Understanding FAR in Building Rules and Regulations

 Lecture - 08

Floor Area Ratio (FAR)

Floor Area Ratio (FAR) is a key urban planning metric that determines the maximum allowable floor area of a building in relation to the size of the land on which it is built.

Key Points About FAR:

1.     Regulates Building Size: FAR determines how much floor area can be built relative to the size of the land.

2.     Controls Density: A higher FAR allows for taller or larger buildings, increasing population density.

3.     Zoning Tool: Local governments use FAR to manage urban growth, infrastructure, and environmental impact.

4.     Varies by Location: FAR limits differ based on the city, zone, and type of development (residential, commercial, etc.).

 

Why is FAR Important?

• Ensures orderly development in urban areas.
• Prevents overcrowding and overuse of infrastructure.
• Balances open space and built-up areas.
• Influences property values and urban aesthetics.

 

 

 

The floor area must not exceed the Maximum Ground Coverage (MGC). Each Floor Area Ratio (FAR) value corresponds to a specific MGC, which can be determined from the FAR table.

Floor Area = Land Area x MGC

 

Typical Example:

What is the maximum build area and floor count for a 4500 sqft. land in Dhaka with FAR 3.75 and MGC 60%?

Given:

• FAR (Floor Area Ratio): 3.75
• Land Area: 4500 sqft
• MGC (Maximum Ground Coverage): 60%

 

Step 1: Calculate Floor Area

The Maximum Ground Coverage (MGC) is the percentage of the land area that can be covered by the building's footprint.

Floor Area=Land Area×(MGC/100)

                  = 4500 sqft × 0.60 =2700 sqft

So, the building's footprint (ground floor area) cannot exceed 2700 sqft.

Step 2: Calculate Maximum Allowable Building Area

The FAR determines the total allowable building area across all floors.

Maximum Building Area=Land Area × FAR              

                                          = 4500 sqft × 3.75 = 16,875 sqft

So, the total building area / gross floor area across all floors cannot exceed 16,875 sqft.

Step 3: Determine the Number of Floors

To find the number of floors, divide the Maximum Building Area by the Floor Area:

Number of Floors = Maximum Building Area / Floor Area ​           

                               = 16,875 sqft / 2700 sqft

                                = 6.25Number of Floors

Since you cannot have a fraction of a floor, the maximum number of floors allowed is 6 floors.

Finally:

·         Floor Area: 2700 sqft

·         Maximum Building Area (FAR): 16,875 sqft

·         Number of Floors Allowed: 6 floors