The amount of steel required for an RCC (Reinforced Concrete) roof slab depends on various factors such as the thickness of the slab, the type of steel used, and the structural requirements. Typically, the quantity of steel is measured in kilograms per cubic meter (kg/m³) of concrete. A common range is 80 to 120 kg/m³ for residential construction. For a rough estimate, you can use a quantity of around 1% to 1.5% of the concrete volume as steel reinforcement.

How much steel required for 100 sq ft rcc roof slab? Hi guys in this article we know about steel required for 100 sq ft slab 4 inch,5inch and 6 inch thickness.

In RCC slab casting process quantity of steel required for slab is depend on many factors like thickness of slab, type of building structure, residential building, low rise building and construction of high rise building.

Steel required for 100 sq ft slab also depends on load bearing structure and we know that slab transfer its dead load and live load to beam and beam transfer its to column, column transfer load to footing and finally footing transfer load into bed of soil.

There are two types of Steel used in roof slab casting process 1) main rebar & 2) cross bar.

**● Main rebar :-** main reinforcement are used in shortest span of slab that’s why it is also known as shortest rebar, generally main reinforcement are used in bottom of slab have higher dia of steel.

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**● Distribution rebar:-** distribution reinforcement are used in longer span of slab that’s why it is also known as longest rebar, generally distribution reinforcement are used in top of slab have lesser dia of steel actually distribution bar put over main bar in opposite direction that’s why it is also known as cross bar.

**● Thumb Rule for Steel in RCC slab :- **In general, Thumb Rule for Steel quantity required for construction of RCC roof slab is ranging between between 80 Kg to 90 kg per cubic metre per wet volume of concrete of slab.

**Steel required for 100 sq ft roof slab**

We we have given area of RCC slab is equal to 100 square feet and thickness of RCC slab is 4 inch, 5 inch and 6 inch thick.

The typical amount of steel required for construction of 100 sq ft (square feet) reinforced concrete slab (RCC roof) is ranging between 85kg and 95kg. Therefore RCC roof slab requires 85-95 kg of steel per 100 square feet.

**Steel required for 100 sq ft slab 4 inch thickness**

Area of RCC slab is equal to 100 square feet and thickness of RCC slab 4 inch, then volume of concrete it is calculated by multiplying area and thickness of slab.

Wet volume of concrete is equal to multiplication of area and thickness of slab 100 sq ft × 4 inch/12 = 33.4 cu ft, so wet volume of concrete equal to 33.4 cu ft.

Now we convert volume of concrete into cubic metre, 1m3 = 35.3147 cuft, then wet volume of concrete in cubic meter = 33.4/35.3147 = 0.944 m3, now volume of concrete is equal to 0.944 m3.

Thumb rule for Steel required for RCC slab is 80 kgs/m3, then quantity of steel required for 100 sq ft ( 0.944 m3) rcc slab is equal to = 80 × 0.944 = 75 kg.

At 4″ thickness, the total amount of steel required for **100 sq ft** (0.944 cubic meters) RCC roof slab is equal to = 80 × 0.944 = **75 kg**. This means, **75 kg** of steel is needed per **100 sq ft** (square feet) of **4-inch** thick RCC roof slab.

Rod calculation for roof: The quantity of Rod (steel) required for roof slab is 80 kg/m3 of concrete volume. If your roof slab is 10 meters in length, 8 meters width and 100 mm thick. Then volume of concrete required for roof slab = 10 × 8 × 0.1 = 8m3, then amount of rods for 8m3 roof = 8 ×80 = 640 kg (or 0.64 tons).

**Steel required for 1 sq ft RCC roof slab 4 inch thick thickness**

Volume of 1 sq ft of RCC slab at 4 inches thick in m3 = (1 × 4/12) ÷ 35.32 = 0.00944 m3

At 4″ thickness, the total quantity of steel required for **1 sq ft** (0.00944 cubic meter) RCC roof slab is equal to = 80 × 0.00944 = **0.75 kg**. This means, **0.75 kg** of steel is needed **per sq ft** of **4-inch** thick RCC slab.

**Steel required for 1 sq ft RCC roof slab 5 inch thickness**

Volume of 1 sq ft of RCC slab at 5 inches thick in m3 = (1 × 5/12) ÷ 35.32 = 0.0118 m3

At 5″ thickness, the total quantity of steel required for **1 sq ft** (0.0118 cubic meters) RCC roof slab is equal to = 80 × 0.0118 = **0.944 kg**. This means, **0.944 kg** of steel is needed **per sq ft** of **5-inch** thick RCC roof slab.

**Steel required for 1 sq ft RCC roof slab 6 inch thickness**

Volume of 1 sq ft of RCC slab at 6 inches thick in m3 = (1 × 6/12) ÷ 35.32 = 0.0142 m3

At 6″ thickness, the total quantity of steel required for **1 sq ft** (0.0142 cubic meter) RCC roof slab is equal to = 80 × 0.0142 = **1.132 kg**. This means, **1.132 kg** of steel is needed per sq ft of 6**-inch** thick RCC roof slab.

**Steel required for 1 sq.m RCC roof slab 150mm thickness**

Volume of 1 sq.m (square meter) of RCC slab at 150 mm thick in m3 = (1 × 0.15) = 0.15 m3

At 150 mm thickness, the total quantity of steel required for **1 sq.m** (0.15 cubic meter) RCC roof slab is equal to = 80 × 0.15 = **12kg**. This means, **12 kg** of steel is needed per sq.m (square meter) of 150 mm thick RCC roof slab.

**Steel required for 1 sq.m RCC roof slab 125mm thick**

Volume of 1 sq.m (square meter) of RCC slab at 125 mm thick in m3 = (1 × 0.125) = 0.125 m3

At 125 mm thickness, the total quantity of steel required for **1 sq.m** (0.125 cubic meter) RCC roof slab is equal to = 80 × 0.125 = **10kg**. This means, **10 kg** of steel is needed per sq.m (square meter) of 125 mm thick RCC roof slab.

**Steel required for 1 sq.m RCC roof slab 100mm thick**

Volume of 1 sq.m (square meter) of RCC slab at 100 mm thick in m3 = (1 × 0.1) = 0.1 m3

At 100 mm thickness, the total quantity of steel required for **1 sq.m** (0.1 cubic meter) RCC roof slab is equal to = 80 × 0.1 = 8**kg**. This means, 8** kg** of steel is needed per sq.m (square meter) of 100 mm thick RCC roof slab.

**Steel required for 100 sq ft slab 5 inch thickness**

Area of RCC slab is equal to 100 square feet and thickness of RCC slab 5 inch,then volume of concrete it is calculated by multiplying area and thickness of slab.

Wet volume of concrete is equal to multiplication of area and thickness of slab 100 sq ft × 5 inch/12 = 41.7 cu ft, so wet volume of concrete equal to 41.7 cu ft.

Now we convert volume of concrete into cubic metre, 1m3 = 35.32 CFT, then wet volume of concrete in cubic meter = 41.7/35.32 = 1.18 m3, now volume of concrete is equal to 1.18 m3.

Thumb rule for Steel required for RCC slab is 80 kgs/m3, then quantity of steel required for 100 sq ft ( 1.18 m3) rcc roof slab is equal to = 80 × 1.18 = 95 kg

At 5″ thickness, the total quantity of steel required for **100 sq ft** (1.18 cubic meters) RCC roof slab is equal to = 80 × 1.18 = **95 kg**. This means, **95 kg** of steel is needed per **100 sq ft** (square feet) of **5-inch** thick RCC roof slab.

**Steel required for 100 sq ft roof slab 6 inch thickness**

Area of RCC slab is equal to 100 square feet and thickness of RCC slab 6 inch,then volume of concrete it is calculated by multiplying area and thickness of slab.

Wet volume of concrete is equal to multiplication of area and thickness of slab 100 sq ft × 6 inch/12 = 50 cu ft, so wet volume of concrete equal to 50 cu ft.

Now we convert volume of concrete into cubic metre, 1m3 = 35.3147 cuft, then wet volume of concrete in cubic meter = 50/35.3147 = 1.416 m3, now volume of concrete is equal to 1.416 m3.

Thumb rule for Steel required for RCC slab is 80 kgs/m3, then quantity of steel required for 100 sq ft ( 1.416 m3) rcc slab is equal to = 80 × 1.416 = 113 kg.

At 6″ thickness, the total quantity of steel required for **100 sq ft** (1.416 cubic meters) RCC roof slab is equal to = 80 × 1.416 = **113 Kg**. This means, **113 kg** of steel is needed per **100 sq ft** (square feet) of **6-inch** thick RCC roof slab.

75.5 kgs, 94.5 kgs & 113.3 Kgs steel quantity are required for 100 sq ft 4 inch, 5 inch & 6 inch thick rcc roof slab.

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**Conclusions:-**

That’s 75 kg of steel quantity are required for 100 sq ft and 4 inch thick RCC roof slab. For the same area, 95 kg of steel with a thickness 5 inches and 113 kg of steel with a thickness of 6 inches are required.