Presentation is loading. Please wait.

Presentation is loading. Please wait.

Construct Pitched Roofs (Simple)

Similar presentations


Presentation on theme: "Construct Pitched Roofs (Simple)"— Presentation transcript:

1 Construct Pitched Roofs (Simple)
BCGA3007B Construct Pitched Roofs (Simple)

2 Types of Roofs we will Cover
Coupled Roofs Gable Roofs

3 Types of Roofs we will Cover
Non Coupled Roofs Skillion Roofs Lean to Graded Battens

4 What is a Roof

5 Roof Structure Definitions

6 Roof Structure Definitions

7 Flat Roofing Pitch less than 1:11.5 or 5⁰
Ceilings usually directly fixed to underside. Member Sizes Adjusted Accordingly Usually Single Span, therefore large members Due to low pitch roof coverings types are limited

8 Skillion Roofs Freestanding Wall at one end is higher
Walls parallel to rafters are tapered

9 Selecting Members What determines rafter spacing ?
Ceiling Linings – if direct fixing Roof Batten Span Required Rafter span Roof Material Mass Ceiling Mass – if direct fixing

10 Selecting Members

11 For types of roof we will cover today

12 Roof Battens Have Span Limits – it is not uncommon where ceilings are unlined to space rafters greater than 650 c to c. Note 70 x 35 will be unsuitable Always Check Notes first to ensure it is suitable

13 Select Rafter Size Pitch 3° Rafters 600 c to c
Step 1 – Calculate Rafter Length i.e. Distance Between Supports Note Horizontal Distance is called run Span = 4200 / cosine 3° = 4200/ = 4206

14 190 x 45 with maximum overhang of 1550
Rafter Spacing Read Notes Roof Load

15 Alternate Method to Calculate Rafter
Rise 1 in 20 Rafters 600 c to c 230 Rise = Every 20 meters, Rise of 1 meters Rise per m = 1/20 = 0.05 x 4.6 Rise = 0.230 Use Pythagoras to Calculate Rafter Length Rafter = √ ( ) = 4.606 To Determine Pitch Pitch =230/ 4600 = 0.05 = Inv Tan 0.05 = 2.862°

16 Complete Following

17 Answers

18

19 Alternative Set Out Length = 4606mm 230
Step 1 – Set out Rafter Length along one edge Remember to allow for overhang Step 2 – Extend Plumb Lines to other edge

20 Similar Triangles If all angles are the same the triangles are similar
All sides are increased by same magnitude

21 Similar Triangles

22 Basic Steel Square Demo
Roof Run = 4600 Roof Rise = 210 Ratio =210/4200 = 0.05 Square Run = 500mm Rise = 500 x 0.05 = 25 Alternate Method – Using Similar Triangles Roof Pitch = 3° Tan 3⁰ x 1m =0.052m (Answer is always value for 1) Remember angles stay the same in similar triangles Rise for triangle half size = = tan 3⁰ x 0.500m = 0.026m or 26mm Plumb Cut 3⁰ 1

23

24

25

26 Graded Batten Roof Where direct fix ceiling is required to be level on flat roof Fall is achieved with Battens

27 Constructing a Skillion Roof
Place End Rafters, allowing for soldier trims

28 Place Rafters at maximum 600 centres (580)
Provide Solid Blocking at 1800 centers max

29 Install Soldier Trims

30 Cut Overhangs & Install Verge Trims

31 Install Wall Blocking

32 Install Fascia

33 Kliplock Minimum Pitch 1⁰

34 Trimdeck Minimum Pitch 2⁰

35 Custom Orb Generally Known as Corrugated Iron
Minimum Pitch 5⁰ Not Suitable For Flat Roofs Maximum Recommended Support Spacings Type of Span Thickness (mm) BMT 0.42 0.48 Roofs Single Span End Span Internal Span Unstiffened Eaves Overhang Stiffened Eaves Overhang Walls Single Span End Span Internal Span Overhang


Download ppt "Construct Pitched Roofs (Simple)"

Similar presentations


Ads by Google