To construct a building, first of all calculation of various areas is the necessary step. Let’s first learn about different type of areas involved in construction of a building.

Plinth Area

Under-Construction Building

Under-Construction Building

In building architecture, a plinth is the base or platform over which any building or any architectural structure is constructed. Plinth area is built up covered area of a building measured at floor level of any storey. Plinth area is calculated by taking the external dimension of the floor level excluding plinth of f-sets. If any courtyard, open areas, balconies, cantilever projections are not included in plinth area then supported porches (other than cantilevered) are included in the plinth area.

Floor Area

Floor area of a building is the total area of floor in between walls and consists of floor of all rooms, verandahs, passages, corridors, staircase room, entrance hall, kitchen, stores, bath and latrines (WCs) etc. Sills of doors and openings, walls pillars, plaster and other intermediate supports are not included in the floor area. In short floor area is equal to plinth area minus area occupied by walls, for deduction of wall area from plinth area to obtain floor level.

The floor of each storey and different types of floor should be measured and taken separately. The floor area of basement, mezzanine, barsaties, mumties, porches etc. should be measured separately.

Carpet Area

Building layout and design are vital factors to look for when constructing a home.

Building layout and design are vital factors to look for when constructing a home.

Carpet area of building is the useful area or liveable area or lettable area. This is the total floor area minus the circulation area (Verandahs, corridors, passages, lifts, entrance hall etc.) and many other non useable areas as bath, W.C., air conditioning room etc. For an office building, carpet area is the lettable area or useable area, and for residential building carpet area is the liveable area and should exclude the kitchen, pantry, stores and entrance to other rooms which are not used for living purpose.

The carpet area of an office building may be 60% to 75% of the plinth area of the building with a target of 75%. The carpet area of residential building may be 50% to 65% of the plinth area of building with a target of 65%.

For a framed structure multi-storeyed building, the area occupied by walls may be 5% to 10% of the plinth area (3% for external wall and 2% for internal walls) and for ordinary building it should be without the plinth area.

NOTE: The plinth area, floor area, circulation area, carpet area etc. should be measured or taken separately of each storey or floor.

Floor Area Ratio = Total covered area of all floor / Plot Area

Other Useful Informations

To own a comfortable home is dream of everyone.

To own a comfortable home is dream of everyone.


  • Reduction in Strength of Concrete made with Stored Cement
    Period of Storage of Cement (Month) 0 3 6 12 24
    Approx. Relative Strength (Percent) 100 80 70 60 50
  • Removal of Form Work (Shuttering)
    Sides of Foundation, Columns, Beams and Walls 2 Days
    Undersides of Slab up to 4.5 m Span 7 Days
    Undersides of Slabs above 4.5 m Span and of Beam and Arches up to 6 m Span 14 Days
  • Volume of one bag of cement is 0.03487 cum or 1.230 cubic feet
  • Measuring Box to be used to be at site (size – 35 cm x 25 cm x 40 cm)
  • Weight of a TMT Bar (Reinforcement Steel) for different diameters is given below :
    Diameter Weight Per Meter
    6 mm 0.240 Kg / meter
    8 mm 0.395 Kg / meter
    10 mm 0.616 Kg / meter
    12 mm 0.888 Kg / meter
    16 mm 1.576 Kg / meter
    20 mm 2.450 Kg / meter
    25 mm 3.867 Kg / meter
  • Consumption of Water for Building Work
    Brick Work & Concrete Work 2250 litres / cum
    Plastering Work 85 litres / sq. m
    White Washing per Coat 3 litres / sq. m
    Road Work, Metalling or Graveling (6” Thick) 130 litres / cum