# Plinth Area | What Is Plinth Area | Plinth Area Meaning | How to Calculate Plinth Area of a Flat | Plinth Area Estimate10 min read

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## What Is Plinth Area?

The total area of the building including interior and exterior wall, measured at floor level of the basement or at any story including balconies, is defined as Plinth Area.

The Plinth Area in simple words can be defined as the total area from external wall to external wall instead of internal wall to the internal wall.

If the measured area is from internal wall to internal wall then it is called a Carpet Area. Besides this, in other construction terms, the plinth area can also be referred to as the column pad area, hence it becomes important to clarify before assuming anything.

However, as discussed earlier the plinth area is also referred to as the total area occupied by the building along with the interior or exterior wall.  It is normally greater by 10 to 20 % of carpet area, which includes the exclusion of walls and other components.

Read More: What Is Plinth | What Is a Plinth Beam | What is Height of Plinth | What is Plinth Protection | Purpose of Plinth Protection

## Plinth Area Meaning

The Plinth Area is a Covered Built-Up Area occupied by the building including internal and external walls, which is generally 10-20% more than the carpet area. Sometimes Plinth Area is also known as Built-Up Area.

The Plinth Area is calculated at the floor level of any story or at the floor level of the building basement. Formula wise it is calculated as the sum of the Carpet Area of the building, area of the balcony, and areas of the walls.

It is mandatory to calculate the plinth area length of a building to be 1-inch adjacent if the unit of measurement used is in feet. Calculation of Plinth Area provides the constructor vital information regarding the cost of the building. Hence it is important to know the Plinth Area of the building.

## Plinth Area Definition

The total area of the building including interior and exterior wall, measured at floor level of the basement or at any story including balconies, is defined as Plinth Area.

While calculating Plinth Area, balconies are included whereas components such as ducts/ services and lift shaft (except in the lowermost floor of lift shaft) and open cut-out areas are excluded.

Calculation of the plinth area is done by taking the external dimensions of the building at the floor level however, in the case of calculating the floor area the internal measure of the building is which does not include the thickness of the walls.

## The Functions of the Plinth Area

The Plinth Area has the following functions,

• Calculation of Plinth Area provides vital information about building to architects and civil engineers.
• Relying on Plinth Area an architect could design the blueprints of construction projects.
• In similar way, civil engineers utilize the plinth area in order to construct a building unit.
• Plinth Level is laid over the calculated Plinth Area which sustains the weight of columns built over it.
• Plinth level built over Plinth Area also blocks the moisture of the ground to move upward and distribute the load of columns and foundation evenly.
• Plinth Area could give the cost estimation of a building unit after surveying and also provides ample information on property taxes imposed by some governments.

## Plinth Area Rate

The Plinth Area Rate for rating area and construction of buildings is categorized into three parts. This is as listed as follows,

1. For Residential Building
2. For Non-Residential Building/ Commercial Buildings
3. For Hospital Building

### 1.  For Residential Buildings

In the case of a residential load-bearing structure or building, the foundation plinth area rate as per the rating agency for 1 sq.m. Is 3870, for super-structure is 8625, and for finishing is 1450.

However, for frame structure, the rate of the superstructure is 12025 per 1 sq.m. and the finishing 1530.

### 2.  For Non-Residential Building

For Non-Residential buildings in load-bearing structures, the foundation plinth area rate per 1 sq m is 2980, super-structure is 7310 and for finishing is 1495.

While for the frame structure in Non Residential type, the foundation plinth area rate for 1 sq m area is 4590, with its super-structure and finishing as 9035, and 1530 respectively.

### 3. Hospital Building

Hospital Building has the lowest rate as compared to Non-Residential and Residential per plinth area. In which in case of a load-bearing structure, the foundation plinth area rate per 1 sq.m. is 2970, super-structure is 8190, and finishing is 1495.

Similarly, for the frame structure, the foundation plinth area rate per 1 sq.m. is 4590, for super-structure is 12535, and for finishing is 1530.

Read More: What is Plot Area | Built-up Area | Carpet Area | Types of Area In Building

## Plinth Area Estimate

Plinth Area Estimate is considered as an approximate estimate in which the plinth area of a building is multiplied with plinth area rate to obtain an estimate for the building i.e. Plinth area rate per sq m x plinth area of the building (in m).

Plinth Area Estimate provides us the proper construction cost rather than calculating the details. The plinth area is calculated as per the roof area of a building using the external dimension. While computing plinth area courtyard area etc. should be excluded from it.

Plinth Area Rates are subtracted from the cost of the equivalent building in the same locality containing approximately or exactly the same finishing that too at the same conveniences.

With the purpose of controlling the difference in the construction cost of the building the desired height of the building should be built within the same year of construction or in advance.

The plinth area estimation is supported by the Report, Line Plan of building, Detailed Specifications, and Line Plan of the building for which the plinth area rate is determined.

## How to Calculate Plinth Area of a Flat?

While we Calculate the Plinth Area of a Flat, we must consider the following areas,

• We must consider the area of the wall without plinth offsets at the floor level. And if any common walls exist among two buildings then only half of the area of such walls should be considered in the plinth area.
• In case of building with columns that are proposed outside the cladding then plinth area estimation is done outside cladding.
• Components such as the lift well along with landing and the vertical duct for air conditionings are also estimated.
• 50% of the area should be taken into consideration if the area is uncovered with projections.
• Around 25% of the total area should be considered while calculating, when the recess height is up to 1.0 meters, however it is to be considered 50% when the recess height is 1.0 to 2.0 meters.
• To estimate plinth Area of the internal shaft for sanitary installations, garbage chute, telecom, electrical, and firefighting services under the condition that these do not go beyond 2m2 in the area.
• The area of staircase room or head room excluding terrace level should be considered.
• Similarly components such as Machine room and Porch are included as well.

## In the Calculation of Plinth Area, Some Things Should Be Considered That Are?

• While estimating the foundation cost the plinth area of the ground level of the building should be taken into consideration.
• Even for estimating super-structure cost the plinth area should be taken for the calculation.
• Similarly, for the calculation of the roof slab finishing the plinth area at the Ground level of the building is considered for estimation.
• For Super Structure cost of school building a standard value of 80% of the Super Structure cost of Non-Residential Buildings is assigned.
• For construction of super-structure in earthquake-prone areas, the rates are adopted as per Annexure-V in construction industry.
• For construction in sea water front the construction cost per meter square of area is – Rs.243 up to 10 km distance.
• Important increment of about 25% over the superstructure cost of the respective type of building is to be added to the basement or ground floor.
• Taking Lift charge into consideration an extra Rs.34/ m2 should be added in the plinth area calculation for the upper floors.

Read More: 18 Components of Building | Building Structure | Parts of a Building

## While Measuring the Plinth Area, Things Should Not Be included Are?

As we had discussed things that should be considered in the calculation of the Plinth Area, It is also important to know the things that should not be contained.

This helps in reducing the construction cost of the building, saving the extra materials to be buoyed. Things that should not be included areas listed below,

• Area of extra floor for faciliting accommodation in assembly halls, auditoriums and theatres.
• Open platform
• The Cantilevered porch hanging outside
• Balcony of Building
• The Lofted Area
• Terrace made at first floor in multi storey building
• Internal sanitary shaft and garbage chute are excluded if they are in excess of 2 m2 with respect to area.
• If Spiral staircase is present in the building then its area along with landing is excluded.
• Rising Structures such as Towers, Turrets and dome projecting over the terrace should not be calculated.
• Area of architectural features like slab projection for arranging flower pots and vertical sun breaker or box louver projecting out are neglected.

## FAQs

### Plinth Area Meaning

The Plinth Area is a Covered Built-Up Area occupied by the building including internal and external walls, which is generally 10-20% more than the carpet area. Sometimes Plinth Area is also known as Built-Up Area.

### Plinth Area Definition

The total area of the building including interior and exterior wall, measured at floor level of the basement or at any story including balconies, is defined as Plinth Area.

### How to Calculate the Plinth Area of a Flat?

The plinth area of the Flat can be calculated as the sum of the Carpet Area of the building, area of the balcony, and areas of the walls. It is mostly 10-20% more than the carpet area.

### What Is Plinth Area?

The Plinth Area is a Covered Built-Up Area occupied by the building including internal and external walls, which is generally 10-20% more than the carpet area. Sometimes Plinth Area is also known as Built-Up Area.

### What is the difference between the plinth area and floor area?

Talking about the Plinth Area, it is calculated by taking the external dimensions of the building at the floor level. However, when it comes to calculating the Floor Area the internal measure is necessary in order to lay the carpet which does not include the thickness of the walls and an internal measure.

### Is Verandah included in the plinth area?

Yes, Verandah is included in Plinth Area along with balconies and parapets. However, their area consideration varies accordingly, such as if this area is secured by projections, in plinth area full area is included and if un-secured by projections then only 50% of the area is included.

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