A 30 × 40 ft plot is 1,200 sq.ft, the most common size we are asked to plan in Patna. It holds a comfortable 2BHK or a tight 3BHK per floor. The difference comes down to where the staircase goes and whether the car parks inside.
Start with what you lose to setbacks
Before a single room is drawn, the front setback, side margins and road-widening line (if any) are taken out. On a typical 30 ft frontage with a front setback and a small rear open space, you are usually left with roughly 850–950 sq.ft of buildable footprint per floor. That is the number to plan with, not 1,200.
Room sizes that work
- Hall / living: 12 × 15 ft is comfortable; 11 × 13 ft is the practical minimum for a sofa set and a TV wall.
- Master bedroom: 12 × 12 ft with an attached toilet of about 5 × 7 ft.
- Second bedroom: 10 × 11 ft takes a double bed and a wardrobe.
- Kitchen: 8 × 10 ft for an L-shaped platform; add a 4 × 6 ft utility if you can.
- Common toilet: 4.5 × 7 ft.
The staircase decides everything
A dog-legged staircase with a 3.5 ft flight width needs roughly 8 × 12 ft, about 95 sq.ft on every floor. On a 30 ft wide plot it usually sits along one side wall, near the entrance, so the upper floor can later be let out with its own access. Put it in the middle of the plan and you split the house into two awkward halves.
The compromise nobody expects
Most families want a car porch, a big hall and three bedrooms on the ground floor. On a 30 ft frontage you get two of those three. A car needs about 9 × 16 ft of clear space. Take it from the front and the hall moves back and loses light. Our usual answer is a 2BHK ground floor with parking, and the third bedroom plus family lounge upstairs.
Facing matters
An east or north road gives the easiest Vastu-friendly layout on this size. On south and west plots, the entrance position and a projection that shades the front need more thought. We cover this in our facing articles.
