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### BCGCA3005B

Construct Ceiling Frames

Ceiling Frame is the structure between the top of walls and the roof

- Enclose the Room
- Frame Consists of Ceiling Joists, Ceiling Trimmers, Hangers, Hanging Beams
- Used in Skillion, Gable, Hip Roof

- Horizontal Members with ends rested on top wall plate
- Generally spaced at 450mm or 600mm
- Initially ceiling material will determine spacing
- Sizes and Grading are determined from Span Tables Ceiling Lining may be nailed directly to Joists

Provide Lateral Tie between opposing Rafters

Portal Frame Design

Walls Require Alternate Bracing

Butressing

Typical Residential Design

(Coupled Roof)

Installation of Ceiling Joists

Tops of Ceiling Joist may be trimmed so as not to protrude

- Ceiling Joists shall be spaced to support ceiling linings
- For Coupled Roofs
- Ceiling Joists run in same direction as rafters
- Be in single lengths or spliced
- Same spacing as Rafters

Ceiling are an Important Structure

- Support For Ceiling Linings
- Tie bases of Rafters (Stop Spreading)
- Straighten Walls (Between Intersecting Walls)
- Diaphragm Bracing (9000mm Max)

Joining Ceiling Joists

- Be only made at points of support
- Lapped over support 3 times depth- 6 hand driven nails 75mm x 3.8- 8 machine driven nails 75mm x 3.08- or 1 M12 Bolt
- Butt joined - fish plates to each side- minimum length - 6 x depth of joist- 19mm x Depth of Ceiling Joist
- Nailing plates as per manufacturers detail

Excercise

- Complete Question 6

Selecting Members

10mm Plasterboard Direct Fix

Single Span

Ceiling Joist A

x = 2000mm

F5 @ 450 c to c

What size Ceiling Joist is Required ?

Remember First Check the NOTES!

Check Grade !

From Appendix B

10mm Plaster Board = 7.5kg/sqm

Therefore OK

What are Ceiling Masses ?

Refer Appendix B – AS 1684.2

450 Centres

Next Highest Span above Required 2000mm Span

Selecting Members

Single Span

Ceiling Joist A

x = 2000mm

F5 @ 450 c to c

120mm x 35mm

Single Span

Ceiling Joist B

x = 2700mm

F7 @ 450 c to c.

What Size Ceiling

Joists are required?

Selecting Members

Continuous Spans

10mm Plasterboard Direct Fix

Single Span

Ceiling Joist B

x = 2500mm

F7 @ 450 c to c

120mm x 45mm

Ceiling Joist A & B – AS 1684 requires joists to be Continuous

x + y = 4500mm

F5 @ 450 c to c

Note – Maximum Span is 2700mm, 4700mm is irrelevant

Compare Single to Continuous

120 x 45 F7

120 x 35 F5

10mm Plasterboard Direct Fix

Ceiling Joist A & B as Continuous Joist

450 c to c,

10mm Plasterboard

120 x 35 F5 is Sufficient

Exercise

- Complete Question 5 on Workbook

Using MGP 10 select suitable Ceiling Joints

Joist X =

Joist Y =

Using MGP 10 select suitable Ceiling Joints for continuous span

Max Span Required

Ceiling Joist size =

120 x 35

140 x 35

3500

120 x 35

Framing Openings in Ceilings

- AS 1684.2 cl 7.2.4.4
- Openings up to 1000mm – same size as ceiling
- 1000mm up to 3000mm – width increased (accumulatively) by 20% for every 300mm of opening or part there of.

Ceiling Joists 90 x 45 MGP 10 Radiata Pine

1800 Square Opening

1800 – 1000 = 800 (1000mm being maximum allowable to use same members)

800mm divided by 300mm = 2.667 therefore 3 increments

45mm x 1.2 = 54mm 1st Increase by 20%

54mm x 1.2 = 65mm 2nd Increase by 20%

65mm x 1.2 = 78mm 3rd Increase by 20%

Therefore minimum size is 90mm x 78mm

Excercise

- Complete Questions 4 & 5 in the Worksheet

What items determine the sizing of Ceiling Joists?

Refer to Span Tables

Complete Questions 7 & 7.1 of Workbook

Hanging Beams- also referred to as Hangers

Hanging Beams provide support to Ceiling Joists where walls are available

Connecting Hanging Beams to Ceiling Joists

Ceiling Dog

Connecting Hanging Beams to Ceiling Joists

Triple Grips

4 @ 35mm x 3.15 Connector Nails in to each member

Hanging Beams shall be nailed or bolted to a rafter

Beam Shall Bear Full Width of Plate on Packing

Where more than 2/3 of the Beam needs to be trimmed a ceiling trimmer is required

Isometric View

Complete Exercise 8 of the Work Book

Hanging Beams

Gable Ends

Packing Full Width of Plate. Build up to top of Ceiling Joists

Where Beam is longer than 3000mm stud required directly below

Where this occurs at Gable Ends , no ceiling joists to brace end wall

The Beam will also act as a “Binder”

Binders refer AS 1684.2 cl 6.2.5.1

At Gable Ends walls do not have Ceiling Joists to Brace them

Work Book

Complete Question 9

Check Notes

Without Hanging Beam all Load is transferred to walls

Hanging Beam is similar to having a wall in same location

Counter Beamscalled Hanging Beams in the TAFE GUIDE

Reduce Span of Hanging Beam

At 90º to Hanging Beams

Supported on Walls

With stud directly below if longer than 3000mm

Trimmed for Roof Finishes

Similar to Hanging Beams

Intersection of Hanging & Counter

Note – Counter Beam is Supporting Hanging Beam

Intersection of Hanging & Counter

Hanging Beam

Counter Beam

Packer to Provide

Clearance to Ceiling

Complete Q11 & 11.1 in Workbook

Reduces Span of Hanging Beam

Without Counter Beam, Hanging Span is x

Load Flow

x/2

Once Counter Beam is installed, Hanging Beam Span is now x/2

x/2

Load Flow

Determine Suitable Counter Beam

Complete Questions 11 & 12

F8

MGP 12

F14

F27

190 x 45

170 x 35

175 x 40

140 x 45 or 2/120 x 35

Counter beam span 3600

Hanging Beam Length (x) 6000

Combined Strutting/Hanging Beams

Reduce Span of Ceiling Joists and Purlin

Supported on Walls

With stud directly below if longer than 3000mm

Roof Load Strutted down to Hanging Beam

Ceiling Load Width (CLW)

Sheet Roof

Ceiling Joist Span (x) = 4200

Hanging Beam Span = 6000

Rafter Span (B) = 4500

Therefore CLW = 2100

Remember what we are trying

Work out is what load is the

member carrying

Roof Area Support

Sheet Roof

Why A ?

Strut Down to Beam from Purlin(Roof)

Struts down to top plate distance between these 2 struts is A

Therefore strut takes load ½ way between other supports

5000/2 = A

A = 2500

Ceiling Joist Span (x) = 4200

Hanging Beam Span (A) = 5000

Rafter Span (B) = 4500

Why B?

Rafter is supported by Purlin

Rafter Load is Transferred thru

Purlin Strut

Ridge Strut,

Top Plate

Therefore Beam takes load ½ way between supports (4500/2)

= 2250

Ceiling Joist Span (x) = 4200

Hanging Beam Span (A) = 5000

Rafter Span (B) = 4500

Remember Ceiling Load Width = 2100

Next we need to calculate what roof load it is carrying?

2.250 (Rafter Span) x

2.500 ( HB Span)

=5.625

Required Hanging Beam Span = 5000

Required Hanging Beam Span = 5000mm

Combined Strutting/Counter Beams

Reduce Span of Hanging Beam

Supported on Walls

With stud directly below if longer than 3000mm

Roof Load Strutted down to Hanging Beam

Alternate Ceilings P288

Flat Roof Construction

Estimating

Determine Joist Layout

Estimating

Bay 1

Bay 2

Bay 1 = Joist 1 to Joist 9 = 9

Bay 2 = Joist 10 to 17 = 7

Determine No of Ceiling Joists

By Bay

Estimating

Bay 1

Bay 3

Bay 2

Bay 1 = Joist 1 to Joist 9 = 9

Bay 2 = Joist 10 to 17 = 7

Bay 3 = Joist 18 to 22 = 5

Determine No of Ceiling Joists

By Bay

Single Span greater than 2000mm

Ceiling Trimmers

6650 ÷ 600 = 11.083 = 12

+ 1 to Close = 13

+ 1 for intersection =14

3350 ÷ 600 = 5.6 = 6

+ 1 to Close = 7

Ceiling Trimmers

6650 ÷ 600 = 11.083 = 12

+ 1 to Close = 13

+ 1 for intersection =14

800 ÷ 600 = 1.3 = 2

+ 1 to Close = 3

3350 ÷ 600 = 5.6 = 6

+ 1 to Close = 7

Ceiling Trimmers

Answer

23 @ 0.600 = 13.800

Note as blocks no need to specify length

6650 ÷ 600 = 11.083 = 12

+ 1 to Close = 13

+ 1 for intersection =14

800 ÷ 600 = 1.3 = 2

+ 1 to Close = 3

3350 ÷ 600 = 5.6 = 6

+ 1 to Close = 7

1 @ 3.400

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