Download presentation

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 Sheet Metal Roof**

8
**Principles of Roofing Ridges are Level**

Rafters run at 90 to wall plates 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 (Nominal) 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

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 From Purlins to Load Bearing Walls

20
**Also Known as Barrap Straps**

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
Gable Roof Common Rafter

26
**Common Rafter Main Roofing Member Calculated same method as Gable**

Spaced Usually at 450mm to 600mm for Tiled Roofs & 600mm to 900mm for Sheet Roof Cut using a Pattern Rafter

27
Gable Roof Common Rafter Top Plate

28
**Top Plate Top Part of the Wall Frame**

Takes structural load from Roof and Transfers it to the wall studs Size must be determined from span tables

30
Pitching Line Pitching Line

31
Pitching Line Pitching Line Starts at top corner of Top Plate

32
Pitching Line Pitching Line Starts at top corner of Top Plate

33
**Pitching Line Pitching Line Starts at top corner of Top Plate**

Pitching line Runs Parallel to top of Rafter

34
**Pitching Line Pitching Line Starts at top corner of Top Plate**

Pitching line Runs Parallel to top of Rafter This establishes the Pitch of the Roof

35
**Pitching Line Pitching Line Starts at top corner of Top Plate**

If the pitching line went from top plate to top of roof the pitch is not correct or relevant. As you will see later it would make our calculations far harder

36
**Common Rafter Principles**

Span – From Birdsmouth to Birdsmouth Half Span – From Birdsmouth to Centre

37
**Common Rafter Principles**

Rise – Vertical height from top plate to intersections of pitching lines at Apex Rise is NOT measured to top of Rafter

38
**Common Rafter Principles**

If Rise is taken from Top Plate to Apex pitch will be incorrect

39
**Common Rafter Principles**

Measured to edge of Ridge Measured to centre of Ridge

40
**Confirmation of Learning**

Mark on Drawing in Workbook where, Centreline Length is measured to

41
Centreline Length Centre Line Length

42
**Confirmation of Learning**

Mark on Drawing in Workbook where, True Length is measured to Centre Line Length

43
**Common Rafter Principles**

Centre Line Length True Length True Length is usually what we need

44
**Confirmation Of Learning**

Mark on Drawing in Workbook where, Rafter is measured from at Base

45
**Measurement of Rafter Mark on Drawing in Workbook where,**

Rafter is measured from at Base Rafter is measured from this point

46
**Confirmation Of Learning**

Mark on Drawing in Workbook where, The Rafter Length is measured

47
**Measurement of Rafter Mark on Drawing in Workbook where,**

The Rafter Length is measured The Rafter Length is measure along the pitching line

48
**Measurement of Rafter Mark on Drawing in Workbook where,**

The Rafter Length is measured You may also measure on any line that is parallel to the pitching line so long as it is between Plumb lines that pass thru the required points.

49
**Determine Rafter Length Mathematically**

For every roof you must solve the 1m triangle based on the roof pitch Rafter 90 x 45 Ridge 125 x 19

50
The “1 Metre Triangle”

51
**Step 1 - Solve 1m Triangle Rafter Length per 1 metre of Plan length**

Rise per 1 metre of Plan Length 25° This is the a triangle based on the roof pitch Plan Length of 1 metre

52
**Step 1 - Solve 1m Triangle Rafter Length per 1 metre of Plan length**

Rise per 1 metre of Plan Length 25° This is always no matter what the Roof Pitch is Plan Length of 1 metre

53
Step 1 - Solve 1m Triangle These dimension will always change and are dependant on the Roof Pitch. These figures will need to be determined by you. Rafter Length per 1 metre of Plan length Rise per 1 metre of Plan Length 25° Plan Length of 1 metre

54
Step 1 - Solve 1m Triangle Solve all Unknown Sides of the a triangle based on the roof pitch Unknown Unknown 25° 1.000 Horizontal Travel = “Plan Length”

55
Step 1 - Solve 1m Triangle Solve all Unknown Sides of the a triangle based on the roof pitch Unknown 0.466 Rise = Plan Length x Tan (Pitch)° = x Tan 25° = 0.466 25° 1.000 Horizontal Travel = “Plan Length”

56
Step 1 - Solve 1m Triangle Rafter Length / m = Plan Length ÷ Cos (Pitch)° = ÷ Cos 25° = ÷ = 1.103 Solve all Unknown Sides of the a triangle based on the roof pitch 1.103 0.466 Rise = 1 x Tan 25° = 0.466 25° 1.000 Horizontal Travel = “Plan Length”

57
**Step 1 - Solved 1m Triangle**

For any roof of 25° the Rafter Length per 1 m of Plan Length For any roof of 25° the Rise per 1 m of Plan Length 1.103 0.466 25° 1.000 Horizontal Travel = “Plan Length”

58
**Confirmation of Learning**

Determine the following 1 metre triangles 16° 20° 45° 30°

59
**Confirmation of Learning**

Determine the following 1 metre triangles 1.064 1.040 0.287 0.364 16° 20° 1.000 1.414 1.000 1.155 0.577 45° 30° 1.000 1.000

60
**Determine Centreline Length**

Ridge Centreline Length is to the Centre of the Roof ½ Span

61
**Definition – Plan Length**

“Plan Length” is the Horizontal (Level) Distance a Roofing Member Travels A Rafter is 3310 and is pitched at 25° 3310 25° Plan Length

62
**Definition – Plan Length**

Plan Length is the Horizontal (Level) Distance a Roofing Member Travels 3310 The Horizontal Distance that the Rafter Travels is its “PLAN LENGTH In this case is 3000 25° 3000

63
**Definition – Plan Length**

Plan Length is the Horizontal (Level) Distance a Roofing Member Travels 3310 It is important when determining any Rafter Hip Creeper Valley etc., To first determine its plan length 25° 3000

64
**Confirmation Of Learning**

What is the “Plan Length” of this Rafter? 2750 1887 2000

65
**Confirmation Of Learning**

What is the “Plan Length” of this Rafter? 2750 1887 2000 This is the plan length

66
Centreline Length What is the plan length we need to use to determine the Centreline Length of the common rafter below ? Rafter 90 x 45 Ridge 125 x 19

67
Centreline Length What is the plan length we need to use to determine the Centreline Length of the common rafter below ? Rafter 90 x 45 Ridge 125 x 19

68
**Step 2 – Determine Plan Length Centreline Length**

Determine how far the rafter travels HORIZONTALLY PLAN LENGTH 1.103 0.466 25° 1350(1/2 Span) Plan Length 1 “Plan Length” = ½ Span = 1350

69
**Step 2 – Determine Plan Length Centreline Length**

Determine how far the rafter travels HORIZONTALLY PLAN LENGTH 1.103 0.466 25° 1350(1/2 Span) Plan Length 1 For any Rafter (or Hip) you must first determine the Horizontal Travel i.e. PLAN LENGTH “Plan Length” = ½ Span = 1350 Plan Length= 1350

70
**Principle Of Similar Triangles**

If all 3 angles of 2 triangles are equal There will be the same proportional difference between the corresponding sides of the triangle 65° 2.206 2x 1.862 1.103 65° 0.466 25° 25° 1 2 The right hand triangle is 2x the size of the “1 meter triangle”

71
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 This is our “1 meter” triangle

72
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 This is the TARGET triangle formed by the rafter

73
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles

74
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths

75
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 Target Triangle 1 Metre Triangle The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of “TARGET” triangle ÷ Plan length “1 metre” triangle

76
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of TARGET triangle ÷ Plan length “1 meter” triangle Ratio = 2 ÷ 1 Ratio = 2

77
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of TARGET triangle ÷ Plan length “1 meter” triangle Ratio = 2 ÷ 1 Ratio = 2 We will call this the triangle multiplier

78
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of TARGET triangle ÷ Plan length “1 meter” triangle Ratio = 2 ÷ 1 Ratio = 2 For the Common Rafter as we use the “1 meter” triangle, the Triangle Multiplier will always = Plan length of the Target triangle

79
**Step 3 – Determine Rafter Length Centreline Length**

1489 1.103 0.466 25° 1350 ½ Span Plan Length 1 Rafter Length = Plan Length x Rafter Length per metre (RL/m) Rafter Length = x 1.103 Rafter Length = 1489

80
**Step 4 – Determine Rise (If Required) Centreline Length**

1489 629 1.103 0.466 25° 1350 (1/2 Span) Plan Length 1 Total Rise = Horizontal Travel x Rise per metre Total Rise = 1350 x 0.466 Total Rise = 629

81
True Length What is the plan length we need to use to determine the True Length of the common rafter below ? Rafter 90 x 45 Ridge 125 x 19

82
True Length What is the plan length we need to use to determine the True Length of the common rafter below ? Rafter 90 x 45 Ridge 125 x 19

83
**Determine Centreline Length**

Ridge 125 x19 True Length is to the Side of the Ridge ½ Span – ½ Ridge Thickness

84
**Step 2 – Determine Plan Length True Length**

Ridge 125 x 19 Determine how far the rafter travels HORIZONTALLY PLAN LENGTH 1.103 0.466 25° 1341 Plan Length 1 “Plan Length” = ½ Span – ½ Ridge Thickness = 1350 – 9.5 = 1341

85
**Step 2 – Determine Plan Length Trur Length**

Ridge 125 x 19 Determine how far the rafter travels HORIZONTALLY PLAN LENGTH 1.103 0.466 25° 1350(1/2 Span) Plan Length 1 For any Rafter (or Hip) you must first determine the Horizontal Travel i.e. PLAN LENGTH “Plan Length” = 1341

86
**Principle Of Similar Triangles**

If all 3 angles of 2 triangles are equal There will be the same proportional difference between the corresponding sides of the triangle 65° 2.206 2x 1.862 1.103 65° 0.466 25° 25° 1 2 The right hand triangle is 2x the size of the “1 meter triangle”

87
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 This is our “1 meter” triangle

88
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 This is the TARGET triangle formed by the rafter

89
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles

90
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths

91
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 Target Triangle 1 Metre Triangle The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of “TARGET” triangle ÷ Plan length “1 metre” triangle

92
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of TARGET triangle ÷ Plan length “1 meter” triangle Ratio = 2 ÷ 1 Ratio = 2

93
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of TARGET triangle ÷ Plan length “1 meter” triangle Ratio = 2 ÷ 1 Ratio = 2 We will call this the triangle multiplier

94
**Understanding the Principle Of Similar Triangles**

65° 2.206 1.862 1.103 65° 0.466 25° 25° 1 2 The first step is to determine proportional ratio between the triangles To determine this we ALWAYS determine using the PLAN lengths Ratio = Plan length of TARGET triangle ÷ Plan length “1 meter” triangle Ratio = 2 ÷ 1 Ratio = 2 For the Common Rafter as we use the “1 meter” triangle, the Triangle Multiplier will always = Plan length of the Target triangle

95
**Step 3 – Determine Rafter Length True Length**

1479 1.103 0.466 25° 1341 Plan Length 1 Rafter Length = Plan Length x Rafter Length per metre (RL/m) Rafter Length = x 1.103 Rafter Length = 1479

96
**Step 4 – Determine Rise (If Required) Centreline Length**

1479 625 1.103 0.466 25° 1341 Plan Length 1 Total Rise = Horizontal Travel x Rise per metre Total Rise = 1341 x 0.466 Total Rise = 625

97
**Overhang on a Plan is always measured from external wall**

98
**Determine Rafter Length Mathematically (Version 1)**

In this case Timber Famed Wall Determine Rafter Length per m = 1 ÷ cos 25 = per m Rafter = Run x 1.103 = x 1.103 = 1.480 Roofing calculations are always measured from Birdsmouth or pitching point Rafter 90 x 45 Ridge 125 x 19

99
**Determine Rafter Length Mathematically**

In this case Timber Famed Wall Determine Total Rafter Length Rafter = Plan Length x 1.103 = x 1.103 = 1791 x 1.103 = 1.975 Roofing calculations are always measured from Birdsmouth or pitching point Rafter 90 x 45 Ridge 125 x 19

100
**Determine Rafter Length Mathematically**

In this case Brick Veneer Wall O/H = = 600mm Total Rafter Length = x 1.103 = 1961 x 1.103 = 2.163 Rafter 90 x 45 Ridge 125 x 19

101
**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

102
**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

103
**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

104
**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

105
**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

106
**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

107
**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

108
**Using Similar Triangles**

1341/500 = or = 2 r 341

109
**Using Similar Triangles 1341/500 = 2.682 or = 2 r 341**

Step out 2 full triangles Select Start Point Allowing for O/H

110
**Intersection of Top of Rafter & Edge of Square**

111
**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

112
**Determine Roofing Angles used in Gable Roofs**

Plumb Cut Foot Cut

113
**Determining Angles with Roofing Square**

When we set out rafter previously we determined plumb cut

114
**Determining Angles with Roofing Square**

Plumb Cut Foot Cut

115
**Determining Angles Mathematically**

Extend Line 90⁰ From Rafter

116
**Determining Angles Mathematically**

Extend Line 90⁰ From Rafter Extend Plumb Line

117
**Determining Angles Mathematically**

Extend Line 90⁰ From Rafter Extend Plumb Line Angle Formed is same as roof pitch

118
**Determining Angles Mathematically**

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

119
**Determining Angles Mathematically**

Extend Line 90⁰ From Rafter

120
**Determining Angles Mathematically**

Extend Line 90⁰ From Rafter Extend Plumb Line from same origin at top of Rafter

121
**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

122
**Determining Angles Mathematically**

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

123
**Determining Angles Mathematically**

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

124
**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

125
Complete Q5 in Workbook

126
**Determine Roof Angles Graphically**

Plan – View We can only see rafter run

127
**Determine Roof Angles Graphically**

Extend Top Plate & Ridge

128
**Determine Roof Angles Graphically**

Extend Top Plate & Ridge Mark Rise

129
**Determine Roof Angles Graphically**

Plumb Cut Extend Top Plate & Ridge Mark Rise Draw Hypotenuse Foot Cut

130
**Steps In Construction Gable Roof**

Physically Confirm Span & Plates are Parallel Calculate True Rafter, Rise & Plumb cuts Mark out ceiling joists, rafters & ridge Install Ceiling Joists Cut Pattern Rafter & test to confirm Cut required rafters & install

131
**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

132
**Determine Rafter Length**

Span = 6900 Pitch 24°

133
**Determine Rafter Length**

Span = 6900 Pitch 24° 1

134
**Determine Rafter Length**

Span = 6900 Pitch 24° 0.4451 1

135
**Determine Rafter Length**

Span = 6900 Pitch 24° Rafter =√ ( ) 0.4451 1

136
**Determine Rafter Length**

Span = 6900 Pitch 24° 1.095 Rafter =√ ( ) = 1.095 0.4451 1

137
**Determine Rafter Length**

Span = 6900 Pitch 24° Rafter = 1

138
**Determine Rafter Length**

Span = 6900 Pitch 24° 1.095 Rafter =1 ÷ Cos 24° 1

139
**Determine Rafter Length**

Span = 6900 Pitch 24° 1.095 Rafter =1 ÷ Cos 24° = 1.095 1

140
**Determine Rafter Length**

Span = 6900 Half Span = 3450

141
**Determine Rafter Length**

Span = 6900 Half Span = 3450 Run = 3450 – 9.5 (Half Ridge) =

142
**Determine Rafter Length**

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

143
**Determine Rafter Length**

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

144
**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

145
**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 Allow for plumb cut = 41 Minimum Rafter Length = 4300 Order = 4500 Allow for Plumb cut Tan (Pitch) x Width = Tan 24° x 90 = 41

146
Estimating Sheet

147
**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

148
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

149
**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) =

150
Estimating Sheet

151
**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

152
Estimating Sheet

153
**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

155
**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

156
Estimating Sheet

157
**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

158
Estimating Sheet

159
**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

160
Rafter True length / 600 = 6.28 = 7 (Ridge Closes) = 33.6 Say 33.9

161
Estimating Sheet

162
**One Row of Purlin Each Side**

163
Gable Roof Common Rafter

164
**Top Plate Part of the Wall Frame Takes structural load from Roof**

Size must be determined from span tables

165
Top Plate

166
Exercise 1 Determine Required Top Plate Size

167
**Common Rafter Principles**

Birdsmouth Max 1/3 Depth of Rafter

Similar presentations

Presentation is loading. Please wait....

OK

Hip Rafters • Hip Jack Rafters • Constructing Hip Roofs

Hip Rafters • Hip Jack Rafters • Constructing Hip Roofs

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Free ppt on emotional intelligence Ppt on electricity from waste materials Ppt on statistics and probability help Ppt on digital media broadcasting Ppt on sri lanka history Ppt on data handling for class 3 Ppt on data handling for class 7th results Ppt on forest in india Ppt on trial and error movie Ppt on ministry of corporate affairs