Post on 15-Mar-2016
description
Broken Hip Roof
Lay out of Hip & Valley RoofRoof Pitch = 25⁰
Lay out of Hip & Valley RoofRoof Pitch = 25⁰
What Members define Creeper side cut
Lay out of Hip & Valley RoofRoof Pitch = 25⁰
What Members define Creeper side cut
• Half Span•Common Rafter
What Members define Valley Creeper side cut
Lay out of Hip & Valley RoofRoof Pitch = 25⁰
What Members define Creeper side cut
• Half Span•Common Rafter
What Members define Valley Creeper side cut
• Half Span•Common Rafter
Lay out of Hip & V RoofRoof Pitch = 25⁰
What Members define Creeper side cut
• Half Span•Common Rafter
Lay out of Broken Hip RoofRoof Pitch = 25⁰
No new bevels need to be developed
Lay out of Broken Hip RoofRoof Pitch = 25⁰
All Bevels and edge cuts are the same as a hip roof
Broken Hip As Span is not the same the rise will not be the same
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Common Rafter Major Span
Common Rafter Minor Span
Hip Rafter Major Span
Hip Rafter Minor Span
Valley Rafter Minor Span
Crown End Major Span
Crown End Minor Span
Centring Rafter Major Span
Centring Rafter Minor Span
Crippled Centring RafterBroken Hip
Gathering Point
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span =
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span
= Plan Length x Rafter Length / m= (1000 – 17.5) x 1.103= 982.5 x 1.103= 1084
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Common Rafter – Major SpanPlumb Cut
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span =
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span
= Plan Length x Rafter Length / m= (675 – 17.5) x 1.103= 657.5 x 1.103= 725
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Common Rafter – Minor SpanPlumb Cut
• As Major & Minor Span are the same pitch the plumb cuts must be the same
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof
= (½ Span – ½ Ridge) x Rise / m
= (1000 – 17.5) x 0.466
= 982.5 x 0.466
= 458
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458
= (½ Span Major – ½ Ridge) x Rise / m
= (1000 – 17.5) x 0.466
= 982.5 x 0.466
= 458
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof =
= (½ Span Minor – ½ Ridge) x Rise / m
= (675 – 17.5) x 0.466
= 657.5 x 0.466
= 306
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip RoofRoof Pitch = 25⁰
We recall that all hips & valleys bisect corners.
In this building it means that they are at 45⁰.
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span
= Plan Length Crown End Rafter x Hip length/m
= (1000 – 17.5) x 1.489
= 982.5 x 1.489
= 1.463
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Hip Rafter – Major SpanPlumb Cut
1.103
√2
0.466
1.489
1.000
Plumb Cut
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span =
= Plan Length Crown End Rafter x Hip length/m
= (0.675 – 17.5) x 1.489
= 657.5 x 1.489
= 979
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span =
= Plan Length Crown End Rafter x Hip length/m
= (0.675 – 17.5) x 1.489
= 657.5 x 1.489
= 979
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Valley is the same as the hip
Hip Rafter – Minor SpanPlumb Cut
• As Major & Minor Span are the same pitch the plumb cuts must be the same
1.103
√2
0.466
1.489
1.000
Plumb Cut
Lay out of Broken Hip RoofDetermine Centreline LengthCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major
Plan Length = ½ Span – Spacing + Correction
= 1000 – 300 + (1.414 x -17.5 + 17.5)
= 693 x Rafter Length / m
= 693 x 1.103
= 764
1.103
√2
0.466
1.489
1.000
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Note these measurements are directional as it goes back towards the Top Plate it must be a negative
Creepers– Major SpanPlumb Cut
• Creepers are the same pitch as the Common Rafters. They must have the same Plumb Cut
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Centreline LengthCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 406
Plan Length = ½ Span – Spacing + Correction
= 675 – 300 + (1.414 x -17.5 + 17.5)
= 368 x Rafter Length / m
= 368 x 1.103
= 406
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
1.103
√2
0.466
1.489
1.000
Creepers– Minor SpanPlumb Cut
• Creepers are the same pitch as the Common Rafters. They must have the same Plumb Cut
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 4061st Valley Creeper = 698
Plan Length = ½ Span + Valley Correction – ½ Ridge
= 675 - (1.414 x -17.5 + 17.5) – 17.5
= 633 x Rafter Length / m
= 633 x 1.103
= 698
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
1.103
√2
0.466
1.489
1.000
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Edge Bevel for Valley Creepers
What Triangle forms the Bevel
Crippled or Valley CreepersPlumb Cut
• Creepers are the same pitch as the Common Rafters. They must have the same Plumb Cut
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
We recall that all hips & valleys bisect corners.
In this building it means that they are at 45⁰.
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
1000-675 = 325
Hips at 45°
½ Span Major – ½ Span Minor
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
We recall that all hips & valleys bisect corners.
In this building it means that they are at 45⁰.
Therefore where the Broken Hip intersects the Ridge Minor Span must be 325mm from the Centreline of the Ridge Major Span
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
1000-675 = 325
Both Hips at 45°
½ Span Major – ½ Span Minor
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
= (½ Major Span – ½ Minor Span) x 2
Or
= Major Span – Minor Span
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
This must be 2x
This
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Crippled Centring Rafter
As the valley is at 45⁰ the intersection with the valley must be a further 325mm
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
To develop other Roofing Members we need to determine the plan length first
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 4061st Valley Creeper = 698Crippled Centring Rafter = 689
Plan Length = Major Span – Minor Span + Valley Correction – ½ Ridge
= 2000 – 1350 + (1.414 x -17.5 + 17.5) – 17.5
= 625 x Rafter Length / m
= 625 x 1.103
= 689
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
1.103
√2
0.466
1.489
1.000
Crippled Centring RafterPlumb Cut
• Crippled Centring Rafter is the same pitch as the Common Rafters.
• It must have the same Plumb Cut
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Edge Bevel for Crippled Centring Rafter
What Triangle forms the Bevel
Simple Bevel Development
1. Plumb Bevel Rafter2. Level Bevel Rafter3. Edge Bevel Creeper4. Edge Bevel Purlin5. Plumb Bevel Hip6. Level Bevel Hip7. Edge Bevel Hip8. Face Bevel Purlin
From Previous
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Every Valley Creeper must have an opposing creeper
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Every Valley Creeper must have an opposing creeper
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Every Valley Creeper must have an opposing creeper
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Every Valley Creeper must have an opposing creeper
From previous calculations we determined the following
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Every Valley Creeper must have an opposing creeper
Centreline length is the same as distance from the gathering point
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Every Valley Creeper must have an opposing creeper
To determine true length Long Pt
Centreline length 325
+/- Long Point Correction -7.5(-17.5 x 1.414 + 17.5)
Deduct ½ Ridge 17.5
Plan Length = 325 + -7.5 - 17.5
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 4061st Valley Creeper = 698Crippled Centring Rafter = 689Crippled Creeper Matching = 331
Plan Length = ½ Span Major – ½ Span Minor + Valley Correction – ½ Ridge
= 1000 – 675 + (1.414 x -17.5 + 17.5) – 17.5
= 300 x Rafter Length / m
= 300 x 1.103
= 331
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
1.103
√2
0.466
1.489
1.000
Crippled Matching RafterPlumb Cut
• Crippled Matching Rafter is the same pitch as the Common Rafters.
• It must have the same Plumb Cut
1.103
√2
0.466
1.489
1.000Plumb Cut
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 4061st Valley Creeper = 698Crippled Centring Rafter = 689Crippled Creeper Matching = 331 Creeper Shortening = 331
Rafter Spacing x Rafter Length / m
= 300 x 1.103
= 331
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
1.103
√2
0.466
1.489
1.000
Lay out of Broken Hip Roof
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 4061st Valley Creeper = 698Crippled Centring Rafter = 689Crippled Creeper Matching = 331 Creeper Shortening = 331
As both spans are the same pitch they are SIMILAR so Creeper Shortening is the same for both spans
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip Roof
So the roofing members we have previously looked at are determined the same way
Determine Required LengthsCommon Rafter Major Span = 1084Common Rafter Minor Span = 725Rise Main Roof = 458Rise Minor Roof = 306Hip Length Major Span = 1.463Hip Length Minor Span = 9791st Creeper Major = 7641st Creeper Minor = 4061st Valley Creeper = 698Crippled Centring Rafter = 689Crippled Creeper Matching = 331 Creeper Shortening = 331
Roof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35Rafter Spacing 300mm
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Edge Bevel for Crippled Centring Rafter
Edge Bevel for Crippled Centring Rafter is the CREEPER EDGE BEVEL
The same is for•Valley Creepers•Crippled Creepers
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Edge Bevel for Crippled Centring Rafter is the CREEPER EDGE BEVEL
The same is for•Valley Creepers•Crippled Creepers
It follows that all the The purlin bevels are The same as the hip end
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Determine Centreline Length Broken Hip
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Broken Hip Run325 x 1.414 = 460
1.103
√2
0.466
1.489
1.000
Determine Plan Centreline Length = 325
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Broken Hip Run325 x 1.414 = 460
1.103
√2
0.466
1.489
1.000
Determine Plan Centreline Length = 325
Centreline True Length
= Plan Length x Hip Rafter / m
= 325 x 1.489
= 484
Broken Hip Edge CorrectionAt Base
Broken Hip Edge CorrectionAt Base
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
Plumb cut is the same as the hipEdge Bevels are the same as the hip
1.103
√2
0.466
1.489
1.000
Lay out of Broken Hip RoofRoof Pitch = 25⁰
Rafter 90 x 35 @ 450 c to cHip Rafters 140 x 35Ridge 140 x 35
With the more complex roof. It is important to plan & set out the basic frame of the roof.