Presentation is loading. Please wait.

Presentation is loading. Please wait.

Gable Roof BCGCA3007B.

Similar presentations


Presentation on theme: "Gable Roof BCGCA3007B."— Presentation transcript:

1 Gable Roof BCGCA3007B

2 Gable Roof Flush with no eaves Flush with raked eaves Boxed

3 Flush Gable (No Eaves) Rafter finishes in line with end wall
Barge fixed to outside wall No Overhang Studwork to take sheeting or support brickwork Not required to support roof

4 Flush Gable with Raked Eaves
Ridge Extends to Form Eave Verge Trimmers to Support Gable Rafter Trimmers to Support Verge Trims and Roof Battens Gable Stud supports Second Rafter Brick Work or Wall Lining Second Rafter to Support Verge Trims Roof Extends to Form eave Top Plate may be extended to support Rafter

5 Boxed Gable Verge Rafter Gable Studs & Sheeting
Purlin & Lintel Extended to Support Verge Rafter Minimum Back span 2 x Overhang Design 3 x Overhang Base of Gable Lined & Level with U/S of Eaves

6 Verges Is the Junction of the Roof and the Barge/Verge Board
Verge Detail for Tiled Roof

7 Verge Detail for Tiled Roof

8 Principles of Roofing Ridges are Level Rafters run at 90
Hips & Valleys bisect all internal & external Corners Roof members are set out along centerlines

9 Roofing Members Ridge Common Rafter Collar Tie Top Plate Hanging Beam
Purlin Top Plate Strutting Beam Strut Ceiling Joist Strut

10 Roof Members Common Rafter – Main Sloping Roof Member
Spacing 450mm or 600mm for Tiled Roofs 900mm for tiled roofs Supports Roof Battens which in turn support roof coverings Must be in single lengths or joined over supports Fixings 2 x 75mm Skew & 2 x 75mm into Ceiling Joist (if joist is > 38, 90mm Nails)

11 Roofing Members Ridge Common Rafter Collar Tie Top Plate Hanging Beam
Purlin Top Plate Strutting Beam Strut Ceiling Joist Strut

12 Ridge Highest Part of the Roof Will run full length of Gable Roof
Runs Parallel to TOP PLATE Fixes Rafters at Top of Roof Rafters are nailed either side and not offset by more than 1 thickness In Uncoupled Roof, they act as beams Nailed to Rafters with 2 x 75mm Nails

13 Joining Ridge Boards

14 Roofing Members Ridge Common Rafter Collar Tie Top Plate Hanging Beam
Purlin Top Plate Strutting Beam Strut Ceiling Joist Strut

15 Purlin Also known as Underpurlin Fixed to Underside of RAFTER
Runs parallel to ridge and wall plates Reduce span of RAFTER Will run full length of Gable Roof

16

17 Roofing Members Ridge Common Rafter Collar Tie Top Plate Hanging Beam
Purlin Top Plate Strutting Beam Strut Ceiling Joist Strut

18 Struts Transfer Loads to Load Bearing Walls

19

20

21

22

23 Roofing Members Ridge Common Rafter Collar Tie Top Plate Hanging Beam
Purlin Top Plate Strutting Beam Strut Ceiling Joist Strut

24 Collar Ties

25 Common Rafter Principles
Birdsmouth Max 1/3 Depth of Rafter

26 Common Rafter Principles
Span – From Birdsmouth to Birdsmouth Half Span – From Birdsmouth to Centre

27 Common Rafter Principles
True Rise –From Horizontal line that passes thru the Intersection of Birdsmouth Plumb Line &Top of Rafter To : vertically plumb up to the Apex NOTE – True Rise is not measured from TOP PLATE

28 A Closer Look Top Of Rafter Birds Mouth Top Plate Ceiling Joist
NOTE – True Rise is not measured from TOP PLATE

29 Common Rafter Principles
If Rise is taken from Top Plate to Apex pitch will be incorrect

30 Common Rafter Principles
Pitching Line x-y line

31 Common Rafter Principles
Measured to edge of Ridge Measured to centre of Ridge

32 Common Rafter Principles
Centre Line Length True Length True Length is usually what we need

33 Determine Rafter Length Mathematically
Determine Span = 2700mm Determine Half Span = 2700/2 = 1350mm Determine Rafter Run = 1350- Half Ridge Thickness = 19/2 = 9.5 Rafter Run = True Length Rafter = / Cos 25 = 1480 Rafter 90 x 45 Ridge 125 x 19

34 Overhang Plan always from external wall

35 Determine Rafter Length Mathematically
In this case Timber Famed Wall O/H = 450 / cos 25 = 497mm Roofing calculations are always measured from Birdsmouth or pitching point Rafter 90 x 45 Ridge 125 x 19

36 Determine Rafter Length Mathematically
In this case Brick Veneer Wall O/H = cos 25 = 662mm Total Rafter Length Timber Frame = = 1977mm Brick Veneer = = 2142mm Rafter 90 x 45 Ridge 125 x 19

37 Determine Rafter Length Graphically
Draw Roof Full-size Measure members directly Avoid using scaled drawing Scale use only for angles Rafter 90 x 45 Ridge 125 x 19

38 Determine Rafter Length Using Roofing Square
Use Calculator Press Tan 25 – what does this give you Therefore for every 1 metre run there is 0.466m rise Using the principle of similar triangles we half the size of the triangle

39 Press Tan 25 – what does this give you
Use Calculator Press Tan 25 – what does this give you Therefore for every 1 metre run there is 0.466m rise Using the principle of similar triangles we half the size of the triangle

40 Press Tan 25 – what does this give you
Use Calculator Press Tan 25 – what does this give you Therefore for every 1 metre run there is 0.466m rise Using the principle of similar triangles we half the size of the triangle

41 Using Similar Triangles
1341/500 = or = 2 r 341

42 Using Similar Triangles 1341/500 = 2.682 or = 2 r 341
Step out 2 full triangles Select Start Point Allowing for O/H

43 Intersection of Top of Rafter & Edge of Square

44 Using Similar Triangles 1341/500 = 2.682 or = 2 r 341
Step out 341 & use square to extend Step out 2 full triangles Select Start Point Allowing for O/H

45 Determine Roofing Angles used in Gable Roofs
Plumb Cut Foot Cut

46 Determining Angles with Roofing Square
When we set out rafter previously we determined plumb cut

47 Determining Angles with Roofing Square
Plumb Cut Foot Cut

48 Determining Angles Mathematically
Extend Line 90⁰ From Rafter

49 Determining Angles Mathematically
Extend Line 90⁰ From Rafter Extend Plumb Line

50 Determining Angles Mathematically
Extend Line 90⁰ From Rafter Extend Plumb Line Angle Formed is same as roof pitch

51 Determining Angles Mathematically
This angle must be 65⁰ 90 – 25 = 65 Right Angled Triangle Roof Pitch This angle must be 25⁰ 90 – 65 = 25

52 Determining Angles Mathematically
Extend Line 90⁰ From Rafter

53 Determining Angles Mathematically
Extend Line 90⁰ From Rafter Extend Plumb Line from same origin at top of Rafter

54 Determining Angles Mathematically
Extend Line 90⁰ From Rafter Extend Plumb Line from same origin at top of Rafter Angle Formed is same as roof pitch

55 Determining Angles Mathematically
Extend Line 90⁰ From Rafter Extend Plumb Line Angle Formed is same as roof pitch Offset = Tan (pitch) x width

56 Determining Angles Mathematically
Extend Line 90⁰ From Rafter Extend Plumb Line Angle Formed is same as roof pitch Offset = Tan (25⁰) x = 42

57 Determining Angles Mathematically
Next we can Determine our Birdsmouth Width across plumb cut = 90/ cos 25 = 99 Therefore max Birdsmouth = 33 Distance from top plate to top of Rafter = 66

58 Complete Q5 in Workbook

59 Determine Roof Angles Graphically
Plan – View We can only see rafter run

60 Determine Roof Angles Graphically
Extend Top Plate & Ridge

61 Determine Roof Angles Graphically
Extend Top Plate & Ridge Mark Rise

62 Determine Roof Angles Graphically
Plumb Cut Extend Top Plate & Ridge Mark Rise Draw Hypotenuse Foot Cut

63 Steps In Construction Gable Roof
Physically Confirm Span & Plates are Parallel Calculate True Rafter, Rise & Plumbcuts Mark out ceiling joists, rafters & ridge Install Ceiling Joists Cut Pattern Rafter & test to confirm Cut required rafters & install

64 Estimating Gable Roof - Rafter From Previous Ceiling Estimate
Pitch = 25⁰ Determine No of Ceiling Joists 12 250/ 600 = = = Therefore 22 set of Rafters = Verge = 48

65 Determine Rafter Length
Span = 6900

66 Determine Rafter Length
Span = 6900 Half Span = 3450

67 Determine Rafter Length
Span = 6900 Half Span = 3450 Run = 3450 – 9.5 (Half Ridge) =

68 Determine Rafter Length
Span = 6900 Half Span = 3450 Run = 3450 – 9.5 = True Length = / cos 24 =3766

69 Determine Rafter Length
Span = 6900 Half Span = 3450 Run = 3450 – 9.5 = True Length = / cos 24 =3766 Overhang = 450/cos 24 = 493

70 Determine Rafter Length
Span = 6900 Half Span = 3450 Run = 3450 – 9.5 = True Length = / cos 24 =3766 Overhang = 450/cos 24 = 493 Total Rafter = 4259

71 Estimating Sheet

72 Estimating Gable Roof - Purlin
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof Ridge 140 x 19 Purlin 90 x 70 F7 Purlin Run full length of Roof Do we need purlins

73 Span Required = 3766 Max Span 2600 3766/2600 = 1.4 Therefore 1 row required each side In First Instance we check single span Max Span = 1900

74 Estimating Gable Roof -Purlin
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof with Flush Gable & Raking Eaves Ridge 140 x 19 Purlin 90 x 70 F7 Purlin Run full length of Roof Do we need purlins Purlins Run Full Length x 150 (Joins) =

75 Estimating Sheet

76 Estimating Gable Roof - Ridge
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof with Flush Gable & Raking Eaves Ridge 140 x 19 Purlin 90 x 70 F7 Ridge Runs Full Length x 450 (O/H) x 300 (allow for joins) =14000mm Note – For Flush eaves there is no O/H ridge = 12500 Boxed eaves will require O/H ridge = 13400mm

77 Estimating Sheet

78 Estimating Gable Roof - Struts
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof with Flush Gable & Raking Eaves Ridge 140 x 19 Purlin 90 x 70 F7 Span 2700 Struts are Difficult to Estimate Develop a Best Guest Method Determine No Required 12500/2700 = 4.6 = 5 = 6 Each Side

79

80 Estimating Gable Roof - Struts
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof with Flush Gable & Raking Eaves Ridge 140 x 19 Purlin 90 x 70 F7 Span 2700 Struts are Difficult to Estimate Develop a Best Guest Method Half Rise x √2 x √2 Tan 24⁰ x 3441 x 2 = 3064 Determine No Required 12500/2700 = 4.6 = 5 = 6 Each Side

81 Estimating Sheet

82 Estimating Gable Roof – Collar Ties
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof with Flush Gable & Raking Eaves Ridge 140 x 19 Purlin 90 x 70 F7 Span 2700 Collar Ties 90 x 35 Collar Ties on Every 2nd Rafter On top of Purlins 22/2 = HALF SPAN 3450

83 Estimating Sheet

84 Estimating Gable Roof – Verge Trims
Pitch = 24⁰ Overhang 450 Rafter 90 x 45 F7 600 c to c Tiled Roof with Flush Gable & Raking Eaves Ridge 140 x 19 Purlin 90 x 70 F7 Span 2700 Collar Ties 90 x 35 True Length of Rafter

85 Rafter True length / 600 = 6.28 = 7 (Ridge Closes) = 33.6 Say 33.9

86 Estimating Sheet

87 One Row of Purlin Each Side


Download ppt "Gable Roof BCGCA3007B."

Similar presentations


Ads by Google