roofing estimation

1. ROOFING ANALYSIS OF PRICES
BQS458

2. CLAY ROOF TILES

3. NO OF TILES & LENGTH OF BATTEN

5. NAILS AND LABOR OUTPUT

6. CONCRETE ROOF TILES

12. ROOF COVERING
CORRUGATED ASBESTOS FREE CEMENT ROOFING SHEET
 Corrugated small sheet
 Corrugated small standard sheet
 Corrugated large sheet
 Corrugated large sheet Big Six
 Corrugated large angle sheet
STEEL ROOF SHEET

14. WASTAGE PERCENTAGE
TYPE OF ROOF SHEET
WIDTH
(mm)
SIDE LAPS
(mm)
NETT
WIDTH
(mm)
WASTAGE
RATE %
Corrugated small sheet 738 98 640 28.00
Corrugated small standard sheet 762 114 648 30.43
Corrugated large sheet 1075 75 1000 19.67
Corrugated large sheet Big Six 1086 52 1034 17.03
Corrugated large angle sheet 1100 100 1000 22.33

15. FORMULAE TO CALCULATE PERCENTAGE OF
LAPS AND WASTAGE
Standard sheeting size = 2400mm long x 762mm wide
Head laps = 150mm
Side laps = 114mm
Sheet area = 2.40 x 0.762 = 1.8288 m2
Enclosure area = (2.40 – 0.15) x (0.762 – 0.114) = 1.458m2
Percentage laps = 1.8288m2 – 1.458m2 x 100 =25.43%
1.458m2
Percentage wastage = 5.00%
= 30.43%

16. Standar
d
length
Standard width
sides laps
Standar
d
length
Standard width
Head laps
sides laps

17. LABOUR OUTPUT TO FIX ASBESTOS FREE CEMENT &
STEEL ROOF SHEET
Maximum roof
sheet length (mm)
1 roofer and 1 unskilled
labour(Hr/m2)
Small piece Large piece
1200 0.22 0.19
1800 0.2 0.17
2400 0.18 0.16
3000 0.17 0.15

19. END OF LECTURE