Construct Ceiling Frames BCGCA3005B Construct Ceiling Frames

Intoduction

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

Ceiling Joists 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

Ceiling Joists Provide Lateral Tie between opposing Rafters Portal Frame Design Walls Require Alternate Bracing Butressing Typical Residential Design (Coupled Roof)

Definition – Coupled Roof

Non Coupled Roof

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

AS 1684.2 Ceiling Joists 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

Ceilings Provide Diaphragm Bracing

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 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! From Appendix B Refer p99 AS1684.2 Remember First Check the NOTES! From Appendix B 10mm Plaster Board = 7.5kg/sqm Therefore OK Check Grade ! 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?

Next Largest span after 2700mm Check for Required Grade ! 450 c to c

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

Next Largest span after 2700mm 450 c to c Continuous Span Check For Required Grade !

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 120 x 35 140 x 35 3500 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

Why Continuous Spans

Continuous Span

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 by 20% for every 300mm of opening

Ceiling Openings Example 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 Unitie 4 Timber Connector Nails in Each Member

Connecting Hanging Beams to Ceiling Joists Triple Grips 4 @ 35mm x 3.15 Connector Nails in to each member

End Support of Hanging Beams Hanging Beams shall 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

Restraining Deep Hanging Beams What is a Deep Beam ? Where depth is Greater than 7 times the Width

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

Selecting Member Sizes Hanging Beam Refer Question 10 Ceiling Joist Span = 3600mm Hanging Span = 4500mm

What is Ceiling Load Width ? Check Notes

Without Hanging Beam all Load is transferred to walls Hanging Beam is similar to having a wall in same location

Required Beam 190 x 45 MGP 10 What is Ceiling Load Width ? 1800mm What is the Hanging Beam Span ? 4500mm

Complete Workbook Q10

Counter Beams called 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

Intersection of Hanging & Counter Hanging Beam Counter Beam Packer to Provide Clearance to Ceiling Complete Q11 & 11.1 in Workbook

Counter Beams 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

Selecting Member Counter Beam Span = 3600mm Hanging Beam Length (x) = 6000mm

Counter Beam Spacing = x/2 There may be more than 1 X= 8000mm Beam Span 4000mm Check Grade Check Notes

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

Check Grade First we need to determine what ceiling load it carrying? Roof Masses Check Notes

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

Next we need to calculate what roof load it is 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

Roof Area Support 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

Strutting Beam No Ceiling Support Load Flow

Complete Q13

Alternate Ceilings P288 Flat Roof Construction

Exposed Grid Ceilings Page 289

Exposed Grid Ceiling

Concealed Fixed Suspended Ceiling Page 290

Direct Fix Systems Page 290

Estimating Determine No of Ceiling Joists 12 250/ 600 = 20.4167 12 250/ 600 = 20.4167 = 21 + 1 = 22 @6900

Place Hanging & Counter Beams Single Span greater than 200mm

Ceiling Trimmers 6650 ÷ 600 = 11.083 = 12 + 1 to Close = 13 800 ÷ 600 = 1.3 = 2 + 1 to Close = 3 13 + 3 + 7 +16 = 23 39 x 0.550 = 21.45 = 21.6 Say 3 @ 6.0 = 18.0 1 @ 3.6 = 3.6 6650 ÷ 600 = 11.083 = 12 + 1 to Close = 13x2 = 26 3350 ÷ 600 = 5.6 = 6 + 1 to Close = 7

Determine Hanging Beams 3 @ 5450 2 @ 2850 1 @ 3850 1 @ 3300 1 @ 4400

Counter Beam 1 @ 3.400

Ceiling Dogs Every Time a joist crosses a beam One at every Hanging Beam Two at Ceiling Joist Joints

Planning