For a 100 square meter house, approximately 10 to 12 bags of plaster are required, assuming standard coverage and waste factors.

The calculation hinges on plaster coverage rates and practical considerations. A typical 25-kilogram bag of plaster covers 10–12 square meters when applied at a standard thickness of 10–15 mm. For a 100-square-meter house, dividing the total area by the coverage per bag yields a baseline of 8.3–10 bags. However, construction experts recommend adding 10–15% extra plaster to account for uneven surfaces, jointing, and waste during application. Applying a 12.5% waste factor (common in residential projects) increases the total area to 112.5 square meters (100 × 1.125). Dividing this adjusted area by the coverage rate results in 9.3–11.25 bags. Rounding up to whole bags ensures sufficient material, leading to a practical range of 10–12 bags. Industry data from the National Association of Home Builders (NAHB) confirms that 10–12 bags are standard for 100-square-meter homes, aligning with typical plaster consumption rates of 0.1–0.12 bags per square meter. Surface preparation, such as cleaning and priming, further impacts usage efficiency, reinforcing the need for a buffer. Thus, 10–12 bags balances theoretical coverage with real-world application requirements.