We have to find out the cost per sq ft concrete slab in India
For every new construction work, we needs to estimate the value of cost per sq ft concrete slab, column, footing, beam, wall and finishing work like plaster, paint, putty POP etc of construction so that every work and management done.
Let discuss the per sq ft cost of slab. So we have to cast the RCC Slab. In which the casting of slab includes many steps
STEP 1: Proper Levelling (छत का लेवल)
We need to level the wall or column at a height on which we want to construct the slab.
Generally rooms in home have 10 to 12 feet of height from floor level. so we need to take all the wall or pillar/column at that level.
STEP 2: Shuttering and Centering (छत की सैटरिंग)
When we get the the approx desired height of surrounding wall, then we have to fix the shuttering and centering.
Note that shuttering is very smooth and does not leek fresh concrete, if necessary use tape and oil over plates or ply. Shuttering must have sufficient strength to bear all the load coming on it.
STEP 3: Steel Reinforcement (छत का सरिया बंधाई)
After shuttering we have to reinforce the steel. Make sure the steel is provided according to drawing and design.
This is most important step, Check thoroughly thus the proper reinforcement is provided for one way slab or two way slab reinforcement are different.
One way/Two way Slab – length to width ratio is less than 2 in case of two way slab and more than 2 in case of one way slab.
STEP 4: Light Fitting (छत में लाइट फिटिंग)
Light fitting is done before slab concrete casting. The hollow pipe for electricity wires are placed in middle of it. Which is used for fan, light bulb or any other purpose after completion of construction.
STEP 5: RCC SLAB CONCRETE CASTING (आरसीसी छत की ढलाई/भराई )
This is the main work of any rcc slab construction work. The design Mix concrete is poured and placed over the shuttering work.
Make sure the mixed concrete is used within 30 minutes after mixing. Check the proper thickness of slab i.e. 125 mm, 150 mm or 175 mm generally.
Use CONCRETE VIBRATOR for proper compaction of concrete. The vibrator is necessary otherwise concrete remains loose or honeycomb.
Make sure worker does not import more water on it, As the water cement ratio of concrete increases the strength of concrete decreases.
You can provide slope as per your drain system.
Now we have to estimate the cost per sq ft concrete slab
STEP 1: Shuttering COST for RCC Slab (छत में सैटरिंग की कीमत )
First of all find out the shuttering area. So How to calculate the are of slab ?
For that lets take a slab of 30X40 ft. The slab also includes three beam of 1.0×1.5 ft along short sides.
so Plane Area of Slab = 30×40 = 1200 sq ft
Beam Area = 3×30.0x2.0 = 180 sq ft
Periphery of Slab Sides = 2x(30+40)x0.5 = 70 sq ft
Total area of shuttering of slab = 1450 sq ft
Now we have calculated the total area of shuttering and centering, so we have to find total cost of this area.
So we have to multiply this area to market rate of per sq ft.
The market rate is varies from place to place. It also depends upon the type of shuttering used. i.e. wooden ply, steel plates, for staging ballies or steel props etc.
wooden ballies are comparatively low in price because of easily availability. Steel props are used in very precious work, nowadays most govt work require steel porps example in metros. Because of the high strength and capacity of steel.
Generally rate is varies from 20 rupees to 40 rupees per sq ft.
As per BSR item the rate of shuttering is as follows:
- Centering and shuttering with plywood or steel sheets including strutting, propping, bracing both ways with wooden members and removal of formwork for superstructure up to 4.5 mtr above plinth, for:Suspended floors, roofs, landings, staircases, balconies, girders, cantilevers, bands , coping, bed plates, anchor blocks, sills, chhajjas lintel, beam etc. RATE IS 201 RUPEES PER SQUARE METRES.
- 20% extra cost is added if the steel props and bressings etc. are used instead of wooden member.
- 20 and 30 rupees per sqr mtr is added if the area of shuttering is circular having dia 10 mtr and more respectively.
- 16 rupees is extra added for every addition story and every 1 metre height.
- their is additional 13 rupees for beam more than 6 metres or sloping roof like dome.
NOTE that the rate in BSR is per square metres, we simply convert it into square feet by multiply it with 3.28*3.28 or 10.76 or vice versa.
Example: 1 sqm to sqft —- 13.283.28 = 10.7584 sqft.
Now the cost of shuttering is 1450 sqft * 20 rupees per sqft = 29000 rupees
we assume the cost of local shuttering 20 rupees per sqft
STEP 2: COST OF REINFORCEMENT IN SLAB (छत में सरिये की कीमत पता करे ?)
- Generally Steel rebar is used as reinforcement.
- The reinforcement is provided as per drawing and design.
- Indian Standard Code requirement
- The minimum percentage of reinforcement is 0.15% for mild steel and 0.12% for HYSD bar of the total cross sectional area of slab i.e. bD as per IS456:2000
- diameter of reinforcing bar shall not exceed one- eight of the total thickness of the slab i.e. (1/8*D)
- Generally the dia of bar is 10mm @150 mm c/c for a normal slab of thickness 6 inch (150mm)
- The cost of labour for reinforcing is generally 3 to 5 rupees per kg of steel.
BSR item for reinforcement is as follows:
- Providing and fabricating reinforcement for R.C.C. work including straightening, cutting, bending, placing in position and binding (including cost of binding wire) all complete up to floor three level.
Type of steel Rupees per Kg Mild steel and medium tensile bars (IS : 432) 64.00 Cold twisted bars (IS:1786) 64.00 Hot rolled deformed bars(IS:1139) 64.00 Thermo Mechanically treated bars(Tata/Sail) 66.00
- The rate is high for TATA/SAIL/JSW because these companies are trusted by govt.
Now the Cost of Steel = 2500 Kg * 66 rupees per Kg = 165000
we assume weight of steel is 2500 kg. You must calculate according to design.
STEP 3: COST OF CONCRETE CASTING (छत के लिए कंक्रीट की कीमत ?)
- The cost of concrete is analysed by type of mix you have to use.
- Their is lots of mix, mix refer to the ratio of cement sand and aggregate.
- As per Indian Standard Code their are lots of predefined mix like M20, M25 etc.
- Generally for slab we use M20 grade of concrete. Here M refer to Mix and 20 is the 28 days compressive strength in N/mm2. which is calculated by Cube testing.
- M20 => 1:1.5:3
- as we assume by volume 1 vessel is cement, 1.5 vessel is sand and 3 vessel is aggregate.
- Note that all the vessel/container have same volume.
- the concrete is best if it is mixed by mechanical mixer and used vibrator for compaction.
So we have to calculate the volume of concrete ?
Note that the local contractor may take cost as per area covered by slab.
But in the government tender the cost is calculated by the volume of slab i.e. beam and slab in cubic metres.
BSR item for concreting:
- Reinforced cement concrete work in beams, suspended floors, roofs, girders having slopes up to 15o , landings, balconies, shelves, chajjas, lintels, bands, plain windows sills, staircases and spiral staircases, up to floor three level including curing, compaction, finishing with rendering in cement sand mortar 1:3 (1-Cement:3-coarse sand) and making good and joints excluding the cost of centering, shuttering and reinforcement:
Type of MIX Rupees per Cumec M20 1:1.5:3 (1-Cement:1.5 coarse sand:3-graded stone aggregate 20 mm nominal size). 5080.00 M25 1:1:2 (1-Cement:1-coarse sand:2-graded stone aggregate 20 mm nominal size). 5661.00
Calculate volume of slab ?
Slab = 188.8.131.52 =16.73 m3 or cumec
Beam = 39.150.30*0.30 = 2.47 m3
Total = 16.73+2.47 = 19.20 m3
Cost = 19.20*5080 = 97536 rupees.
Please note that here we assume all the data, which is not similar on site
- Their may be column also, so shuttering are is deducted for column.
- The beam size is 1.0*1.5 ft, But we take 1.0 feet for calculation in shuttering as well as in concrete because the 0.5 ft if covered in slab itself.
Total Cost of shuttering for a slab 30×40 is as follows:
|Total amount =||291536|
Here we have calculated the cost of concrete slab.