Budget for the whole duplex
A family duplex typically connects two levels internally. Two independent homes on separate floors are a different brief: they may need separate entrances, kitchens and service arrangements. Establish which arrangement you want before comparing costs.
Plot area and built-up area are different
A 1,500 sq.ft total G+1 house might have 750 sq.ft on each floor. That is 1,500 sq.ft to price once, not 1,500 multiplied by two again. The permitted footprint must be checked for the specific plot and proposed building.
An illustrative package calculation
Using Izhlan Infrastructure’s published residential specifications:
| Total built-up area | Standard at INR 2,199/sq.ft | Premium at INR 2,599/sq.ft |
|---|---|---|
| 1,000 sq.ft | INR 21,99,000 | INR 25,99,000 |
| 1,500 sq.ft | INR 32,98,500 | INR 38,98,500 |
| 2,000 sq.ft | INR 43,98,000 | INR 51,98,000 |
These are area-times-rate examples, not site quotations. Confirm taxes, fees, special foundations, external works and interiors in your actual proposal. See the package comparison for the listed materials.
Design decisions to make early
- Staircase: Locate it around circulation, daylight and how independently the floors should function.
- Bathrooms and kitchens: Coordinate plumbing routes and maintenance access across levels.
- Parking: Check applicable requirements before allocating the ground floor.
- Future use: Tell the designer about possible separate occupation, accessibility needs or future expansion.
- Shade and ventilation: Review the orientation of rooms and openings for your site.
Ask for a site-specific structural design
An additional floor affects loading, the foundation and the structural scheme. Future extensions must be considered by the engineer now; they are not safe to assume from a render or a generic package description.
Make the budget complete
Ask for the measurement method and a written list of inclusions and exclusions. Clarify whether balcony, stair, terrace and covered parking areas are measured differently. Align payment stages with the agreed scope and programme.
Use the calculator for a starting figure, read costs beyond the package, or discuss your duplex.