The main difference is that plaster is a general term for a building material used to coat walls and ceilings, while gypsum plaster is a specific type of plaster made from gypsum.
Understanding Plaster
Plaster is a broad category of building materials applied wet and allowed to harden to a rigid solid. It's traditionally used to create smooth surfaces over rough construction like brick or blockwork, or for decorative purposes. Different types of plaster are distinguished by their main binding agent.
Common types of plaster include:
- Lime Plaster: Made from calcium hydroxide (lime) and sand.
- Cement Plaster (Mortar Plaster): Made from cement, sand, and water. Often used for external rendering or as a base coat.
- Gypsum Plaster: Made from calcium sulfate hemihydrate (gypsum).
What is Gypsum Plaster?
Gypsum plaster is specifically produced by heating gypsum rock. This process removes water, creating a powder that, when mixed with water, rehydrates and sets. This unique composition gives it distinct properties compared to other plasters like traditional sand-cement mortar plaster.
Key Differences and Advantages of Gypsum Plaster
Based on the provided reference and general knowledge, gypsum plaster offers several advantages, particularly when compared to traditional mortar plaster:
- Composition: The fundamental difference lies in the binder – gypsum for gypsum plaster versus cement (or lime) for other types.
- Effectiveness: Gypsum plaster is more effective for internal wall and ceiling finishes.
- Shrinkage Cracks: One of the most significant advantages is that gypsum plaster suffers from few to no shrinkage cracks during drying and setting, unlike cement-based plasters which are prone to cracking as they cure.
- Application & Finish: Applying gypsum plaster results in perfectly lined and leveled walls easily. Achieving a smooth finish requires a lot of labor with mortar plaster, whereas gypsum plaster inherently helps create smooth, high-quality finishes with relative ease.
- Aesthetics: The smooth, seamless finish achievable with gypsum plaster helps create visually appealing living rooms with ease.
- Setting Time: Gypsum plaster typically sets faster than cement plaster, speeding up construction.
- Weight: Gypsum plaster is generally lighter than cement plaster, reducing the structural load.
- Fire Resistance: Gypsum has natural fire-resistant properties due to the water content within the gypsum crystals.
Comparing Gypsum Plaster vs. Mortar Plaster
Here's a table summarizing some key differences, highlighting points from the reference:
| Feature | Gypsum Plaster | Mortar (Cement) Plaster |
|---|---|---|
| Main Binder | Gypsum (Calcium Sulfate Hemihydrate) | Cement (Portland Cement), Sand, Water |
| Effectiveness | More effective for internal finishes | Standard for external/internal base |
| Shrinkage | Few to no shrinkage cracks | Prone to shrinkage cracks |
| Smoothness | Easily achieves perfectly lined/leveled surfaces | Requires a lot of labor for smoothness |
| Application | Faster setting, easier to finish smoothly | Longer setting time, requires skilled finishing |
| Weight | Lighter | Heavier |
| Aesthetics | Helps create visually appealing finishes easily | Requires more effort for high-quality finish |
In essence, while plaster is the family name for wall coatings, gypsum plaster is a modern, specialized member known for its superior finish, ease of application, and resistance to cracking, making it a preferred choice for internal surfaces compared to traditional mortar plaster.
