Plastering in Construction: Types, Process, and Best Cement for Plaster

When you walk into a well-finished house, what immediately catches your eye is the smoothness of the walls and ceilings. That seamless finish is the result of plastering, a process that does more than just beautify; it protects, strengthens, and extends the life of a building.

Many homeowners treat plastering as a routine step in construction, but it is a crucial stage that determines how walls will look and perform for years. A poorly executed plaster job can lead to cracks, damp patches, and flaking paint, while the right plaster ensures strength, durability, and a perfect base for further finishes.

In this detailed guide, we’ll explore the different types of plastering, the role of cement plastering, and how to choose the best cement for plastering work in your home.

What is Plastering and Why is it Important?

Plastering is the process of applying a paste of binding material, fine aggregates, and water over masonry or concrete surfaces. This coat can be applied to both internal and external walls.

Key Functions of Plastering:

• Surface Protection: Shields walls from rain, dust, heat, and chemical action.

• Durability: Reduces wear and tear, extending the life of the structure.

• Aesthetic Appeal: Provides a uniform, smooth finish that enhances the look of interiors.

• Base for Paints: Acts as the foundation layer before applying paint or wall treatments.

• Improved Insulation: Helps in thermal and sound insulation when applied in proper thickness.

Without plastering, exposed brickwork or blockwork may absorb moisture, develop cracks, and deteriorate faster.

Types of Plastering

Different materials have been used for plastering throughout history. While cement plaster is the most common today, other types are still relevant in specific situations.

1. Cement Plastering

The most popular and durable form, made of cement, sand, and water.

• Mix Ratios: Commonly 1:4 (stronger) or 1:6 (economical).

• Applications: Both internal and external walls.

• Advantages:

A. Strong adhesion to brick or block surfaces.

B. Water-resistant, suitable for external use.

C. Forms a solid base for paints and wall putty.

• Drawback: Requires curing for 7–10 days; if neglected, cracks may appear.

2. Lime Plastering

Used widely before cement became common. Made with slaked lime and sand.

• Features:

A. More flexible than cement plaster, reducing cracks.

B. Breathable—allows moisture to escape.

C. Smooth finish without extra polishing.

• Uses: Heritage building restoration, eco-friendly construction.

• Limitation: Lower compressive strength, not suitable for load-bearing external walls.

3. Mud Plastering

An age-old method using clay, water, and sometimes straw or cow dung.

• Advantages:

A. Cost-effective and eco-friendly.

B. Provides natural insulation.

• Drawback:

A. Not durable against rain and moisture.

B. Requires frequent maintenance.

• Common in: Rural housing, temporary or low-cost construction.

4. Gypsum Plastering

A modern alternative that has gained popularity in urban housing.

• Properties:

A. Prepared by mixing gypsum powder with water.

B. Quick setting—dries in 20–30 minutes.

C. Provides a smooth, polished finish.

• Advantages:

A. No curing required, unlike cement plaster.

B. Lightweight and fire-resistant.

• Best for: Interior walls and ceilings.

• Drawback: Not suitable for external walls exposed to moisture.

5. Special Plasters

Depending on building needs, special types like waterproof plaster, heat-resistant plaster, or acoustic plaster are also used. These are mixed with additives like waterproofing compounds, vermiculite, or fibers to enhance performance.

The Plastering Process: Step by Step

A well-applied plaster layer depends on both materials and technique.

1. Surface Preparation:

• Clean walls to remove dust, oil, or loose mortar.

• Moisten the surface to prevent water absorption from plaster.

2.Applying Base Coat:

• For rough masonry, a slurry of cement and water is applied for better adhesion.

3. Mixing the Plaster:

• Cement and sand are mixed in the required ratio.

• Clean water is added gradually.

4. Application:

• Plaster is applied in layers, starting with a base coat of 10–15mm thickness.

• For smooth finishes, multiple coats may be applied.

5. Finishing:

• The surface is leveled using a straight edge and finished with a trowel.

6. Curing:

• Cement plaster requires regular water curing for at least 7 days to gain full strength.

Best Cement for Plastering

Choosing the right cement makes all the difference in the finish and durability of plastering work.

1. Ordinary Portland Cement (OPC – 43 Grade)

• Provides high early strength.

• Suitable for external plastering where strength matters.

2. Portland Pozzolana Cement (PPC)

• Finer particles and better workability.

• Generates less heat, reducing shrinkage cracks.

• Produces smoother finishes, making it ideal for internal plastering.

3. White Cement

• Used for decorative plastering and finishing.

• Commonly used as a base for wall putty before painting.

Which One Should You Choose?

• For external plastering → OPC 43 grade is better for durability.

• For internal plastering → PPC gives a smoother finish and reduces cracks.

• For decorative work → White cement is the right choice.

Common Plastering Defects and How to Avoid Them

Even with the right cement and mix, plastering can fail if not executed properly.

• Cracks: Caused by poor curing or excess water in the mix.

• Flaking: Happens when plaster detaches due to poor surface preparation.

• Efflorescence: White patches on walls due to salts in water or sand.

• Uneven Surface: Result of improper leveling during application.

Prevention Tips:

• Always use clean, fresh cement and sand.

• Maintain proper water-cement ratio.

• Cure cement plaster thoroughly.

• Ensure the surface is rough enough for plaster to bond.

Final Thoughts

Plastering is not just the finishing step in house construction, it’s a protective shield that ensures durability and enhances aesthetics. Among the many types, cement, lime, mud, gypsum, and special plasters, cement plaster remains the most practical and widely used option.

By paying attention to the plastering process and cement choice, you can achieve walls that are not only strong but also perfectly finished.