Requirements for building plan approval - When planning buildings in cities, towns and municipalities in India, we have to obey certain rules and regulations regarding the minimum size of the plot with respect to the width of the road in front, spaces to be left around the building for ventilation, etc. In this chapter, we will briefly examine the nature of these requirements that are laid down. As these requirements vary from place to place in the same city and from city to town, only the basic principles are discussed in this chapter. For the rules applicable to each situation, the regulations published by the concerned authority (panchayat, municipality or corporation) should be consulted.
CLASSIFICATION OF BUILDINGS
According
to the National Building Code of India (1970), buildings are classified into 9
groups according to their occupancy as follows:
(i) Group
A: Residential buildings
(ii) Group
B: Educational buildings
(iii) Group
C: Institutional buildings
(iv) Group
D: Assembly buildings
(v) Group
E: Business buildings
(vi) Group
F: Mercantile buildings (whole and retail)
(vii) Group
G: Industrial buildings (with fire hazards)
(viii)
Group H: Storage buildings
(ix) Group I: Hazardous buildings
These names are self-explanatory.
There are many subdivisions in each of these groups. For example, Group A
(residential) buildings can be further subdivided into private family residences,
dormitories, hostels, etc. However, we will not go into these details as they
are to be studied under Architectural Planning Requirements. The architect has
to plan buildings according to these regulations. These requirements can be
obtained from the office of the concerned metropolitan authority or
municipality.
SOME DEFINITIONS
There are some definitions
with which we must be familiar.
Building Line
A building line is the line
corresponding to the plinth of a building that adjoins the street or extension
of the street. According to regulations, there is a minimum distance we have to
keep between this line and the adjoining street line.
Building Height
Generally speaking, the height
of a building is its height above the ground level. However, in some municipal
regulations, it is measured with reference to the middle of the adjacent road
level. In cases of buildings abutting a street, heights are measured
differently for a flat roof construction from that of sloped roof
construction.
For a flat roof construction
adjoining a street, the height is defined as the vertical distance measured
from the average level of the centre line of the adjoining street to the
highest point of the roof of the building.
For a sloped roof without
gables adjoining a street, the height is taken as the vertical distance
measured from the average level of the centre line of the adjacent street to the
point where the external surface of the outer wall intersects the finished
surface of the sloping roof.
For a gabled roof, the
reference point for height on the building is the mid-point between the eave
level and the ridge.
Notes
(a) According to the official
criteria of the Council of Tall Buildings and Urban Habitat, "The height
of a building is measured from the sidewalk level of the main entrance to the
architectural top of the building, including the penthouse and tower. Towers
include spires and pinnacles. Television and radio antennas and flag poles are
not included. Presently, the tallest building in the world is the 508 m high
Taipei in Taiwan. Petronas Tower in Malaysia is 452 m high.
(b) The definition of height
is important as many corporations classify a building as high and low rise
depending on its height. The taxes to be paid for construction permits are
different for low and high rise buildings. There are case histories where
disputes have arisen with sloped roof buildings regarding their heights.
(c) The so-called 63-1/2 degrees rule
refers to a diagonal drawn at 63 1/2° to a horizontal line drawn with reference
to the rear boundary of the building as shown in Fig. below. No part of the
building is to project beyond this diagonal.
Multistorey Buildings (MSBs)
Buildings more than four
floors (ground plus three or stilts plus four) or more than 15 m in height are
called multistorey buildings. These can be built only in a plot area
not less than 1500 sq m (6.725 grounds in Tamil Nadu).
Carpet Area
This is the usable area of a
building. In a residential house, 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
This is the built-up covered
area of a building measured at the floor level by taking the external
dimensions of the building excluding the plinth offset. It also includes areas
of porches (other than cantilevered) balconies, etc.
Floor Area
It is the plinth area minus
the area occupied by walls, doors, openings, etc.
Floor Area Ratio (FAR) or Floor Space
Index (FSI)
It is commonly known as the
floor space index (FSI) and is given by
An FSI of 1.5 is nowadays
allowed for flats in most cities (MSBs require more).
Front Setback (FSB), Rear Setback (RSB) and Side Setback
(SSB)
These are the setbacks specified by the competent authority
from the boundaries of the building plot.
The minimum front setback (FSB) to be kept when planning a
building will be specified with reference to the area where the building is
situated and also the width of a road in front. In many old congested
commercial areas of cities, it is usually less than that specified for new
developing residential areas. The minimum RSB and SSB are usually specified
with reference to the height of the building and the width of the road in front.
EXAMPLE OF BUILDING REGULATIONS
As we have already seen that the building regulations vary
from state to state and in the same state, from towns to cities and in the same
city, from place to place. For example, the regulations at the heart of an old
commercial area will be different from the regulations for the new residential
area in the same city. As an example, the present regulations for residential
buildings in the municipal and township areas of Chennai issued by the Madras
Metropolitan Development Authority are as shown in the table below
Requirements
in the city areas for residences G + 1 floor (Maximum for accommodating three
dwellings)
The Madras Metropolitan Development Authority has also
issued requirements separately for different types of buildings for different
areas as given below:
1. Residential (G + 1) and maximum of 3 dwelling units
2. Commercial (G + 1), not exceeding 300 m2 floor area
3. Institutional, not exceeding 4 floors or 15 m height
4. Industrial, not exceeding 4 floors or 15 m height
5. Theatres/hotels/lodges/religious buildings/Kalyana Mandapams/hospitals,
not exceeding 4 floors or 15 m in height
6. Residential layouts
7. Special buildings and group developments
These
publications can be obtained from the authority and should be consulted when
planning new buildings at a given place.
OTHER REGULATIONS
The National Building Code (SP
7-2005) and other agencies have laid down many other minimum requirements such
as a minimum number of rooms, the height of rooms, etc. for different types of
buildings. These requirements are many, but most normal building practices that
we usually follow will satisfy them.
The rules regarding boundary
walls and distance from electric supply lines which we have to comply within
cities are briefly discussed below.
Boundary walls. Normally the
height of a solid boundary wall should be limited to 1.5 m (5 ft). It can also be
2.4 m (8 ft) provided the top 0.9 m (3 ft) is of open type of wall construction
approved by the authority. In the case of corner plots for a distance of 10 m, the
solid wall height should only be up to 0.75 m and the balance should be open
type construction.
Distance from the electric
lines. The minimum safe distances for various supply voltages specified by the
Indian Electricity Supply rules are shown in the Table Below.
A minimum safe distance of building from the electricity supply line
There are many other requirements and these are to be
studied in the architectural planning of buildings.
CONCLUSION
There are many regulations laid down by the competent
authorities with regard to the location of a building at a given site. Building
plans will be "approved for construction" only if these requirements
are met. In addition, before starting the actual construction of buildings, we
should also go to the site and physically check these requirements from the
approved construction drawings. There will be no difficulty getting a completion report from the authority after the building has been completed.
There are many case histories where this omission of checking at the site
before construction has led to difficulties after completion of the building.
FAQ
What are development control regulations?
It is a mechanism that controls the growth and use of land.
This includes constructing new buildings, extending existing buildings and
converting the building or land to another use.
What is the 63-1/2 degrees angle rule?
The so-called 63-1/2 degrees rule refers
to a diagonal drawn at 63 1/2° to a horizontal line drawn with reference to the
rear boundary of the building as shown in Fig. above No part of the building is
to project beyond this diagonal.
Is building plan approval mandatory in Tamilnadu?
Yes, Planning permission is required in both plan and
non-plan areas. Section 47 (A) of the Town and Country Planning Act 1971
How building plans are approved?
Building approval includes the building plan and layout
approval for the building. building plans are approved by obtaining the approval of the Authority for
Building plan approval/building permits under the provisions of the Building byelaws,
Master Plan and Local Bodies Acts.
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