Apartments Related IssuesBuilding Plan ApprovalCMDA/DTCPReal Estate Updates




Tamilnadu Government has issued GOs increasing the FSI for Residential Buildings from 1.5 to 2. This increase is applicable for both CMDA and DTCP areas. By these GOs, the relevent Sections/Rules of the Development Rules and Development Control Rules have been amended. 

Small Plot owners will be benefited by these amendments, only when the set back space and road width issues are addressed. That is expected to be done in the proposed Combined Development Rules.

The Draft Combined Development Rules announced by the Government of Tamilnadu has not been Notified yet.(10/10/2018)

The draft Tamil Nadu Combined Development Regulation and Building Rules, 2018, attempts to bring regulations for realty developments from Thiruthani  to Kanyakumari Dist, under a single umbrella.

Briefly, as per the draft rules, the existing classification of ordinary, special and multi-storeyed buildings has been trimmed to two categories. Constructions that are higher than six storeys (stilt + five floors) and exceed the height of 17.25m, have been classified as high-rises, and those below these parameters, would be identified as non-high rise buildings. 

Now, the FSI has been increased to 2, across the State by GOs, amending the DR and DCR.

Also, some more changes in the Setback spaces, Exemptions from FSI Norms, Road width criteria.. have been proposed. 

The following article is written earlier, based on the existing Development Rules.We shall Revise it once the Combined Rules are Notified.


Floor Space Index

Development Regulations (DR) are framed to control and regulate Developments and to help orderly growth of urbanisation.

For the Chennai Metropolitan Area, the DR has been framed by the CMDA. The Floor Space Index-FSI- is now defined and detailed in the DR of the Second Master Plan

FSI, is one of the methods under the Rules/Regulations by which the Plan Sanctioning Bodies control building construction activities. 

Definition of FSI

The Development Regulations of the Second Master Plan for Chennai, defines Floor Space Index      as under:

Floor Space Index (FSI) means the quotient obtained by dividing the total covered area (plinth) on all floors except the areas specifically exempted under these regulations (given in Annexure XVIII) by the plot area which includes part of the site used as exclusive passage. FSI = Total covered area on all floors/Plot area

In other words,FSI is the ratio of the Plinth area in a Project to the Land Area. It helps you understand the maximum extent of the Floor area that could be constructed in a Space (Plot).

Building Plan Permission

Before starting any construction activity, one has to apply for Building Plan Permission from the concerned Local body, and the Plan Permission will be granted only if the plan submitted is as per the Development Regulations (DR) for that area. Since FSI is part of the Regulations and Rules, the Plan should conform to the norms set out there.

Classification of Buildings, Land Use Zones, and FSI

Buildings are generally classified into

Ordinary buildings -less than 30’ height,

Special Buildings -less than 50’ height and

 Multi-Storeyed Buildings- above 50’.

All lands are categorised into 10 Zones, like Primary Residential Zones, Mixed Residential Zones,  Commercial Zones etc.

The FSI is different for different class of building, and for different land use areas.

FSI for Ordinary Buildings

We are concerned here with the Ordinary Buildings in Chennai Metropolitan Areas (CMA)  in Primary Residential Zones.The FSI for these Ordinary Buildings is 2(as per the amended Rules). This means, the total Plinth Area shall not exceed 2 times the Plot area in which the construction takes place. To arrive at the Floor Area that could be constructed, the calculation must also take into account the following: 1.       Plot Coverage2.       Set back space

3.       Abutting Road width etc.

Plot Coverage: At the ground floor, the constructed area coverage shall not exceed 70% of the Land area. This means the entire construction, though within the norms should not be done to cover the entire plot. This ensures opens space which is essential for air, natural light and safe in times of emergencies.

Setback space: Front, side and rear setback space shall be allowed as per the Regulations. The details vary according to the dimensions of the Plot.

Height of the building: Shall not exceed 1.5 times the width of the road or a maximum of 9 meters

In view of these restrictions on calculation of the FSI, in many cases it may not be possible to Achieve the permissible FSI.

Exemptions from FSI Norms

There are some exemptions, however, that are detailed in the Regulations that are not taken into account while calculating the FSI. They are:

[DR No. 2(21)& 2(34)]Spaces excluded from FSI and Coverage Computation
1 The following shall not be counted towards FSI and plot coverage computation:
(1) Areas covered by staircase rooms and lift rooms and passages thereto above the
top most storey, architectural features, chimneys, elevated tanks (provided its
height below the tank from the floor does not exceed 1.5 metre.) and WC (area
not exceeding 10 sq.m)
(2) Staircase and lift rooms and passage thereto in the stilt parking floor
(3) Lift wells in all the floors
(4) Area of fire escape staircases and cantilever fire escape passages.
(5) Area of the basement floor / floors used for parking
(6) Area of the stilt parking floor provided its clear height (between lower floor and
the bottom of the roof beam) does not exceed 3.0m and it is open on sides, and
used for parking
(7) Area of structures exclusively for, accommodating machineries for water
treatment plant and effluent treatment plant proposed with clearance from Tamil
Nadu Pollution control Board,
(8) Areas covered by service ducts, and garbage shaft.
(9) Area of Balcony / Service verandah to an extent of 5 percent of each dwelling
unit area in case of residential buildings and 5 percent of room area in the case
of hotels and lodges.
(10) Porches /Canopies / porticos
(11) Service floor with height not exceeding 1.5 metres
(12) The following services and incidental structures necessary to the principal use
subject to a maximum of 10 percent of the total floor area.
(a) Area of one office room not exceeding 15 sq.m for co-operative housing
society or apartment/ building owners association in each block
(b) Servant’s/drivers bath room and water closet (not exceeding 20 sq.m.) for  each block in cases of special building, Group development, and Multistoreyed Building at ground floor /stilt parking floor (c) Gymnasium of 150sq.m in floor area
(d) Area covered by
      (i) Metre room in Ground floor or stilt parking floor
     (ii) Air-conditioning plant room in basement or ground floor
     (iii) Electrical room (conforming to Annexure XXIV) in Ground floor or Stilt parking floor
     (iv) Watchmen or caretaker booth/room in Ground floor / Stilt parking floor
     (v) Pump room in Ground floor or stilt parking floor.
     (vi) Generator room in basement floor or ground floor or stilt floor.
     (vii) Lumber room in basement floor or ground floor.
     (viii) AHU in all the floors.
     (ix) Electrical /switch gear rooms in all the floors.
(e) Area of one room in ground floor of residential and commercial Multistoreyed
building, Special buildings, Group developments for separate

Violation of these Rules may invite penal actions that may include demolition.

Achievable FSI Affects Value of the Property

The market value of properties of almost same size in the same locality with different Abutting Road Width, will differ widely. Higher the Abutting Road Width, higher the rate the property will fetch. This is so because, higher FSI could be achieved in a property having wider Abutting Road Width, which in turn means more income by way of increased Floor Area that can be constructed and sold.

For example, a Construction in a big  land parcel of say 100 acres on a narrow Road of say 15′, can  rise up to a maximum of 22.5′ which is enough for putting up a Ground+1 structure only. With the total constructed area being low, the possibility of commercially exploiting the land are low, and so the price it will fetch also will be low.

-Chennai Realties


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6 thoughts on “FLOOR SPACE INDEX Chennai

  1. Sir, I am having a breadth of 22 feet and 100ft in length. Could you suggest the best possible area to utilize the ground floor, first floor and second with setbacks. As my plot breadth is very small how can I arrive the setback area. Please explain.

  2. Sir…The new building rules doesn’t say anything about exclusion of balcony for FSI calculation

  3. G.Sankaran i am having 2500 SQ.Ft with breath of 35 feet and length in 70 feet road. what current fsi limit for residendial building construction

  4. my aunty having land of 3600 sqft at ramakrishna st, next to sai baba mandir, perambur, the road width is 33 feet, what is the fsi now at present if she goes for construction, upto how many floors, please reply

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