Concrete roof or slab is made waterproof by applying stabilised bitumen sheets.The floor is first cleaned and then some bitumen is sprinkled over the surface and then bitumen stabilised sheets are rolled over the surface and joined with other at edges by applying heat through gas torch.

R.C.C slab roof 6mx3mx0.12m

R.C.C work 1:2:4: in footing excluding steel and it’s bending.

= 6.3×3.3×0.12 (0.15m in both sides)

= 2.495 cum

Steel reinforcing bars including bending-

Main bars:  12mm dia @0.89kg/m straight bars

24cm c/c . No (6.3-0.08)/24+1( side covers=2x4cm)

= 27Nos.

L=3.3-2covers+2hooks  (Take cover 4cm, hook 9xd

= 3.3-(2x4cm)+(2x9x12mm )

= 3.44m

27Nosx3.44×0.89 =82.66kg

Bent up bars: 26 Nos 12 mm dia @0.89kg/m

= 3.44m+0.08( add one depth)

= 3.52m

26Nosx3.52×0.89 =81.45kg

Distribution bars:  6mm dia  @0.22 kg/m

Bottom bars central portion 18cm c/c

(No.= 2.00/0.18+1=12 Nos

Bottom bars 2×3 two sides

Top bars two sides 2×3

Total No of bars = 12+2×3+2×3= 24Nos

L=6.3-2covers+2hooks  (Take cover 4cm, hook 9xd

= 6.3-(2x4cm)+(2x9x6mm )

= 6.33m


Total steel = 82.66+81.45+33.42



  1. R.C.C work 1:2:4: in beam excluding 2.495cum

steel and it’s bending

  1. Steel reinforcing bars including bending- 197.53kg 

 3     Centering & shuttering required:

Area of centering and shuttering