Building area definitions

BUILDING AREA DEFINITIONS

Carpet Area

Carpet area is the usable area of a building. As the name suggests, carpet area means the area of the building where carpet can be laid. In a residential building, it will exclude verandah, bathrooms, staircases, etc. The carpet area of an office building can be 60 to 75% of the plinth area and in a residence, it can be as low as 50 to 65% (65% being the target to be achieved) of the plinth area.

Plinth Area

Plinth area is the built up covered area of a building measured at floor level of any storey. It is calculated by taking external dimensions of the building at floor level.

The following shall be included in the Plinth area:

(i) Total floor area of walls at the floor level excluding plinth offsets, if any.

(ii) Internal shafts for sanitary installations having area less than 2 sq.m., air conditioner ducts, lifts etc.

(iii) The area of mumty room at terrace level. (iv) Area of porches other than cantilevered.

The following shall not be included in the Plinth area:

(i) Area of loft.

(ii) Internal sanitary shafts more than 2 sq.m. in area.

(iii) Enclosed balconies, courtyard, open areas, cantilever projections etc.

(iv) Towers, sunshade, domes etc., projecting above the terrace level, not forming a storey at terrace level.

(v) Architectural bonds, cornices, etc.

(vi) Sunshades, vertical sun breakers of box louvers projecting out.

Floor Area

The floor area is the plinth area less the area of the walls. In the calculation of wall area, thickness of the wall shall be inclusive of finishing and dado if the height of such finish is more than 1 meter from floor finish.

The following shall be included in the wall area:

(i) Door and other openings in the wall

(ii) Intermediate pillars, supports or any other such obstruction within the plinth area irrespective of their location

(iii) Plaster along wall exceeding 300 sq.cm. in area

(iv) Flues which are within the wall

(v) Fire place projecting beyond the face of the wall in the living room or bed room

(vi) Built in cupboard, almirah and shelf appearing within a height of 2.2m from floor

From the above guidelines, the floor area refers to the areas of all rooms, including kitchen, store, bath room, verandah (excluding area of pillars), corridor and all such areas on plinth excluding the area of walls, area of door sills and structuring which occupy any area on plinth.

The area of the basement, floor without cladding (slitted floor), and floors including the top floor which may be partly covered (Barsati), mezzanine floor and garage shall be measured separately.

Floor Space Index

Floor Area Ratio is commonly known as the Floor Space Index (FSI) and is given by

FSI of a flat = Total Covered Area (Pinch Area) of all the floors / Total Plot Area of the Building

An FSI of 1.5 is nowadays allowed for flats in most cities. This means, the total Plinth Area shall not exceed 1.5 times the Plot area in which the construction takes place.

Circulation area

Circulation area is the floor area of verandah, passages, staircase, balconies etc. which are used for movement of persons using the building. Thę circulation area of any floor comprises of the following:

(i) Verandah

(ii) Balconies

(iii) Passages and corridors

(iv) Entrance hall

(v) Staircase and mumties

(vi) Shafts for lifts

(vii) Porches

The circulation area may be divided into two parts:

Horizontal circulation area: It is the area required for horizontal movement of the users of the building, such as verandahs, corridors, balconies, porches etc. This may be 10% to 15% of the plinth area of the building.

Vertical circulation area: It is the area or space occupied by staircase, lifts, and the entrance hall adjacent to them required for vertical movement of the users of the building. This may be 4% to 5% of the plinth area of the building.