What’s The Difference Between Cement Render And Plaster?

If you’re interested in having cement render applied to your home or building, you may be wondering what the difference is between plastering and the application of cement render. There are many similarities between the two, so this subject can be quite confusing.

So, in this article, the team at Zaks Render will help you understand the differences between cement render and plaster.

What is Render?

Render refers to a plaster-like material that is applied to the exterior of a building to provide a smooth, even surface. Render can be made from a variety of materials, including cement, lime, and acrylic, and is often reinforced with fibreglass or other materials to increase its strength and durability. The purpose of render is to protect the underlying brick or blockwork from the elements and to improve the aesthetic appearance of the building. Render can be coloured or textured to achieve a variety of finishes, and is a popular choice for both new construction and renovation projects.

Rendering VS Plastering – Interiors Are Plastered, Exteriors Are Rendered

This is the key difference. Interiors are usually finished using plaster, while exteriors surfaces use cement render. While the basic composition of both render and plaster are fairly similar – a combination of cement, sand and water – sometimes, the actual products are quite dissimilar.

Finer sand is used to achieve a smoother finish and smoother surfaces in internal plastering, and usually less sand is used overall. When applied to a flat surface, the coat of plaster is giving an extremely smooth finish, so it’s perfect for interior wall surfaces.

Cement rendering involves a much higher proportion of sand for additional strength. The sand is also usually much more coarse, which helps increase the strength of the cement render. The render finish coat is, correspondingly, a bit more rough and “rustic.” It’s ideal for exteriors – but the rougher appearance is not appropriate for most internal walls and ceilings. Mortar coatings like cement render are specifically formulated for exterior walls to provide durability.

Related article: What type of render should I use? Cement or acrylic?

Cement Render Is Made Specifically For High Strength And Weather Resistance

The other major difference between plaster vs cement based render is that most premixed renders come with special compounds and polymers which enhance their strength and water resistance. These additives also usually help the render resist chipping or develop cracks from impacts.

Because plaster is not exposed to exterior conditions, these additives are not present in interior plastering products. Plaster materials are designed to provide a smooth surface for decorating and do not require the same weather resistance as cement render.

What Are The Benefits Of Cement Render?

So, should you use cement render to renovate your older buildings? Applying render to your home can have a number of great benefits. If you have a home with stone or brick walls, cement render is a great way to restore its appearance if the underlying structure has become weathered or unsightly.

There are also a huge number of different finishes available. From smoother render that uses fine sand, to render with exposed pebbles and coarse sand, as well as other styles, you can always find a cement render that will make your home look beautiful.

Cement render is also extremely durable and tough and can help protect the underlying building structure from the elements, when properly applied. It’s waterproof and fire resistant, and it provides another layer of insulation – which could help lower your energy bills.

Common Mistakes to Avoid When Rendering or Plastering

Whether you’re tackling a renovation project or overseeing new construction, getting the application right is just as important as choosing the right material. Even the best-quality cement render or plaster can fail if it’s not applied correctly. Here are some of the most common mistakes homeowners and contractors make, and how to avoid them.

1. Using the Wrong Product for the Surface

One of the most frequent errors is using interior plaster on exterior walls, or vice versa. As we’ve covered above, plaster and cement render are formulated for very different environments. Applying plaster to an exterior surface exposes it to moisture and weather conditions it simply isn’t designed to handle, leading to premature cracking, bubbling, and deterioration. Always make sure you’re using the right product for the right surface.

2. Skipping Surface Preparation

Proper surface preparation is the foundation of a long-lasting render or plaster job. Applying render to a dirty, dusty, or overly smooth surface can prevent it from bonding correctly, causing it to peel or fall away over time. Before any application, ensure the surface is:

• Clean and free of dust, grease, or loose debris
• Structurally sound with no crumbling areas
• Treated with a bonding agent where necessary to improve adhesion

3. Applying Coats That Are Too Thick

It can be tempting to try to build up a finished surface in a single, thick coat to save time. However, applying render or plaster too thickly in one go significantly increases the risk of cracking as the material dries and shrinks. For best results, work in thin, even layers, allowing each coat to cure properly before applying the next.

How Many Coats Should You Apply?

As a general guide:

• Cement render typically requires 2–3 coats: a scratch coat, a base coat, and a finish coat
• Plaster is usually applied in 2 coats: an undercoat and a finishing coat

4. Not Accounting for Weather Conditions

Cement render is particularly sensitive to extreme weather during application and curing. Applying render in direct sunlight or high temperatures can cause it to dry too quickly, resulting in surface cracks. Equally, rendering in cold or freezing conditions can prevent the material from curing properly. Aim to work during mild, dry weather conditions, and protect freshly applied render from direct sun or rain where possible.

5. Neglecting to Cure the Render Properly

Curing is a critical step that is often overlooked. After application, cement render needs adequate time and moisture to cure and reach its full strength. Allowing it to dry out too quickly especially in hot or windy conditions can weaken the final surface.

Tips for Proper Curing

• Lightly mist the render with water during the first few days after application
• Avoid applying render in direct sunlight or strong wind
• Allow a minimum of 24–48 hours between coats before proceeding

6. Attempting a DIY Job Without the Right Experience

While there are plenty of DIY guides available online, cement rendering and plastering are skilled trades that take years to master. Poor application can result in an uneven finish, structural weaknesses, and costly repairs down the line. For anything beyond minor touch-ups, it’s always best to call in a professional rendering team (like the experts at Zaks Render) to ensure the job is done right the first time.

Interested In Learning More? Contact Zaks Render Right Away!

Now that you know the difference between rendering and plastering, are you curious to learn more? Zaks Render is the leading cement rendering company in Sydney. We have experience with rendering projects of all types – and we can perform both exterior rendering and interior plastering. If you’d like to see some of our work, check out our past projects now.

We understand the importance of using only the highest quality rendering materials to ensure that our clients receive the best possible results.

Want to learn more about the benefits of cement render, and get a quote for your home or building? Contact us online now, or give us a call at  0402 283 119. We’re always happy to hear from potential customers!

Cement render provides a durable alternative to paint or wallpaper on exterior walls. It is weather resistant and provides insulation.