1. Estimating Hip Roofs

2. Estimating Hip Roofs- Rafters
Pitch = 24⁰
Note – Change of Layout of Ceiling Joists to Accommodate Creepers
Determine No of Rafters
12 500/ 600 = =
= 22 Rafters each side
= 44

3. Determine Rafter Length
Span = 6900

4. Determine Rafter Length
Span = 6900
Half Span = 3450

5. Determine Rafter Length
Span = 6900
Half Span = 3450
Run = 3450

6. Determine Rafter Length
Span = 6900
Half Span = 3450
Run = 3450 – 9.5 =
Run of Eaves = 600
Total Run =
= 4050
Total Length =4050/ cos 24
= offset
=4473

7. Estimating Sheet

8. Estimating Hip Roof - Ridge
Pitch = 24⁰
Overhang 450
Rafter 90 x 45 F7
600 c to c
Ridge 140 x 19
Purlin 90 x 70 F7
Ridge Runs Between Crown End
x 3600 = 5300
½ Rafter Thickness for each hip end
=5345 mm

9. Estimating Sheet

10. Estimating Hip 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
Spacing 2200 centres
1 Row Purlins at Centre Span
Deduct ¼ span for every hip
12500 – 1725 – 1725 = 9050 allow 150 for joints = 9200
6900 – 1725 – 1725 = 3450

11. Estimating Sheet

12. Estimating Hip Roof – Hip Rafter
Pitch = 24⁰
Overhang 450
Rafter 90 x 45 F7
600 c to c
Hip 140 x 19
Ridge 140 x 19
Purlin 90 x 70 F7
Method 1
Hip = √(Rise² + ((Half Span + O/H) x 1.414)²
Hip = √(1.803² + (( ) x 1.414)² )
Hip = √( )
Hip = for Plumb Cut
Hip = 6.153
Method 2
Hip = √(Total Rafter² + (Half Span + O/H)²
Hip = √(4433² + ( )² )
Hip = √( )
Hip = for Plumb Cut
Hip = 6.154

13. Estimating Sheet

14. 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
9.050/2700 =3.4= 4= 5 Each Side
Determine No Required
3.450/2700 =1.28= 2= 3 Each Side

16. 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
Length
Half Rise x √2 x √2
(3.450/2 x tan24) x 2
0.768 x 2 = 1.536

17. Estimating Sheet

18. 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
Length of Ridge / Rafter Spacing / 2
22/2 = HALF SPAN
3450

19. Estimating Sheet

20. Estimating Tile Quantities
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
Calculate Roof Area

21. Determine Rafter Length
Span = 6900
Half Span = 3450
Run = 3450 – 9.5 =
Run of Eaves = 600
Total Run =
= 4050
Total Length =4050/ cos 24
= offset
=4473

22. Estimating Tile Quantities
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 = 4433
Area of Roof = 4433 x ( x 0.45) x 2
= x 7 tiles per sqm =