Apartment Related IssuesBuilding Plan ApprovalCMDA/DTCPReal Estate Updates


Floor Space Index or FSI


Floor Space Index or FSI for Residential Buildings increased from 1.5 to 2 by a GO. The increase applies to both CMDA and DTCP areas. This GOs amended the relevant Sections/Rules of the Development Rules and Development Control Rules.
The Government should address the set-back spaces and road width issues first. Then only these amendments will benefit the small plot owners. The proposed Combined Development Rules 2018 (CDR) may take care of this.
The government is yet to notify the Draft CDR. (10/10/2018)
The draft CDR attempts to bring uniformity to regulations for realty developments, in the entire Tamilnadu.
Now, there are three categories for buildings. They are ordinary, special and multi-storeyed buildings. The new CDR aims to trim them into two categories: High rises and non-high reises. High rises are Constructions that are higher than six storeys (stilt + five floors) and exceed the height of 17.25m. Non-high rises are those below these parameters.
Now, by the GOs, the FSI is increased to 2, across the State amending the DR and DCR.
Also, more proposals are on the anvil suggesting more changes. They are in the Set-back spaces, Exemptions from FSI Norms, Road width criteria etc.
We wrote this earlier, based on the hitherto existing Development Rules. We will Revise it after the notification of Combined Rules.

Floor Space Index

Floor Space Index or FSI is a tool to regulate building construction activities. Development Regulations(DR) provide detailed guidelines about FSI.

The orderly growth of Urbanisation is the aim of Development Regulations.

For the Chennai Metropolitan Area, the CMDA frames the Development Regulations. The Floor Space Index-FSI- is now defined and detailed in the DR of the Second Master Plan.

Definition of FSI

The DR 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 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 one understand the most 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.
The plan submitted should be as per the Development Regulations (DR) for that area. Only then the Plan Permission will be granted.

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. They are 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

This is about Ordinary Buildings, in Primary Residential Zones of Chennai Metropolitan Areas (CMA)
The FSI for these Ordinary Buildings is 2(as per the amended Rules). This means the total Plinth Area must 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 Coverage  
2. Set backspace
3. Abutting Road width etc.
Plot Coverage
At the ground floor, the constructed area coverage must 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 open space which is essential for air, natural light and safe in times of emergencies.
 Front, side and rear setback space must be allowed as per the Regulations. The details vary according to the dimensions of the Plot.
Height of the building
Must not exceed 1.5 times the width of the road or most of 9 meters
In view of these restrictions on the calculation of the FSI, often it may not be possible to Achieve the permissible FSI.

Exemptions from FSI Norms

There are some exemptions in the DR. These are detailed in the DR that are not taken into account while calculating the FSI. They are:

ANNEXURE XVIII [DR No. 2(21)& 2(34)] Spaces excluded from FSI and Coverage Computation 
1 The following must not be counted towards FSI and plot coverage computation:
(1) Areas covered by staircase rooms and lift rooms. Passages thereto above the topmost storey, architectural features, chimneys, elevated tanks (provided its height below the tank from the floor does not exceed 1.5 metres.) 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) Fire escape area, staircases and cantilever fire escape passages. 
(5) Basement area, floor/floors used for parking 
(6) Stilt parking floor area, provided its clear height (between the 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) Service ducts area , and garbage shaft.
(9) Balcony / Service verandah area to an extent of 5 per cent of each dwelling unit area in case of residential buildings and 5 per cent 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 most of 10 per cent 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 bathroom and water closet (not exceeding 20 sq.m.) for  each block in cases of special buildings, Group development, and Multi storeyed Building at ground floor /stilt parking floor 
(c) Gymnasium of 150 sq.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 the basement floor or ground floor or stilt floor.      
     (vii) Lumber room in the basement floor or ground floor.      
     (viii) AHU on all the floors.      
     (ix) Electrical /switchgear rooms on all the floors.
(e) Separate letterboxes area of one room in the ground floor of residential and commercial Multi storeyed building, Special buildings, Group developments.

Achievable FSI Affects Value of the Property

The market value of properties of the same size, in the same locality with different abutting Road Width, will differ. 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. This means more income by way of increased Floor Area that can be constructed and sold.
For example, consider a Construction in a big land parcel of say 100 acres on a narrow Road of say 15′. Here, Construction can rise up to a most of 22.5′ which is enough for putting up a Ground+1 structure only. Since the total constructed area is low, the profitability from the construction venture will also be low. So, the price the Land will fetch also will be low.


Why Premium FSI?

Premium FSI is a tool to encourage vertical growth in a metropolis. In a city like Chennai, every inch of space counts. Premium FSI will allow construction of more floor area. This will ease the pressure on land at least to a small extent.

CMDA Guidelines 
Regulation 36 of the Development Regulations of Second Master Plan, provides for allowing Premium FSI. subject to the condition that the most Premium FSI allowed will be 1.
The details of Road Width and corresponding Premium FSI allowable under the Regulations are as under:
  1. Road Width 18 Meters and above(60′ and above -Premium FSI- 40% of normally allowable FSI
  1. Road Width between 12 Meters and 18 Meters (Between 40′ and 60′)-Premium FSI: 30% of normally allowable FSI
  1.  Road Width between 9 Meters and 12 Meters- Premium FSI : 20% of normally allowable FSI
(The other conditions for computing FSI/Premium FSI to be taken into account are:
Setback Space, Road Width, Plot Coverage, Height of the building etc .)

Premium FSI Charges

The CMDA Rules on Premium FSI charges are given below:
Extra benefit by way of Premium FSI accrued to the developer is related to the proportionate land extent.
For example,-
a)Where permissible FSI is 1.50-
for every 1 sq.m extra floor area constructed availing Premium FSI, proportionate land required will be 2/3 or 0.66 sq.m
b)Where permissible FSI is 2.0 to 2.50-
for every 1 sq.m.of extra floor area constructed availing premium FSI, proportionate land required will be 1/2 or 0.50 sq.m., to 2/5 or 0.40 sq.m.
The amount to be paid by the applicant towards the Premium FSI is Premium FSI Charge. This will be equal to the cost of the proportionate land stated above. The cost of Land is as per the Guide Line Value of the Registration Department.
The applicant must remit the Premium FSI Charge in one lump sum. This is before getting planning permission.
All the amounts collected towards the award of Premium FSI must be remitted into the specified Government account. The will be utilised for infrastructure development of the area.
Impact of Guideline Value Revision on Availing Premium FSI

n 2017 the Government revised the Guideline Values. Now the Guideline Values are much lower than earlier. The Premium FSI charges are to be paid as per the Guide Line Value only, which is beneficial to the Promoters.

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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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