A covered built-up area measured at the floor level of any building’s storey or (at the floor level of the building’s basement) is called the plinth area. It is the measure of a building’s useable area.
It is also known as the built-up area that is the whole area occupied by the building along with external and internal walls. It is usually 10% to 20 % higher than the carpet area.
It should be computed for the enclosed area by measuring the external building’s dimensions at the floor level. The courtyard and other open areas will not include in the plinth area.
Measurement of the area of the plinth is essential for estimating the cost of the building.
Plinth Area Measurement of a Building
For the plinth area measurement, we take the dimensions (lengths and widths) nearest to 0.01 m and the area rounded to 0.01 m2. In the Case of the feet system, we measure the length to the nearest 1 inch.
During the measurement, items such as Floors, including the top floor, which may be partly covered, stilled floor (Floor without cladding), Basement, Mezzanine floor, Garage, are measured separately.
The following will include in the measurement
As per Is 3861-2002 following area will include in the plinth area of the building.
- Total floors, wall’s area at the floor level except plinth offset if any.
- Internal shaft area for installing sanitary and garbage chute, telecom, electrical, if the area is less than 2 square meters.
- Air condition dut and lift well with landing.
- The area of the habitable room or barsati and stair cover or mumty at terrace level
- Poarch area excluding cantilevered.
The following will not include in the measurement
- Area of cantilever porch, balcony and loft.
- Internal shaft area for installing sanitary and garbage chute. If the area is more than 2 Sqm.
- Area of domes, turrets, towers etc., extending above the terrace level, not making a storey at terrace level.
- Architectural bends, cornices etc.
- Vertical sun breakers or box louvres, Sunshades are projecting out.
- Area of open platform, spiral staircase as well as landing and terrace at first floor.
Area of Wall in Plinth Area Calculation
The area of walls is also involved in the plinth area calculation. It is the space occupied by walls on the plan on any floor. If the height of any finishing or dado is greater than one meter, it is included in wall thickness. The items that are included in the wall area are as follows.
- The area covered by opening like doors on plan.
- Supports like central pillars other such obstacles within the plinth area irrespective of their positions.
- If the area of plaster along the wall exceed 300 cm2, then it is included.
- Built-in shelves, wardrobes and cupboards are seeming within a height of 2.2m from the floor.
- Fireplace extending beyond the wall face located in living or bedroom
- Flues within the wall.
The following will not include in the wall area:
- If the area of plaster along the wall not passing the area of 300 cm2.
- Platforms projection exceeding the wall face
Plinth Area Estimate
It is prepared based on the building’s plinth area. It is a rough or approximate cost estimate in which the building’s plinth area is multiplied by the plinth area rate to get the building cost.
The rate for the unit plinth area is determined from the cost of the similar building that already exists, having similar specification, construction and height in the locality so that the estimation is close enough.
This estimate is only approximate, and it is a preliminary estimate to know the estimated cost previously. Following items are added to the building cost to get the total cost.
- Water Supply = 4% of the estimated building cost
- Sanitary = 4 %
- Electrification = 9%
- Architectural Work = 1.5 %
- Contingencies = 5 %
For example, the plinth area of a Building is 120 square meters, and the plinth area rate is 2000 per square meter.
Building Cost = Plinth Area × Plinth Area Rate.
= 120 × 5000
Cost of Water Supply = 600000 × 4% = 24000.00
Cost of Sanitation = 600000 × 4% = 24000.00
Electrification = 600000 × 9% = 54000.00
Architectural Work = 600000 × 1.5% = 9000.00
Contingencies = 600000 × 5% = 30000.00
Total Cost = 741000.00
If the building plan is not set initially, make a proposal. Rooms floor area, etc., may be decided from the requirements.
For the approximate plinth area, 30 to 40% of the total area thus determined may add for circulation, walls and waste. Now, this area is multiplied by the plinth area rate to get the approximate building cost.
For storeyed buildings, we prepare plinth area estimates separately for each storey.
Approximate Plinth Area Rate of Different Buildings
|S.No.||Building Type||Plinth Area Rate |
|Plinth Area Rate|
|1||Residential Building 1-Class||5920.00||550.00|
|2||Residential Building 2-Class||5380.00||500.00|
|3||Residential Building 3-Class||4845.00||450.00|
|4||Residential Building 4-Class||4845.00||450.00|
|5||School; and College Building||5920.00||550.00|
|9||Workshop Building (Sloping Roof)||3230.00||300.00|
|10||Model Village House||2150.00||200.00|
|11||Multi storeyed Frame Building||6460.00||600.00|
- Add 8 % of Building cost for sanitary and water supply work
- Add 7 % of Building Cost for electric wiring work
- Add 4 % of building cost for electric fans, lights.
- Add 1.5 % of building cost for Architectural work
- Add 6 % of building cost for other services
- Add 3 % of building cost for contingences
- Add 8 % of building cost for supervision charges
Also, Read - Building Estimate In Excel - Importance, Preparation
It is the total area of floors between walls and comprises of floors of all rooms, including entrance hall, staircase room, verandah, store, kitchen, passage corridor bath, and WC.
In short, it is similar to the plinth area minus the area covered by the wall.
Opening like door sill is excluded in the floor area. Space covered by the wall, pilaster, pillars and other intermediate support is excluded in the floor area.
What is Carpet Area?
It is the net useful or livable floor space. It is the area where you can spread a carpet. We measure carpet area within a building between walls to the wall.
According to RERA, a carpet area is an apartment’s net usable floor space, including usable areas like the bathroom, toilet, kitchen and internal partition walls. To know more about the carpet area, visit this article. – What is Carpet Area, Built-up Area and Super Built-up Area?
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