Standard Building Dimensions: What You Need To Know

Building Bye-Laws are the restriction laid down by municipal, urban development authorities, and other government departments a town planning trusts related to clear space to be left around the building, permissible construction area, etc.

Hence the proposed plan of the building is to be prepared according to the bye-law which are checked and approved by the above authorities.

This decides the Building Dimensions Standard in residential buildings.

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Building Dimensions Standard

The standard dimensions of the building and the building size are as follows.

Building Dimension Standard — House Plan

1. In order to be free from weathering effects and for better stability, the minimum depth of the foundation is kept 1m below the ground level.

The width of the foundation should be such that the stress on the soil is within its safe bearing capacity.

2. Minimum dimension for plinth: Plinth height may be 300 mm to 600 mm but 450 mm is more common.

For water-logging-prone and important buildings, the minimum plinth height is 600 mm. With greater plinth height, the building gets a majestic appearance.

3. Plinth Area should be a minimum of 1.2 times the floor area of the building. The minimum width of the footing is 100 m more than the one above and the minimum depth of footing is the depth of the standard brick 100 mm.

4. When a number of footings are to be provided preferably their depths are kept equal.

The width of the cement concrete bed of the foundation = width of the brick footing immediately above the concrete bed + 100 mm + 100 mm. (i.e. 100 mm is the minimum offset for the concrete bed).

5. Minimum width of footing = 2t + 2j

Where, t = Thickness of wall immediately above basement level (Not less than 200 mm )

j = offset of concrete (Not less than 100 mm)

6. Thickness of the damp proof courses 20 mm to 25 mm.

7. Thickness of the cement concrete floor is a minimum of 100 mm plus floor finish over it. Floor finishes are generally 10 mm to 20 mm thick cement mortar or tiles.

8. Ceiling height (i.e., headroom) for main rooms of the residential building should be 3000 mm to 3600 mm.

For bath and W.C. the ceiling height may be 2000 mm to 2750 mm. (maximum height of the building depends upon the types of structure)

9. The carpet area should be 50 to 65% of the floor area.

10. Main entrance door of a residential building should be 1000 mm x 2100 mm in size. Other doors should have a minimum width of 900 mm and a height of 2000 mm.

Doors for the garage are 2500 mm x 2300 mm and for W.C. and bathrooms are 600 mm to 750 mm x 1800 mm with the single-leaf shutter.

11. The size of windows depends on the total area of window openings required.

The following guidelines should be kept in mind,

(i) Window width = 1/8 (width of room + height of room).

(ii) Glass area in windows should be 10% to 20% of the floor area of the room for good lighting.

(ii) At least one sq.m. of window area should be provided for every 30 cubic meters of inside room space.

Generally, the minimum size of the window is 750 mm x 1000 mm

12. The minimum size of the ventilator is 1000 mm x 500 mm in order to provide good ventilation for any habitable room.

For bath and W.C. it should be a minimum of 450 mm x 300 mm. Its depth is greater than 450 mm or otherwise privacy is lost.

13. Minimum Room Dimensions for Residential Building.

Sr. No.	Name of Room	Minimum Dimension	Maximum Dimension
1.	Drawing Room or Living Room	4200 mm x 4800 mm	5800 mm x 7200 mm
2.	Bed Room or Master Bed Room	3000 mm x 3600 mm	4200 mm x 4800 mm
3.	Dining Room	3600 mm x 4200 mm	4200 mm to 4800 mm
4.	Kitchen	2500 mm x 3900 mm	3000 mm x 3000 mm
5.	Bath / WC Combined	1800 mm x 1800 mm	1800 mm x 2500 mm
6.	Bath (Separated)	1200 mm x 1800 mm	–
7.	W. C. (Separated)	1200 mm x 1200 mm	–
8.	Guest Room	3000 mm x 3600 mm	3000 mm x 3000 mm

Building Dimensions Standard

14. Standard Stairs Size

Rise in residential building = 130 mm to 190 mm.
Rise in office building = 125 mm to 150 mm.
Going – 275 mm to 350 mm for public buildings.
Going 250 mm to 300 mm for residential buildings.
For selecting the rise and tread of a building, the following thumb rules are followed,
2T X R = 550 to 650
T x R = 39000 to 48000
The width of the steps is 900 mm for residential buildings and 1000 mm for public buildings.
Number of Riser = (Total Height of floor / Height of riser)
Number of treads = Number of riser – 1

15. Thickness of R.C.C. I lintel beam of 100 mm to 250 mm and 150 mm is more common.

16. Thickness of R.C.C. roof slab is 100 mm to 150 mm (100 mm is more common) and that of sunshades is 25 mm to 50 mm.

17. Sunshade projection length in cm: sunshade projection through 450 mm or 500 mm beyond the facing of an external wall.

18. Width of the verandah is from 1.8 m to 3 m and the width of the passage is 0.8m to 1.2 m in residential houses.

19. The height of the parapet wall should not be less than 0.60 m and not more than 1.2 m above the finished floor level.

Building Bye-Laws

20. Height of various building components and Standard height of a building

Sr.No.	Description	Height(mm)
1	Plinth Level	450 to 600 from GL
2	Window Sill Level	900 from floor level
3	Lintel Level	2100 from floor level
4	Roof Slab Level	3000 to 3600 from floor level
5	Parapet Wall	600 to 900
6	Courtyard or Garage	1500 from GL
7	Foundation for Single Story	1000 below GL
8	Foundation for Double Story	1000 to 1200 below GL
9	Railing Height	850 from thread
10	Rise of Step	150 to 190

21. Standard Size of Sunshade:

The primary purpose of providing Sunshade is for controlling the amount of direct sunlight through your building’s window.

Conclusion

In conclusion, understanding and adhering to standard building dimensions is essential for ensuring that a building is structurally sound, safe for its occupants, and meets all relevant regulations and codes.

By taking into account factors such as ceiling height, door and window dimensions, and room sizes, architects and builders can create functional and aesthetically pleasing spaces that are optimized for their intended use.

Incorporating standard dimensions into building design and construction can also help to streamline the building process and reduce costs, making it a smart choice for both builders and clients.

FAQs:

What do you mean by building bylaws?

Building Bye-Laws are the restriction laid down by municipal, urban development authorities, and other government departments taking into account the requirement of building and simultaneously ensuring safety.

Why are bye-laws important?

Bye-laws are the restrictions which are for ensuring the proper building of a structure taking into consideration the safety and avoiding any further damage that might cause to the building.