When it comes to constructing a building, one important aspect to consider is the plinth area. This term refers to the covered area of a building measured at the floor level of any of its stories or at the floor level of the basement. In simpler terms, it’s the space within the building that you can actually use.
The plinth area includes not just the floor space but also the external and internal walls. It encompasses everything the building occupies, and this area is typically 10% to 20% larger than what’s known as the carpet area, which is the actual floor space you can use. For example, if you have a 100 square meter plinth area, the carpet area might be around 80 to 90 square meters.
For measuring plinth area, we take very precise measurements, often to the nearest centimeter. If we’re using the foot system, we measure to the nearest inch. It’s important to measure different parts of the building separately. This includes floors (including any covered parts), basement, mezzanine floor, and even a garage if there is one.
Certain parts of the building are included in the plinth area, while others are not.
| Included in Plinth Area | Not Included in Plinth Area |
|---|---|
| Total floors, wall area at floor level (except plinth offset if any) | Cantilever porch, balcony, loft |
| Internal shaft area for installations (if less than 2 square meters) | Internal shaft area (if more than 2 sqm) |
| Air condition duct, lift well with landing | Domes, turrets, towers extending above terrace level |
| Habitable rooms, barsati, stair cover or mumty at terrace level | Architectural bends, cornices, etc. |
| Porch area (excluding cantilevered) | Vertical sun breakers, box louvres, projecting sunshades |
| Open platform, spiral staircase, landing, terrace at first floor |
We also need to account for the walls in our plinth area calculation. This includes the space taken up by walls on the plan of any floor. If any finishings or dados on the walls are higher than a meter, they are included in the wall thickness.
Once we have the plinth area, we can estimate the cost of building. This is a rough estimate obtained by multiplying the plinth area by the plinth area rate. This rate is determined based on the cost of similar buildings in the area.
For example, if the plinth area is 120 square meters and the rate is 2000 per square meter, the building cost would be:
Building Cost = Plinth Area × Plinth Area Rate
= 120 × 2000
= 240000
Additionally, we add costs for various aspects like water supply, sanitation, electrification, architectural work, and contingencies to get the total cost.
This estimate is approximate and gives us an early idea of the expected cost. It helps in planning and budgeting for the construction project.
