Post on 18-Dec-2015
Roof Bevels for Oblique Hip and Skew Gable
This Slide Show is to be used to explain the methods of Geometrically Developing the
bevels required for a
Skew Gabled and Oblique Hipped Roof.
Students are to complete their own drawings as the facilitator progresses
through the show
Lo
ng
Wa
ll
Span
Sh
ort
Wa
ll
Off
se
t
Identification of Main Aspects
'a'
'b'
1/2 Span 1/2 Span
Plan Long Hip
Identification of Main Aspects
Plan Short Hip
LL1
Crown End Rafter
Line of Centring Rafters
LL1= Level Line 1 is at 90° to the Short HipLL2= Level Line 2 is at 90° to the Long HipLL3= Level Line 3 is at 90° to the Crown End Rafter
Identification of Main Aspects
Development of Bevels
Bevels for rafters and Creepers
1.Draw Section
Section
Plan View
1. Plumb Bevel Common Rafter
2. Level Bevel Common Rafter
1. Plumb Bevel Common Rafter2. Level Bevel Common Rafter1
2
3 3. Edge Bevel Creeper to Gable Rafter
L.L.1
L.L.1
3.Edge Bevel Creeper to Gable Rafter
Draw a Creeper in Plan View in any Position along Gable Rafter
Develop it up to top cord of section
L.L.1
L.L.1
Measure up L..L.1 at 90o to top cord of section
Connect the 2 points
4
L.L.2
L.L.2LL2
LL2
4.Edge Bevel Creeper
to Long Hip
Draw a Creeper in Plan View in any Position along Long Hip
Develop it up to top cord of section
Measure up L..L.2 at 90o to top cord of section
Connect the 2 points
5
L.L.3
L.L.3
5. Edge Bevel Creeper to Short Hip
L.L.3
L.L.3
Draw a Creeper in Plan View in any Position along Short Hip
Develop it up to top cord of section
Measure up L..L.3 at 90o to top cord of section
Connect the 2 points
L.L.4
6L.L.4
6.Edge bevel Crown end Rafter
Develop a line, in any position, at 90o to the Crown End Rafter and extend it to the Centring rafter This will become L.L.4
Using you compass transfer the length on the Crown End rafter on to the Centring rafter
Develop it up to top cord of section
Measure up L..L.4 at 90o to top cord of section
Connect the 2 points
Bevels for Skew Gable and Backing Angle
Develop True Shape of Gable End
7
8
7. Plumb Bevel Gable Rafter
8. Level Bevel
gable Rafter
9
L.L.5
L.L.5
9. Edge Bevel Gable Rafter
Develop a line 90o to the skew gable to the ridge This will become L.L.5
Extend this line, still at 90o to the Skew Gable up to the top cord of the section
Measure up L..L.5 at 90o to top cord of section
Connect the 2 points
10
10. Backing Angle Gable Rafter
Develop a line 90o to the Top Cord and extend to the line of the Skew Gable
Develop a line at 90o to the Skew Gable and extend until it intersects with the outside of the plan View
Using your compass transfer the length of the first line onto the skew gable
Connect the 2 points
Bevels for Hips
11
12
11. Plumb Bevel Long Hip
12. Level Bevel Long Hip
Rise
11
12
13
L.L.6
L.L.6
13. Edge bevel Long Hip
Develop a line at 90o to the Long Hip Plan Length and extend to the Crown End Rafter this will become L.L.6
Continue line up to Top Cord true length Hip
Measure up L..L.6 at 90o to top cord of section
Connect the 2 points
14
1514. Plumb Bevel Short
Hip
15. Level Bevel Short Hip
Rise
14
15
16
L.L.7
L.L.7
16. Edge Bevel Short Hip
Develop a line at 90o to the Short Hip Plan Length and extend to the Crown End Rafter this will become L.L.7
Continue line up to Top Cord true length Hip
Measure up L..L.7 at 90o to top cord of section
Connect the 2 points
Bevels for Purlins
17 17. Face Bevel Purlin
to Long Hip
Develop a line at 90o to the top cord down to the bottom centre of the section
From the intersection on the top Cord project the point down until it hits the Long Hip
Using your compass transfer the length of the original line to the bottom cord of the section
Then project this point down past the Centring Rafter From were the first projection
meets the Long Hip develop a line parrel to the centring rafter until it meets the second projected line
From this point develop a line back to the Gathering Point
4
L.L.2
L.L.2
18
18. Edge Bevel Purlin to Long Hip
This Angle is the opposite to Edge Bevel Creeper Long Hip
(Development is as for Bevel 4)
19
19.Face Bevel Purlin to Gable Rafter Using Development for
Bevel 17
From were the first projection meets the Gable develop a line parrel to the centring rafter until it meets the second projected line
From this point develop a line back to the Gathering Point
3
L.L.1
L.L.1 20
20. Edge Bevel Purlin to Gable Rafter
This Angle is the opposite to Edge Bevel Creeper to Gable Rafter
(Development is as four bevel 3)
21
21.Face Bevel Purlin to Short Hip
Develop a line at 90o to the top cord down to the bottom centre of the section
From the intersection on the top Cord project the point down until it hits the Short Hip
Using your compass transfer the length of the original line to the bottom cord of the section
Then project this point down past the Centring Rafter
From were the first projection meets the Short Hip develop a line parrel to the centring rafter until it meets the second projected line
From this point develop a line back to the Gathering Point
5 L.L.32222. Edge Bevel Purlin to Short Hip
This Angle is the opposite to Edge Bevel Creeper to Short Hip
(Development is as four bevel 5)
1. Plumb Bevel Common Rafter2. Level Bevel Common Rafter1
2
4
4. Edge Bevel Creeper to Long Hip3 3. Edge Bevel Creeper to Gable Rafter5
5. Edge Bevel Creeper to Short Hip
L.L.1
L.L.1
L.L.2
L.L.2
L.L.3
L.L.3
L.L.4
6
6. Edge bevel Crown End Rafter
7
8
7. Plumb Bevel Gable Rafter8. Level Bevel Gable Rafter
9
9. Edge Bevel Gable Rafter
10
10. Backing Angle Gable Rafter
11
12
13
11. Plumb Bevel Long Hip12. Level Bevel Long Hip13.Edge Bevel Long Hip
14
15
14. Plumb Bevel Short Hip15. Level Bevel Short Hip
16
16. Edge Bevel Short Hip
L.L.5
L.L.5
L.L.6
L.L.6
L.L.7
L.L.7
17
17. Face Bevel Purlin to Long HIp
21
19. Face Bevel Purlin to Gable Rafter
18
18. Edge Bevel Purlin to Long Hip
20
20. Edge bevel Purlin to Gable Rafter
19
21. Face Bevel Purlin to Short Hip
22
22.Edge Bevel Purlin to Short Hip
L.L.4