Calculation of Building Area for Prefabricated Houses

The calculation of the building area for prefabricated houses is primarily based on the rules for calculating building areas, with specific rules as follows:

I. Single-story Buildings For single-story prefabricated houses, the building area is calculated as the sum of the horizontal projected areas above the exterior wall plinth for each floor. If prefabricated panels are used for single-story rural self-built houses, the area is calculated according to this rule. Areas with a height of 2.20 meters or more are counted as full area; areas with a height of less than 2.20 meters are counted as half area. For example, if the height above the exterior wall plinth of a single-story prefabricated house is 2.5 meters, its entire horizontal projected area is included in the building area; if the height is 2.0 meters, only half of the area is counted.

II. Multi-story Buildings The calculation of the building area for multi-story prefabricated houses requires layer-by-layer processing:

1. Ground Floor: Calculated based on the horizontal area of the structural perimeter above the exterior wall plinth.
2. Floors Above the Ground Floor: Calculated based on the horizontal area of the exterior wall structural perimeter. Floors with a height of 2.20 meters or more are counted as full area; areas with a height of less than 2.20 meters are counted as half area. For example, for a two-story prefabricated house with a ground floor height of 3.0 meters and a second floor height of 2.1 meters, both floors are counted as full area; if the second floor height is 2.0 meters, only half of the second floor area is counted.

III. Calculation of Areas in Special Zones

1. Balconies: If prefabricated panels are used for balconies, the area is calculated as half of the horizontal projected area, regardless of whether the balcony is enclosed or not.
2. Space Under Sloped Roofs: If prefabricated panels are used for space under sloped roofs, the calculation method is divided according to the clear height:
   • Clear height exceeding 2.10 meters: Counted as full area.
   • Clear height between 1.20 meters and 2.10 meters: Counted as half area.
   • Clear height less than 1.20 meters: Not counted as area. For example, in a prefabricated house with a sloped roof, if some areas have a clear height of 2.3 meters, some have 1.8 meters, and some have 1.0 meters, they are calculated as full area, half area, and zero area, respectively.

IV. Precautions

1. Measurement Accuracy: When calculating the area of prefabricated panels, appropriate tools such as laser distance meters should be used to take multiple measurements at key positions such as the exterior wall plinth and structural perimeter, and the average value should be taken to improve the accuracy of the results.
2. Regulatory Compliance: It is necessary to understand and comply with local regulations regarding the building area of rural self-built houses. For example, some regions may have special requirements for the upper limit of the building area per household and height restrictions to ensure that the use of prefabricated panels and area calculations comply with regulations.