Calculating Building Floor Area

Currently, there is a significant increase in demand for house construction services, with the majority of customers opting for full-service house construction and selecting suitable contractors to build their homes.

Calculating Building Floor Area

Calculating Floor Area in Construction

According to the document QCVN 03:2012/BXD - National technical regulations on classification and grading of civil, industrial and urban technical infrastructure projects stipulate the following:
- Floor area of a floor: Is the floor area within the outer edge of the walls of the floor. The area of corridors, balconies, galleries... is also included in the floor area.
- Total floor area of the house: Is the total floor area of all floors, including basements, half basements, technical floors, attic floors, and roof floors.

1. Formula for Calculating Residential Building Floor Area

Building area (DTXD) = Usable floor area + Other areas (foundation, roof, yard, basement...)

Where:

- Floor area:

+ The area with a roof above counts as 100% of the area.
+ The area without a roof but with tiled floor counts as 50% of the area.
+ Empty spaces inside the house.
+ If less than 4 square meters, count as normal floor.
+ If above 4 square meters: count as 70% of the area.
+ If larger than 8 square meters: count as 50% of the area.

- Weakened ground reinforcement part:

+ The choice of reinforcement type depends on construction conditions, such as using wood or steel frames.
+ Using the method of pouring reinforced concrete, 20% of the area will be counted.

- Foundation part:

+ Single foundation counts as 30% of the area.
+ Excavating the foundation on concrete pile, drilled pile: 30% of the area.
+ Strip footing counts as 50% of the area.

- Basement section:

+ If the basement depth is less than 1.5m compared to the basement top code: count as 135% of the area.
+ If the basement depth is less than 1.8m compared to the basement top code: count as 150% of the area.
+ If the basement depth is less than 2.0m compared to the basement top code: count as 180% of the area.

- Yard section:

+ Under 20m² with pouring columns, pouring beams, building fences, laying floor tiles count as 100%.
+ Under 40m² with pouring columns, pouring beams, building fences, laying floor tiles count as 70%.

- Roof section:

+ Concrete roof with steel reinforcement, without floor tiles counts as 50% of the roof area, if there are floor tiles count as 10% of the roof area.
+ Tiled roof with iron rafters counts as 60% of the roof area.
+ Concrete roof glued with tiles counts as 85% of the roof area.
+ Metal roof counts as 30% of the roof area.

2. Illustrative example

- You have a building plot with an area of 100m², building a ground floor and 2 upper floors with a concrete roof. So, the floor area will be 3*100m² = 300m² (note: the upper concrete roof is naturally a floor, so only with a roof can you calculate the floor area of the 2nd floor).

- If you opt for a canopy, here's how you can calculate it. For instance, if your construction plot has an area of 100m2 with 1 ground floor, 2 upper floors, and a canopy-covered rooftop of 80m², the floor area calculation would be: 3*100m² + 80m² + 1/2*20m² = 390m².

- In the scenario where your calculated usable floor area is 500m² and the additional area including the foundation, roof, yard, etc., is 200m2, the total constructed area (TCA) would be: 500m² + 200m² = 700m².

This is an article on How to Calculate Floor Area in Construction. However, in contemporary construction practices, this calculation method is relatively indicative. For more specific details regarding costs and pricing, it's essential to clarify in the budgeting section, coupled with each specific task, to accurately calculate the total constructed area. For further insights on calculating floor area in construction, refer to this guide.