling joist be approximately 10 mm (3/8”) below the top edge of the rafter. T or F

Answer 16

T. If the rafter shrinks this provides clearance between the roof sheathing and the ceiling joist.

Question 17

Why would some builders prefer to leave the outside ends of the joist square?

Answer 17

This allows for thicker insulation directly over the exterior wall plates. The thicker insulation helps reduce heat loss at that location. A plate must be nailed to the tops of the joists to allow the rafters to be fastened.

Question 18

How are joists fastened to flush beams?

Answer 18

Joists are butted into the side of the beam. This keeps the bottoms of all the joists at the same elevation and provides a flush ceiling.

Question 19

Describe ribbons as they relate to ceiling joists.

Answer 19

Ribbons are lengths of 1x4 lumber nailed to the top of each ceiling joist. They run at 90 degrees to the joists and are normally placed at mid-span. They keep the joists at the required on-centre spacing and prevent the tops of the joists from twisting.

Question 20

When ceiling joists support roof loads, the depth of the joists must be at least __ mm greater than joists that do not support roof loads.

Answer 20

25 mm (1”)