While "plaster coat" refers to a finish or layer applied using plaster material, the question likely intends to compare the materials themselves, specifically Plaster of Paris (POP), a common plaster material used for coats, with white cement. The primary difference between these two materials lies in their composition and strength.
According to the reference, white cement is made from limestone and clay, while Plaster of Paris is made of gypsum. This fundamental difference in source materials leads to varying properties.
Key Differences: Plaster Coat (POP) Material vs. White Cement
Let's break down the distinctions between Plaster of Paris, commonly used for plaster coats, and white cement.
Composition
- Plaster of Paris (POP): This material is derived from gypsum, a naturally occurring mineral. Gypsum is heated to remove water, resulting in a fine white powder.
- White Cement: As the reference states, white cement is produced from specific raw materials like limestone and clay, processed to minimize iron oxide and other impurities that give standard cement its grey color.
Strength
- Plaster of Paris (POP): While POP provides a smooth finish, it is generally less strong and durable compared to cement. It is relatively brittle and susceptible to water damage.
- White Cement: The reference highlights that cement is stronger when compared to Plaster of Paris. White cement, similar to grey cement in strength properties but differing in color, offers good compressive strength and durability.
Common Uses
- Plaster of Paris (POP): Often used for internal wall finishes, decorative elements like cornices and mouldings, false ceilings, and creating sculptures or casts. It's favored for its ease of application, quick setting time, and smooth finish.
- White Cement: Used for pointing walls, creating decorative finishes (like textured walls or patterns), exterior wall finishes, tile joint filling, and precast elements where a white color is desired (e.g., terrazzo tiles, sculptures). It is suitable for both interior and exterior applications due to its durability and water resistance after setting.
Table Summary
Here is a comparison summary:
| Feature | Plaster Coat (typically POP) | White Cement |
|---|---|---|
| Composition | Made from gypsum | Made from limestone and clay |
| Strength | Less strong | Stronger |
| Setting Time | Relatively fast | Slower than POP, but faster than grey cement |
| Flexibility | Can be moulded into shapes | More rigid |
| Water Resistance | Low (susceptible to damage) | High (durable once set) |
| Typical Use | Interior finishes, decorative work, moulds | Interior/Exterior finishes, pointing, tiles |
Practical Insights
- For purely decorative, non-load-bearing internal finishes like intricate mouldings, Plaster of Paris is often the preferred material due to its fine texture and ease of sculpting.
- When a strong, durable, and weather-resistant white finish is required on external walls or for filling tile joints, white cement is the suitable choice.
- Sometimes, white cement is used in conjunction with other materials or polymers to improve its workability or specific properties for decorative coats.
Understanding the difference in their composition and resulting properties is crucial for selecting the right material for a specific construction or decorative task.
