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Most asked 20 thumb rule based Interview Questions

  1. Minimum Room Dimensions for Residential Building.

Standard size of rooms in residential building pdf free download:

No .
Name of RoomMinimum DimensionMaximum Dimension
1.Drawing Room or Living Room4200 mm x 4800 mm5800 mm x 7200 mm
2.Bed Room or Master Bed Room3000 mm x 3600 mm4200 mm x 4800 mm
3.Dining Room3600 mm x 4200 mm4200 mm to 4800 mm
4.Kitchen2500 mm x 3900 mm3000 mm x 3000 mm
5.Bath / WC Combined1800 mm x 1800 mm1800 mm x 2500 mm
6.Bath (Separated)1200 mm x 1800 mm
7.W. C. (Separated)    1200 mm x 1200 mm
8.Guest Room3000 mm x 3600 mm3000 mm x 3000 mm

2. Stair Riser in residential building = 130 mm to 190 mm.

3. Stair Riser in office building = 125 mm to 150 mm.

4. Going – 275 mm to 350 mm for public buildings.

5. Going 250 mm to 300 mm for residential buildings.

6. 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

7. The width of steps is 900 mm for residential buildings and is 1000 mm for public buildings.

8. Number of Riser = (Total Height of floor / Height of riser)

9. Number of treads = Number of riser – 1

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

11. 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.

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

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

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


a]Plinth Level450 to 600 from GL
b]Window Sill Level900 from floor level
c]Lintel Level2100 from floor level
d]Roof Slab Level3000 to 3600 from floor level
e]Parapet Wall600 to 900
f]Courtyard or Garage1500 from GL
g]Foundation for Single Story1000 below GL
h]Foundation for Double Story1000 to 1200 below GL
i]Railing Height850 from thread
j]Rise of Step150 to 190

16.Main entrance door of a residential building should be of 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

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

18.Thickness of the cement concrete floor is a minimum of100 mm plus floor finish over it. Floor finishes are generally with 10 mm to 20 mm thick cement mortar or tiles.

19. 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 types of structure)

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