What is the building area of a house? How is it calculated?

What is the building area of a house? How is it calculated?
The building area is also referred to as the expanded area of the building. It refers to the sum of the plane area of each layer determined by the outer wall of the residential building. It is an economic indicator of the scale of a building. It includes three items: area used, auxiliary area, and structure area. Because the building area is the settlement data for calculating the price of commercial housing, it is very important for buyers to know how to calculate the building area. In a residential building, the calculation scope and method of the building area are as follows:

(1) No matter the height of a single-storey building, the building area is calculated based on the peripheral horizontal area above the outer wall of the building. If a single-storey apartment has some floors (such as a loft), the building area should also be calculated.

(2) The area of multi-storey or high-rise residential buildings is calculated based on the sum of the area of each floor. The bottom layer is calculated based on the horizontal area above the outer wall of the building, two or more floors are calculated based on the horizontal area of the outer wall.

(3) the construction area of the basement, semi-basement, and corresponding entrances and exits is calculated based on the horizontal area of the outer wall of the upper exit (excluding the lighting well, tide-protected layer, and protection wall.

(4) use the deep foundation for the underground structural air layer. If the layer is over 2.2 meters, the building area is calculated based on half of the horizontal area of the outer area of the structural air layer.

(5) the building area is calculated on the first floor regardless of the height of the entrance and Hall in the building. The corridor area in the hall is calculated based on its horizontal projection area.

(6) elevator shafts, lifting wells, garbage collection channels, pipeline wells, and wall-mounted shafts all calculate the construction area based on the natural layer of the building.

(7) The technical layer (for various equipment and repair and maintenance) in a residential building. If the height exceeds 2.2, the area of the building is calculated based on the horizontal area outside the technical layer.

(8) The area of the independent canopy is calculated based on half of the horizontal projection area of the top cover. The area of the Multi-canopy is calculated based on the peripheral horizontal area.

(9) The building area shall be calculated based on the horizontal area of the perimeter of the housing, such as the stairway, water tank room, and elevator data center with an envelope structure.

(10) For an overhead corridor with a top cover between two buildings, the area of the building is calculated based on the projected area of the corridor. The overhead corridor without a top cover calculates the building area by half of its projected area.

(11) The area of the building is calculated based on the horizontal area of the perimeter of the enclosure.

(12) The area of the enclosed balcony and corridor shall be calculated based on the horizontal projection area on its periphery. The concave balcony calculates the building area by half of the balcony's clean area (including the balcony pane. The area of the building is calculated based on half of the horizontal projection area of the balcony.

(13) If a residential building has no stairs and an outdoor STAIR (including an evacuation ladder) is set up, the outdoor stair area is calculated based on the horizontal projection area on each layer. The building has stairs, if an outdoor STAIR (including an evacuation ladder) is set up, the outdoor stair area is calculated by half of the horizontal projection area on each layer. In addition, in residential buildings, the following areas are not calculated:

(1) component accessories, Art Decoration, and hanging (Wall) Boards that highlight the wall, such as columns, stacks, and legs.

(2) Outdoor ladders used for maintenance and fire fighting, with a steel ladder within 60 cm in width.

(3) chimney, flue, storage pool, and other structures independent of external walls.

(4) roof tanks without an enclosure structure.

(5) Technical layer (device layer) with a height of less than 2.2 ).

(6) single-storey residential rooms, such as operation rooms, control rooms, and instrument rooms.

(7) the ground floor of a deep foundation with a height less than 2.2 is provided, and the storage space of a slope building is suspended.

From the above, we can see that the building area of a residential building is complicated, not only with many regulations, but also with high professionalism and technology. When purchasing a house, if you do not know about this or are skeptical about the calculation result, you can consult a professional or a specialized measuring agency to remeasure the calculation according to the above criteria.