How much cement is required for 100 sqft rcc roof slab? and also know about how many cement bags required for 100 sq ft slab. You know that for the casting of roof slab we required nominal mix concrete like M20 mix 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

In this article we have to calculate cement required for 100 sqft 6 inch slab? And we know M20 mix Ratio is 1 : 1.5 : 3 in which one part is cement 1.5 part is sand and 3 part is aggregate

Roof slab casting is process of laying And putting concrete mix in horizontal direction and structure over brickwork. Cast of roof slab reinforcement main bar and cross bar in distributed over shuttering areas of roof slab and then we put concrete mix of M20 or m25 grade of concrete that is known as roof slab casting.

**How many cement bags required for 100 sqft roof slab?**

There are three types of thickness like 4 inch,5 inch & 6 inch are used in roof slab casting process. So we have to calculate cement required for 100 sq ft slab 4 inch thick, 5 inch thick and 6 inch thick.

Let us now calculate how many cement bags required for 100 sq ft slab 6 inch thick

How many cement bags required for 100 sq ft slab 6 inch thick

◆ Given dimensions:-

roof slab thickness ranging between 4 inch (100mm) to 6 inch (150mm) but in this calculation we take roof slab thickness is 6 inch (150mm) which is given

Roof slab thickness = 6″ = 0.5′

Area of slab = 100 sqft

Mix ratio = 1:1.5:3

**How much dry volume of concrete is required for 100 sqft 6 inch roof slab?**

1) wet volume =Area × thicknessof slab

Wet volume = 100 sqft × 0.5ft = 50 cft

2) Dry volume:-

we know that wet volume have voids and pore which filled with water and bubbles it can be remove by vibrator or compressor machine so more quantity of material is required.

dry volume means mixture of cement sand and aggregates concrete in dry condition have more voids and pores that are evaporated in wet condition and volume is decrease by 54 percent in wet condition and volume of dry concrete in increased by 54% , so we can multiply 1.54 in wet volume to calculate dry volume

Dry volume of concrete = 50 cft × 1.54 = 77 cft

1 cubic meter = 35.3147 cft

Dry volume of concrete in m3 = 77/35.3147 m3 = 2.180 m3

For 100 sqft 6 inch slab dry volume of concrete required is 2.180 m3

How much cement bags is required for 100 sqft 6 inch slab?

Mix ratio = 1:1.5:3 ( 1 part cement,1.5 part sand and 3 part is aggregate)

Total P = 1+1.5+3 = 5.5

Part of cement = 1/5.5

in M20 mix 1 part is cement quantity

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

Density of cement=1440kg/m3

Weight =1/5.5× 2.180 m3×1440 kg/m3

Weight of cement = 570.8 Kg

1 bag cement = 50kg

No. of bags of cement = 570.8/50

Number of cement bags are required for 100 sqft 6 inch slab = 11.4 bags.

● **Ans. :-** 11.4 bags (570.8 kgs) cement are required for a 100 sqft rcc roof slab 6 inch thick

**Cement required for 100 sq ft roof slab 5 inch thick**

How many cement bags required for 100 square feet 5 inch thick RCC slab? For this calculation we have given following

Area of rcc slab is 100 sq ft and their thickness is 5 inch which is equal to 0.417 feet, so first we calculate wet volume of concrete, for calculating wet by volume of concrete we multiply area of RCC slab and thickness.

Wet volume of concrete is equal to 100 sq ft × 0.417 ft = 41.7 cu ft.

For converting wet volume of concrete into dry volume of concrete we will multiply 1.54 into wet volume of concrete.

Dry volume of concrete is equal to 41.7 cuft × 1.54 = 64.218 cu ft

Cement required for 100 sq ft slab in m20 grade of concrete is equal to

= 1/5.5×64.218/35.3147 m3×1440 kg/m3

Weight of cement = 476.10 kg

no of cement bags required for 100 sq ft slab is calculated by dividing weight of cement by 50 because one bag cement weight is 50 kg

no of cement bags = 476.10/50 = 9.5

● **Ans. :-** 9.5 no of cement bags (476.10 kgs) are required for 100 sq ft rcc roof slab 5 inch thick m20 grade concrete

**Cement required for 100 sq ft roof slab 4 inch thick**

How many cement bags required for 100 square feet 4 inch thick RCC slab? For this calculation we have given following

Area of rcc slab is 100 sq ft and their thickness is 4 inch which is equal to 0.334 feet, so first we calculate wet volume of concrete, for calculating wet by volume of concrete we multiply area of RCC slab and thickness.

Wet volume of concrete is equal to 100 sq ft × 0.334 ft = 33.4 cu ft.

For converting wet volume of concrete into dry volume of concrete we will multiply 1.54 into wet volume of concrete.

Dry volume of concrete is equal to 33.4 cuft × 1.54 = 51.436 cu ft

Cement required for 100 sq ft slab in m20 grade of concrete is equal to

= 1/5.5×51.436/35.3147 m3×1440 kg/m3

Weight of cement = 381.3 kg

no of cement bags required for 100 sq ft slab is calculated by dividing weight of cement by 50 because one bag cement weight is 50 kg

no of cement bags = 381.30/50 = 7.6

● **Ans. :-** 7.6 no of cement bags (381.30 kgs) are required for 100 sq ft rcc roof slab 4 inch thick m20 grade concrete.

Now we have question how many cement bags required for 100 sq ft slab we have answer

● **Ans. :-** 7.6 bags (381.30 kgs), 9.5 bags (476.10 kgs) & 11.4 bags ( 570.8 kgs) cement are required for 100 sq ft rcc roof slab 4 inch, 5inch & 6 inch thick respectively in m20 grade of concrete.

**How much cement required for 1 sq.feet area:-** using M20 grade of concrete in roof slab casting, 1 sq.feet area of RCC slab require 0.095 bags (4.76kgs) of cement and incase of plastering of wall, it require 0.017bags (0.85kgs) of cement.

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**You should also visits:-**

**1)what is concrete and its types and properties**

**2) concrete quantity calculation for staircase and its formula**

Bismark Bissi says

I’m okay please.

Thank you

best regard.

Ranjan says

Superb explanation. Nice to share this to all people.

Ghouse mohiddin says

Very good job

Ghouse mohiddin says

Hello friends , first of all I would like to introduce about myself I am Ghouse mohiddin working as a civil contractor in Hyderabad