1.1 INTRODUCTION
Building planning means imagining the details of a building to be built and putting them in the form of drawings so that the builders, owners and others understand the features of the building. The objective of this chapter is to explain
- Criteria for site selection
- Important municipal laws regarding building plans
- Basic principles of building planning.
- Basic requirements of residential buildings
1.2 SITE SELECTION
Many times there may not be any choice for selecting a building site but to plan the building in the site available to the owner. However if there is chance to select the site the following points may be noted:
- The site should be located in a developed area. Owners naturally prefer the locality where the people of their status live.
- The site should be located where the following facilities are available
- a. Means of public transport
- b. Utility services like water supply, electricity, drainage etc.
- c. Amenities such as school, market, bank, hospital etc.
- d. Community services like street cleaning, waste cleaning, police and fire protections.
- The site should meet the extent of privacy desired.
- It should be on an elevated place.
- It should be in a locality where natural and man-made environments provide healthy living and working conditions.
- The site should be away from quarries, kilns, factories, badly maintained drains and water logged areas.
- The soil at site should have high safe bearing capacity so that the cost of foundation is reduced.
1.3 ABOUT BUILDING BY-LAWS
To prevent haphazard development and to achieve the following objectives, National Building Code of India 2005 prescribes the building by laws:
- To allow orderly growth
- To afford safety against fire, noise, health hazard and structural failures
- To ensure minimum standards
Municipalities and other competent authorities have powers to make changes in these by laws to suit their local requirements like:
- Aesthetic considerations in the vicinity of monumental buildings.
- Development which may be the general characteristics of hospital, architectural or other monumental
- Consideration of safety near airports.
1.4 TERMINOLOGY
Before going through building by-laws it is necessary to clearly understand the following terms (as per National Building Code 20051&2):
a. Building height: The vertical distance between the centre line of the street and the highest point of the building is considered as building height. In case of flat roofs, the height is upto top of the parapet [Fig 2.1(a)]. In case of pitched roof, the building height is considered upto the point where the external wall touches the sloping roof [Fig 2.1(b)]. In case of the gable facing the street, the height is considered upto the mid-height of gable end [Fig 2.1(c)]. The features provided only for architectural purposes should not be considered for finding the height.
b. Building line: It is the least horizontal distance of the permanent portion of the building from the centre of the street in front of the building. The competent authorities fix minimum building line to take care of future widening of the road, safe distance from electric line etc.
c. Set backs: Set backs are line parallel to the boundaries of the sites. They are fixed on the front, rear boundaries and side boundaries of the site. No permanent part of the building is to be constructed beyond these lines.
d. Covered or built-up area: The area covered by the building immediately above the plinth level is called covered area or built-up area. However it does not include the following:
- Storage tank
- Well structure
- Ramp / steps
- Open verandah, portico
- Uncovered staircase
e. Floor area ration (FAR): It is defined as the ratio of total covered area of all the floors to the area of the plot. Thus
f. Floor area: Floor area is equal to the plinth area minus area occupied by walls and columns.
1.5 IMPORTANT BY-LAWS ABOUT BUILDING
The important by-laws framed by National Building Code are presented below. Depending upon local conditions competent authorities can make certain changes, Hence before planning a building, the local by-laws should be looked into.
a. Distance from power supply main: To safeguard from mishaps of electrocution, the distance between any accessible part of the building (balcony, terrace) and electricity supply main should have minimum vertical and horizontal distances as shown in Table2.1.
Table 2.1. Minimum distance from Power line
b. Exterior open-spaces: It governs the requirement of minimum open spaces around the building:
(i) Front Open Spaces: It depends upon street width in front of the building [Ref Table 2.2]
Table 2.2 Minimum front open space
Note:
- 1. For sites abutting two or more streets the value of open space is based on the average width of street, but is no case it is less than 1.8 m for the cases 2, 3 and 4 above.
- 2. For the streets less than 7.5 m in width the distance of the building line shall be at least 5 m from the centre line of the street.
(ii) Rear Open Space: Minimum rear open space should be an average of 3.0 m and in no case it is less than 1.8 m. In case of back to back sites rear open space should be 3.0 m throughout. For plots of depth less than 9.0 m and buildings of height less than 7.0 m minimum is reduced to 1.5 m.
(iii) Side Open space: Minimum side open space recommended is 3.0 m on each side for detached buildings while for semi detached houses it is 3.0 m on one side. However for smaller plots competent authority may reduce it to 1.5 m. For buildings of height more than 10m. The minimum open spaces, side as well as rear, shall be shown in Table 2.3.
Table 2.3. Minimum Rear and side Open Space
Note:
- 1. For buildings above 24 m height, minimum front space is 6 m.
- 2. If length or width of building exceeds 40 m, add 10 percent of width minus 4 m to the minimum requirement.
C. Floor Area Ratio (FAR): Based on fire protection consideration maximum FAR prescribed for different occupancies facing a public street of at least 9m width are as shown in table 2.4.
Table 2.4. Maximum FAR
Note:
- 1.UL – unlimited
D. Height of building: If building height is not covered by FAR required and open space requirement, the maximum height is limited according to the width of the street as follows:
- If the site is having only front street, height is limited to 1.5 times the width of front road plus the front open space.
- If the site is having two or more streets, height is to be determined on the basis of wider street, but permitted upto a depth of 24 m along the narrow street.
- In the vicinity of aerodrome, the maximum height is fixed in consultation with civil aviation authorities.
1.6 BY-LAWS ABOUT REQUIREMENTS OF BUILDINGS COMPONENTS
The following are the important bylaws about building components:
a. Plinth Height:
To avoid difficulties in drainage, plinth height should be 450 mm above the surrounding ground level. Every interior courtyard should be at least 150 mm above the nearest street.
b. Habitable rooms:
Such rooms should satisfy the minimum requirements shown in Table 2.5
Table 2.5 Minimum Requirements of Habitable rooms
c. Kitchen:
It should have impermeable floor flue, if necessary and a window or ventilator or an opening of suitable size. It should satisfy the minimum size requirements shown in Table 2.6
Table 2.6 Minimum size Requirements of Kitchen
d. Bath Rooms and water closets:
At least one wall should abut the exterior open space. High level window or ventilator should be provided. It should have impervious floors sloping towards drain. Wall should be finished with impervious material to at least 1m above the floor. The size requirements are as shown in Table 2.7
Table 2.7 Minimum size requirements
e. Store Room:
It should not be less than 3.0m2 in area and 2.2m in height
f. Staircase:
In a residential building staircase should satisfy the following requirements:
Minimum rise = 190 mm
Minimum tread = 1250 mm
Minimum width = 750 mm
Minimum head room = 2.2 m
g. Parapet
Parapet walls and hand rails provided on the edges of roof terraces, balcony, verandah etc. should not be less than 1.05m and not more than 1.2m in height from the finished floor level.
h. Compound wall:
The maximum height of compound wall shall be 1.5m above the centre line of the front street. However compound wall upto 2.4m height is permitted if the top 0.9m is of open type, approved by the authorities. In case of corner plots, the lower 0.75 m may be of solid masonry but the top portion should be open type at least for a distance of 10 m from the intersection point.
a. Aspect: Aspects means arrangement of doors and windows in the external wall to make good use of sun, breeze, scenic view etc. Kitchen should have eastern aspect means kitchen should be located on eastern side of the building. The idea of having eastern aspect is to make use of morning sun. The following aspects are desirable (in the northern hemisphere):Kitchen: Eastern aspect
- Dining Room: Southern aspect to enjoy winter, sun.
- Drawing and living room: Southern or South eastern aspect to enjoy winter sun.
- Bed rooms: Western or south western aspect to enjoy breeze in summer
- Reading rooms, class rooms, stairs: Northern aspect to enjoy defused light.
b. Prospects: Prospects is about locating and selecting type of doors and windows in outer walls so as to provide aesthetically good view. Quality of doors and windows, projections and grills to windows need planning for the prospects.
c. Roominess: It refers to suitable proportioning of length, width and height of rooms. Length to width ratio should be 1.2 to 1.5. If it is nearly square lot of area is wasted for movement and if it is more than 1.5 it gives the tunnel effect. Doors should be properly located so that utility and privacy is maximum. Proper colour to walls and floor give roominess effect. Light colour creates effects of more space. Cupboards or lofts provide increased utility.
d. Furniture requirements: Furniture requirement plays an important roll in planning. In designing a drawing room position of sofa, chairs, TV etc. should be drawn and checked for circulation area. For bed rooms, the position of cots, dressing tables, cupboards should be drawn and circulation area checked. In planning office, laboratory, hospital buildings position of required furniture should be drawn and checked for circulation area. In planning hostel rooms the positions of cots, study tables and wardrobes should be drawn and checked.
e. Grouping of rooms: Grouping of rooms means disposition of rooms in the building for the convenience of uses. Dining room should be close to kitchen, while sanitary block should be away from kitchen but at convenient place to bed rooms. In case of offices, the administrative department is located centrally. In factories various sections are so located that the products move in one direction and finished product comes out near office and show rooms.
f. Circulation: Passages, lobbies, halls serve horizontal circulation while stairs and lifts serve vertical circulation. Within a room also a portion of it serves for circulation. The following points should be considered while planning circulation:
- Dining Room: Southern aspect to enjoy winter, sun.
- Drawing and living room: Southern or South eastern aspect to enjoy winter sun.
- Bed rooms: Western or south western aspect to enjoy breeze in summer
- Reading rooms, class rooms, stairs: Northern aspect to enjoy defused light.
g. Elegance: Elegance means the general effect felt by viewers from outside. It depends upon positions of doors, windows, ventilators, balconies, sun shades, staircases etc. Elevations should be attractive. The width, length, height and projections contribute a lot for the elegance. It may be noted that Taj Mahal is famous for its elegance.
h. Sanitation: It includes providing good lighting, ventilation and sanitary conveniences.
- Light: Natural light provides hygienic atmosphere. Light should be uniformly distributed. Providing windows and ventilators of appropriate size at suitable positions contribute a lot for natural lighting. In residential buildings window area to floor area should not be less than 1/10 while for school buildings it should be about 1/5.
- Ventilation: Natural ventilation is preferred. This is achieved by selecting and positioning of doors, windows and ventilators. In case it is not possible to achieve natural ventilation for any part of the building, ordinary or exhaust fans should be provided.
- Sanitary convenience: Provision for bath rooms, lavatories, urinals etc are not only necessary but statuary requirement also. They should be sufficient and provided at convenient locations. They should have proper slopes and impervious floors and walls.
- Flexibility:
This means a room designed for specific purpose should be possible to use for other purpose, if there is a necessity. If a partition is provided between living room and dining room, it is possible to remove partition wall and use for family functions. A study room may be planned for using as a guest room. If independent access is provided to backyard near kitchen, backyard can be used for dinner functions. Thus in planning flexibility also should be considered.
i. Privacy: Planning should take care of privacy of one room from other room as well as parts of the buildings from street and neighbouring buildings. This is achieved by proper grouping of rooms and by providing doors, windows and ventilators at suitable positions. Planning entrance to building also contributes a lot to privacy.
j. Practical considerations: Cost of construction is a major practical consideration in planning. Based on the amount owner can invest, the plinth area that can be built may be found by getting prevalent rates. The scope for future improvements or extensions should be provided. Some of the future renovations to be planned are:
- Improving elevations without dismantling any part of the building
- Improving flooring
- Extending building horizontally or vertically without dismantling existing building.
1.8 BASIC REQUIREMENTS OF A BUILDING
The planning and construction of any building should satisfy the following basic requirements:
- Strength and stability
- Dimensional stability
- Resistance to dampness
- Resistance to fire
- Heat insulation
- Sound insulation
- Protection against terminate
- Durability
- Security against burglary
- Lighting and ventilation
- Comfort and conveniences
- Economy
i. Strength and stability: Most important requirement of a building is it should be capable of transferring expected load in its life time safely to the ground. None of its structural components should buckle, overturn or collapse.
ii. Dimensional stability: Excessive deformations of structural components like beams and slabs give a sense of instability. They result into cracks in structural elements and walls. It is necessary that structural design satisfies the serviceability requirement also.
iii. Resistance to Dampness: Dampness in a building results into hygienic problem. It reduces the life of the building also. Great care should be taken in planning and construction to avoid dampness.
iv. Resistance to fire: To achieve resistance to fire the requirements are:
a. The structure should be built with materials that do not ignite easily
b. Building orientation should be such that spread if fire is slow.
c. In case of fire, there should be means of easy routes to vacate people quickly.
v. Heat Insulation: A building should provide comfortable stay for the inmates from heat in summer and from cold in winter. The thickness of walls and roof contribute a lot towards heat insulation. Use of hollow bricks give thermal comfort.
vi. Sound Insulation: Building should be planned against outdoor and indoor noises.
vii. Protection from Termite: Building should be protected from termites.
viii. Durability: Each and every component of building should be durable for the life time the building is designed This is achieved if the building is made damp proof and leak proof. The structural design should be satisfactory.
ix. Security against Burglary: This is the basic requirement of a building. This is achieved by providing stronger walls and outer doors.
x. Lighting and ventilation: For healthy and happy living natural light and ventilators are required. Diffused light and good cross ventilation inside the building are required.
xi. Comfort and conveniences: Various units in the building should be properly grouped and integrated keeping in mind the comfort and convenience of the user.
xii. Economy: Economy without sacrificing comforts convenience and durability is another basic requirement of building. It is achieved by properly grouping rooms, minimizing circulation area within the building and by minimizing number of doors and windows suitably.
Use of innovative materials and local materials, innovative construction technology like monolithic construction, precast constructions also helps in bringing down construction cost. Evaluating actual bearing capacity of the soil, carrying out detailed structural analysis and design are also required in achieving economy. Locating beams and columns suitably to minimize / avoid eccentric loads should be planned. In case of beam and slab floor construction cost can be minimized if beams are spaced at a distance of 5/8th their span.
1.9 BUILDING DRAWINGS:
After planning a building the following drawings should be prepared.
- Key plan
- Site plan
- Building plan
Key Plan: It should show the boundary locations of the site with respect to neighborhood land marks. It should be to scale not less than 1 in 10000.
Site plan: Site plan should be drawn to a scale not less than 1 in 500 for a scale upto 1 hectare and not less than 1 in 1000 for a site more than one hectare. It should show
- The boundaries of the site
- The position of the site in relation to neighboring street.
- Name of the street
- If there is no street within a distance of 12m, the nearest existing site
- The means of access from the street
- Frontage and setbacks
- North direction
- Physical features such as wells, drains etc
Building Plan: The plan, elevation and sections of the should be drawn to a scale 1:100
The drawing should show:
- All floor plans clearly indicating covered area
- Size and spacing of all framing members, internal sizes of rooms, width of passages, positions of stair cases, ramp, lift etc.
- Use or occupancy of all parts
- Locations of water closets, sinks, baths etc.
- Sectional drawings should clearly show footing details, thickness of slabs, beams, lintels, height of rooms, parapet etc. At least one section should be through the staircase.
- Elevation of all floors from street
- Dimensions of projected portions
- North direction
The plans should be signed by appropriate authority.
Published by:
Task Force for Quality Assurance in Public Constructions
GOVERNMENT OF KARNATAKA ISBN
Important Note:
This reference manual is intended for the use of Government Engineers.
Disclaimer:
Every effort has been made to avoid errors or omissions in this publication. In spite of this, some errors might have crept in. Any mistake, error or discrepancy noted may be brought to our notice which shall be taken care of in the next edition. It is notified that neither the publisher nor the authors will be responsible for any damage or loss of action to any one, or any kind, in any manner, therefrom.