Will upward revision of FSI help?

A very good article

A major issue: The question of Floor Space Index has assumed importance now.

Should the Floor Space Index (FSI) for buildings be increased or not? This question has assumed importance in the last few weeks following the report that the government is considering an upward revision of the FSI.

The debate has come about for two reasons. One, the draft second master plan in its building rules has not recommended any rise in FSI and so has the expert committee that was consulted by the CMDA. The other reason is that it appears that Chennai has a low FSI while cities like New York have 10. If the city has to attract more investment and apartments have to be made affordable it is necessary to raise the FSI, the supporters argue. While those who oppose state that the land price is not connected to FSI but is more related to demand and speculation. The very fact that the Chennai land price is more than Bangalore, in spite of low FSI, proves the point, they argue

Why important?

FSI is the parameter that determines how much one can build in a given plot. For example, if you have a 2400 sq.ft plot then in Chennai with an FSI of 1.5 you can build 3,600 sq.ft. The planning experts study the existing density of the city and find out how much more a city can hold with respect to the infrastructure that is available and determine the FSI. They also use this control to regulate development and future density of the city. In Chennai while normal buildings have a 1.5, multi-storeyed buildings can go up to 2.5 and if it is IT building up to 3.75.

How does this number affect the economics of real estate? For example, if you have a land priced at Rs.50 lakh per ground (2400 sq.ft) or Rs 2,083 per square feet and the FSI is 1.5. Then you need 0.65 square feet of land (1/1.5) for constructing one square feet of building. The land cost per square feet would be Rs.1355 per sq.ft. If the construction cost is Rs.1,500 and other incidentals Rs.300 then the total cost of the apartment would be Rs.3155. However, the final sale price will depend on the profit margins and other incidentals added by the developer. In this case, if the FSI is not 1.5 but say 2.5, then the land cost would Rs.835 per square feet and the total cost of the apartment should be only Rs. 2635. If we use the same logic then with an FSI of 10 we should have the apartment cost at Rs.2008. The question is, will the market sell the apartment at such low price with the increase in FSI?

If we go by studies done on cities like New York this will not happen. One economist observed that if we hypothetically assume that all buildings in Manhattan are allowed to increase by another hundred floors the price would at the most come down by 15 per cent and not more. The price of an apartment is not a simple factor of FSI and it has other externalities such as demand, speculation, investment potential and other factors. Even closer home, Hyderabad and Bangalore are no cheaper just because they have a higher FSI. Hence the price argument for higher FSI will not deliver the benefits to consumers especially the middle and low-income buyers.

Density and size of the city are two key issues that seem to determine the FSI. Chennai city has a density of 24,681 persons per square km. Mumbai has a density of 27,715 persons per square km and Delhi with a density of about 19, 658. All the three cities have high densities. It is not surprising all the there cities have low FSI – Mumbai with 1.33 and Delhi with 1.5 to 1.2 for bigger plots and 3.5 for smaller plots. In Bangalore, where the FSI is 3.5, the density is 11,000 persons per sq. km. Even here, higher FSI is permitted only in roads that are 30 m wide. Manhattan, with an average residential FSI of 10, has a density of 26,776 persons per square km. Chennai iyt looks, with a low FSI is close to it. In other words, Chennai is efficient in terms of utilisation of land and not what many try to make of it. The differences between the two cities are in plot sizes and apartment or unit sizes and the height.

Two ways of growth

There are two models for a city to grow. One it can be low rise but with high density and the other is to go high-rise and high density. What cities like Chennai have chosen is the low-rise model without compromising on high density. The city is compact and not a sprawl. It is also important to know that the maintenance cost of the buildings increases with the height. Secondly tall buildings need not necessarily be a preferred form for all sections of people.

Cities can have different FSIs and even within the city the FSI can vary from zone to zone. But this cannot come out of a simple comparison of FSI numbers across cities nor can it be decided on thin ideas of city image. FSI affects the quality of life significantly and has to be worked out based on careful study. Matching levels of infrastructure should support any modification.
Source: The hindu


  1. Can the Tamil Nadu Housing Board’s HIG residential building (blocks of 6 and 12 houses) be considered as a multi-storey building. During recontruction of the old TNHB flats will the FSI of 3.5 be applicable?

  2. Arun Oommen

    Can anybody tell me the FSI in private apartments in Chennai with 30M road.

  3. sathish

    Shall we consider Individual house (three floor ) as multi-storeyed buildings for FSI exemption

  4. nagmachi

    What is the benefit as a buyer ?? anyway the Undivided share of land (In case of apartment) is going to be low…. which in turn neutralize the decrease in flat rate….


  6. K. Saravanan

    Can the Tamil Nadu Housing Board’s MIG residential building (blocks of 12 houses) be considered as a multi-storey building. During reconstruction of the old TNHB flats will the FSI of 2.5 be applicable (located in ambattur industrial-vavin road opp to dav boysschool.

  7. siva

    what is fsi for building a residential house abuting 20ft road

  8. siva

    pl let me know the fsi for building a residential house abuting 20ft road

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