Definitions of some of the terms commonly used in Building Construction

Definitions of some of the terms commonly used are as follows.

1. Building. Any structure for whatsoever purpose and of whatsoever materials constructed, and every part the weather used for human habitation or for any other purpose is known as a building. The building consists of a foundation, plinth, walls, floors, roofs, verandah, balcony, projections, chimneys, plumbing, and building services. Tents and shelters are not considered buildings.

2. Building Height. In the case of flat roofs, the vertical distance measured from the average level of the centerline of the adjoining street to the highest point of the building is known as its height. In the case of pitched roofs building height is the vertical distance measured from the average level of the centerline of the adjoining street to the point where the external surface of the outer wall intersects the finished surface of the sloping roof. In the case of gables facing the road, it is the vertical distance measured from the average level of the centerline of the adjoining street to the mid-point between the eaves level and the ridge. If the building does not abut on a street the height shall be measured above the average level of the ground around and contiguous to the building. If some architectural features which serve no other purpose except that of decoration, shall not be considered for the purpose of taking heights.

3. Building line. The line up to which the plinth of the building adjoining a street or on the extension of a street or on a future street may lawfully extend is known as the building line. The line refers to the line of building frontage. Often this line is known as set back or front building line. Generally, the buildings are allowed to be constructed beyond the building line. But certain buildings such as cinemas, factories, commercial concerns which attract a large number of vehicles should be set back a further distance apart from the building line. The line up to which such buildings can be constructed is known as a control line. This line is set further deep from the building line. The distance of the control line from the center of the adjoining street or road may be about one and half times that of the building line.

The distances of lines of building frontages are decided by the category of the city zone in which the site of the proposed building is located.

Town planning authorities mark the present width and future likely widening of each street and road. The minimum distance from the centerline of the road is prescribed for the line of building frontages. Sometimes, there is a line to which generally all the buildings abut. This line is known as the 'general building line'. No building is allowed to be extended beyond this line.

However, the rule of the general building line is released if the general line existing buildings is too deep or more than 15 m from the roadway. The setback obtained by the building line proves helpful in

(i) future widening of the road

(ii) reducing noise, dust from abutting buildings,

(iii) Preventing the creation of blind corners at the intersection of streets and

(iv) maintaining open spaces for air, sun, etc.

4. Permit. Permission or authorization in writing by the authority to carry out work regulated by the code is known as the permit.

5. Set backline. The set backline is a line usually parallel to the plot boundaries and laid down in each case by the authority beyond which nothing can be constructed towards the site boundaries.

6. Service Road. It is a road or lane provided at the rear or side of a plot. It is used mostly for service purposes.

7. Street line. It is the line defining the side limits of a street.

8. Street. It is any highway, street, lane, pathway, alley, carriageway, footway; which may be thoroughfare or not, the public has a rite of passage or access to it. It includes channel ditches, stormwater drains, culverts, sidewalks, traffic islands, roadside trees, railings, and barriers within the street lines.

9. Sanctioned plan. It is a set of drawings, plan, and specifications submitted under the code and duly approved and sanctioned by the authority.

10. Street level or grade. It is the officially established elevation or grade of the center of the street upon which the plot fronts. If there is no officially established grade the existing grade of the street at its mid-point is taken as the street level or grade.

11 Room height. The vertical distance measured from the finished floor surface to the finished ceiling surface is known as the room height. Where a finished ceiling is

provided. the underside of the joists or beams or tie beams shall be taken as the upper point of measurement.

12. Covered area. The area covered by building immediately above the plinth level i.e., ground floor, is known as a covered area. The covered area does not include the spaces covered by

(i) Compound walls, gate, nonstories porch, and portico, uncovered staircases and area

covered by a sunshade and the like.

(ii) Garden, rockery, well and well structures, plant nursery, water pool, uncovered swimming pool, platform around a tree, tank, bench with open top and unenclosed on sides by walls and the like.

(iii) drainage culvert, conduit, catch pit, gulley pit, chamber, gutter etc.

In short, the covered area of the building is equal to the plot area minus the area due for open spaces.

13. Sunshade It is a sloping or horizontal structural overhang that is usually provided over openings in external walls. Its purpose is to provide protection from the sun and rain.

14. Balcony. It is a horizontal projection that is used to serve as the passage or sitting out place. It includes a handrail or balustrade also.

15. Basement or cellar, the lower story of a building below or partly below ground level is known as basement or cellar. It is said that at least 1.5 m of its total height should be below ground level.

16. Detached building. It is a building whose walls and roofs are independent of any other building. It has open spaces on all the sides as specified. It may include amenities such as a garden, swimming pool badminton court, etc. A detached building if meant for residence and is the highest form or class of residence.

17. Semi-detached building. A building detached on three sides with specified open spaces is known as semi-detached building.

18. Drain. It is a pipeline meant for the drainage of a building or a number of buildings or yards appurtenant to the buildings. The drain includes open channels also used for conveying surface water. Fittings like main holes, inspection chambers, traps, gullies. floor traps, etc. are also included in this term.

19. Exit. It is a means of egress from any building, story, or floor area, to a street or other open space of safety. It may be in form of passage or channel.

20 Plinth area. It is the built-up covered area measured at the floor level of the basement or of any story.

21 Plinth. The portion of a structure lying between the surface of the surrounding ground and the surface of the floor immediately above the ground is known as a plinth.

22 Open space. It is an area forming an integral part of the plot, left open to the sky is known as the open space.

23. Floor area. It means a usable covered area of a building at any floor level.

24. Floor Area Ratio (FAR). It is the quotient obtained by dividing the total covered area (plinth area) on all the floors multiplied by 100, by the area of the plot.

TAD - Total covered area of all floor X 100

Plot area the limitation of area and height of buildings of different types of construction and occupancy class are achieved by specifying it in terms of FAR.

25. Occupancy or use group. It represents the main purpose for which a building or a part of the building is used or intended to be used. Occupancy classification of buildings as specified by bye-laws is:


(i) Residential

(ii) Educational

(iii) Institutional

(iv) Assembly

(v) Business

(vi) Mercantile

(vii) Industrial

(viii) Storage and

(ix) Hazardous.


26. Story. The portion of a building lying between the surface of any floor and the surface of the floor next above it is known as a story. If there is no other floor above it, then the space between any floor and the ceiling next above it is known as a story.

27. Raw housing. It is a row of residential houses. Every house has only the front, rear, and interior open spaces. Such houses do not have any open spaces at the sides.

28. Plot or site. It is a piece of land enclosed by definite boundaries. When the site lies at the junction of and fronting on two or more intersecting streets it is called a corner site. Site access to which is by a passage from a street whether such passage forms part of the site or and rear site boundaries is known as depth of the site. A site having a frontage on two streets other than a corner plot is known as a double frontage site.

29. Ledge. It is a shelf-like projection within a room. It may be supported in any manner whatsoever except by means of vertical supports. Its projection must not be wider than 1 m.

30. Loft. It is an intermediate floor between two floors with a maximum height of 1.5 m. It is constructed for storage purposes.

21 Mezzanine floors. It is an intermediate floor between two floors in any story. overhanging or overlooking a floor beneath. The area of the mezzanine floor is restricted to the area of that floor. Its maximum height has to be 2.2 m.

32. Dwelling house. The term dwelling house is used to indicate a residential building which includes an outhouse, and garage for parking,

33. Dwelling unit. This term is used to refer a residential accommodation for one

family with maximum requirements as one living room, one kitchen, one bathroom, and one latrine.

34. Tenement: A building that is to be used as a dwelling unit for a family is known as a tenement.

35. Tenement buildings: This is a residential building constructed in the detached or semidetached manner by a society, public trust, or any authority established by law in India, in a building plot each being designed and constructed for separate occupation with independent provisions for bathroom, toilet, etc.

36. Ownership tenement flats: These are residential flats constructed in a detached or semi-detached manner on plinth or pillars by a society, a public trust, or any authority established by law in India. for separate ownership and with the provision of an independent bath, latrine, and a common staircase.

37. Low rise and high-rise buildings: The buildings having not more than two floors excluding the ground floor are known as low rise buildings and the buildings having more than two floors excluding the ground floor are known as high-rise buildings.

38. Building unit: This term is used to indicate a final plot or a part of a final plot or the combination of more than one final plot as approved by the concerned local authority.

39. Auditorium: It represents enclosures, covered or open, where people can assemble for watching a performance given on the stage or screen.

40. Window: It is an opening to the outside other than a door which provides all or part of the required natural light or ventilation or both to an interior space.

41. Yard: Yard is an open space at ground level between a building and the adjoining boundary lines of the plot unoccupied and unobstructed except by encroachments or structures specifically permitted by these bye-laws on the same plot with a building. All yard measurements shall be the minimum distance between the front, rear and side plot boundaries and the nearest point of the building including enclosed or covered porches. Every part of every yard shall be accessible from every other part of the same yard.

(i) Front yard. It is a yard extending across the front of a plot between the side yard lines. It is the minimum horizontal distance between the street line and the main building or any projection thereof, other than steps, unclosed balconies, and on porches.

(ii) Rear yard. It is a yard extending across the rear of a plot measured between plot boundaries. It is the minimum horizontal distance between the rear plot boundary

And the rear plot boundary and the building or any projection other than steps, unenclosed balconies, or unenclosed porches. In a corner plot, the rear yard shall be considered as parallel to the street non which the plot has its least dimensions. In both the corner and interior plots, the shall be at the opposite end of the plot from the front yard.

the rear yard

(iii) Side yard. It is a yard between the building and the side line of the plot. It extends from the front line to the rear line of the plot. It is the minimum horizontal distance

between a side boundary line and the sides of the building or any other projections other than steps, unenclosed balconies, or unenclosed porches.

42. Rain or Rent-house. It is a covered space open at least on one side. It is constructed on a terraced roof and mainly used for shelter during rains.

43. Habitable Room. It is a room occupied or designed for occupancy by one or more persons for study, living, sleeping, eating, kitchen, etc. It does not include the W.C. bathroom, corridors, cellars, etc.

44. Staircase room It is a cabin-like structure with a covering roof over a staircase and landing. It encloses only stairs and not used for human habitation.

45. Set back. It is also referred to as a building line. Set the back may be defined as frontage margin or open space in front of the abutting street or road.

The land contained in the setback belongs to the owner of the property. But he is prohibited from putting any structure in the setback portion. The width of the setback depends upon the area in which the plot is located. The size of the plot also determines the width of the setback. In connection with the light plane, the horizontal distance to be left from the vertical face of the building is also known as set-back.

46. Light plane. In the city area as it is known, the construction is allowed on the full area without the provision of margins on any side. In such cases, it becomes necessary to check that the height of one building does not obstruct the ventilation of the property on the other side of the road. For this purpose, a light plane is marked at a suitable angle from the edge of the road on the other side and the height of the building is suitably curtailed off to allow the light plane to pass. The angle of the light plane is 45° or 63-50°, the latter being very common. With an angle of 6350° set back becomes necessary when the total height of the building exceeds twice the width of road or street.

47. Floor space index (FSI). It is the ratio of the total built-up area inclusive of walls of all the floors to the area of the land on which the building stands. The value of FST e fixed by the local authority and it is different for different areas and for different buildings of the town.

FSI criteria control the development activity on the plot and thus can be used as a measure to check the density of the population. The unused F.S.I. indicates the potential or hidden value of the land.

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