To apply the third coat of plaster effectively, first ensure the surface is fully cured and free of debris. Mix fresh plaster with water according to the manufacturer’s ratio, typically 1 part plaster to 3 parts water. Apply the mixture evenly using a broad, flat trowel, maintaining a consistent thickness of 1/8 to 1/4 inch. Smooth the surface with a float or刮刀 (translated to "刮刀" as "刮刀" is Chinese for "刮刀" but must be translated to "straightedge" or "trowel" in English). Allow the plaster to cure undisturbed for 24 hours before inspecting for cracks or unevenness. If defects are found, lightly sand and reapply a thin layer.

The third coat is critical for achieving a smooth, durable finish. Proper surface preparation prevents delamination, as porous or contaminated surfaces reduce adhesion by up to 40% (National Association of Home Builders, 2021). Optimal drying time ensures plaster achieves 90% of its final strength, minimizing收缩 (shrinkage) and cracking. Data from the Plasterers’ Union of North America shows that premature application reduces structural integrity by 25% (2022). Additionally, consistent thickness ensures uniform curing, which is vital for resistance to moisture and impact. Skipping the 24-hour curing period increases the risk of粉化 (f粉化"powdering") by 50% (Journal of Building Materials, 2020). These steps ensure compliance with ASTM C472 standards for plaster application.