Cost and quantity calculation for RCC slab of 2 dismil and How to calculate total cost and material required for roof cast of 2 dismil building and also know about cost and quantity calculation for RCC slab per square foot

for the roof cast of 2 dismil = 870 square feet building roof slab, you have require Steel bar ,sand, cement and aggregate ,how we calculate quantity of cement, sand, Steel bar and aggregate required ,you know that for the casting of roof slab we used M20 mix concrete.

Roof slab |

## **M-20 mix grade of Concrete**

In M20 mix concrete M is stand for mix and numerical figure 20 is stand for characteristic of compressive strength 20N/mm2 after mixing and casting of roof slab, quantity of material in slab formation it calculated by M20 mix in which ratio of **sand cement and aggregate is 1: 1.5 :3**

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** ●M-mix Ratio :-1 : 1.5 : 3 in which one part is cement 1. 5 part is sand and 3 part is aggregate**

**Quantity of steel calculation for RCC slab**

** **● **Steel bar calculation**:- In roof slab there is a two types of Steel bar used main bar and cross bar:-

1) **Main bar:-** it is also called as shortist span bar usually used at bottom of slab having spacing 4 inch between the two bar, main bar used in shorter direction having 10 mm dia of Steel bar.

** 2) Cross bar:-** it is also called as longer span bar or distribution bar mainly used at top of the main bar, cross bar usually dia of 8mm Steel bar used in longer direction.

● **Given dimensions:-**

**Thickness of slab=5″**

Roof slab |

Area of slab = 870 sqft

M -20 -mix =1:1.5:3 (concrete)

** ****●Volume Calculation**:-

1) wet volume=Area × thicknessof slab

Vw= 870sqft× 5′

Vw= 870sqft×5/12′

Vw =361.92cft

If you want to convert it into cubic metre you should divide by 35.3147

1m3 =35.3147 cft

Wet volume=361.92/35.3147=10.86 m3

2) **Dry volume:-** we know that wet volume have water and bubbles it can be remove by vibrator or compressor machine so more quantity of material is required hence dry volume is increased by 54 percent of wet volume , so we can multiply 1.54 in wet volume to calculate dry volume

Vd =1.54 ×10.86 m3

Dry volume=16.724m3

** ****Weight calculation of Steel for slab**

quantity of steel required in roof slab is about 0.5℅ to 1% of dry volume then average is 0.75% of dry volume

Weight =0.75%of dry volume×density of steel

Density of steel is=7850 kg/m3

W =0.75/100×16.724m3 ×7850kg/m3

Weight=984.625kg

So weight of Steel bar is require for 870 square feet Roof slab= 984.624kg

If Market rate of steel bar is 60 rupees per kg then

total cost of Steel bar =984.62×rs 60

**Total cost= Rs 59077**

●**Sand Calculation**:-

In M20 ratio of sand cement and aggregate is 1:1.5:3 ,in this ratio 1.5 part is sand

Total proportion =1+1.5+3=5.5

Volume of sand in cft

Volume =1.5 /5.5×16.724×35.3147 cft

Volume of sand =161 cft

If market rate of 80 rupees per CFT then total cost of quantity of sand

**Total cost =rs80×161**

** =Rs 12880**

** ****●Cement calculation:- in** M20 mix 1 part is cement quantity

Weight of cement=1/5.5×dry volume in m3×density of cement

Density of cement=1450kg/m3

Weight =1/5.5×16.724 m3×1450 kg/m3 =4400Kg

1 bag cement =50kg

No.of bags =4400/50

=88 Bags cement

If market rate of cement is 350 rupees per bags then total cost

**Total cost =88 ×rs 350**

= **Rs 30863**

**●Aggregate Calculation:-** in M20 mix there is 3 part of aggregate quantity

Volume of aggregate=3/5.5×dry volume in CFT

Volume =3/5.5×16.724×35.3147 cft

Volume =322cft

If market rate of aggregate is is 70 rupees per CFT then total cost of aggregate

**Total cost =rs 70×322**

** Rs=rs22550**

● **total cost of material:-**

Cost of steel=rs 59077

Cost of cement=rs 30863

Cost of sand=rs 12880

Cost of stone=rs 22550

Labour charge and machine cost =rs 43500(approx)

**Total cost=Rs 168876**

Hence total cost of roof slab of 2400 square feet building require rs 434915

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