Plaster vs render: What’s the difference?

Knowing the difference between plaster vs. render is essential for anyone tackling a construction or renovation project. Failing to grasp this distinction can lead to suboptimal outcomes, wasted time, and unnecessary expenses. This article aims to clarify render vs. plaster techniques, their applications, and when to use each one, helping you make informed decisions for your next project.

What is plastering and when should you get plastering help?

Plastering is the process of applying a smooth, durable finish to interior walls and ceilings. It involves spreading a mixture of lime, cement, sand, and water onto surfaces to create a seamless, flat finish. Plaster is commonly used for:

• Smoothing rough interior walls
• Repairing damaged drywall
• Creating decorative finishes
• Improving sound insulation

Common types of plaster include gypsum, lime, and cement plaster. Each type has specific properties suited to different applications and environmental conditions.

Plastering typically costs $20 to $90 per square metre, depending on the type of plastering work. More complex or ornamental plastering can cost up to $85 or more. Many plasterers also offer daily rates at around $240 or higher or hourly rates at $50 or more. Plastering costs can vary based on factors like job complexity, location, and the plasterer’s experience, so it’s advisable to obtain multiple quotes for accurate pricing.

What is rendering and when should you get rendering help?

Rendering is the application of a cement-based rendering mixture to external walls to create a protective and decorative finish. It provides a durable, weather-resistant surface that can enhance a building’s appearance and improve its structural integrity. Render is typically used for:

• Weatherproofing exterior walls
• Improving thermal insulation
• Enhancing curb appeal
• Protecting brickwork or masonry

There are various types of render, including traditional cement render, lime, and modern acrylic or polymer-modified renders. Each type offers different benefits in terms of durability, flexibility, and aesthetic options.

Since rendering is more expensive than plastering, it’s recommended that you use the services of a qualified plasterer to complete rendering work for your home. It takes a skilled hand to achieve professional results.

Plaster vs. render: Which one applies to your needs?

If you’re wondering whether it’s better to use plaster vs. cement render for filling walls, here’s a breakdown of each.

Material mixture and composition

Plaster typically consists of gypsum, lime, or cement mixed with water. This composition results in a softer, more porous material suitable for interior use. It contains less cement than render since it merely coats the interior walls and ceilings of buildings to prep them for painting or wallpapering.

Render, on the other hand, is made from cement, lime, sand, and water, creating a harder, more weather-resistant mixture ideal for exterior applications. Depending on the render, some key ingredients give it its definition; for example, lime gypsum gives the coating a creamy appearance, while finer sand can create a smooth finish.

Plaster composition allows for a smoother finish and better sound insulation, while the render’s robust mixture provides superior weather protection and durability against the elements. The material choice affects not only the appearance but also the lifespan and maintenance requirements of the entire surface.

Application techniques

Plastering typically involves three layers: a base coat, a second coat, and a finish coat. Each layer is applied with trowels and allowed to dry before the next is added. The process requires skill to achieve a perfectly smooth surface.

Plaster must be set and completely dry before painting the walls. A freshly plastered wall can take at least a week and up to a month to dry. You can tell when the plaster is completely dry when there are no dark patches visible, and the coating is light and even.

On the other hand, rendering usually involves applying one or two coats to exterior walls using a trowel or spray equipment. A workman may then finish it with different tools depending on the homeowner’s desired appearance—either a smooth, flat finish or with a texture or pattern. Also, some modern renders can be applied in a single coat, saving time and man-hours.

Durability and maintenance

Plaster, being an interior finish, is less at risk of harsh conditions, but it can still be prone to cracking due to building movement or moisture issues. Regular painting and prompt repair of any cracks or chips can extend its lifespan.

Meanwhile, the render is exposed to the elements. While it’s certainly more durable, it requires proper maintenance to prevent issues like cracking or water ingress. Regular cleaning, repainting every 5 to 10 years, and addressing any cracks promptly can ensure that the render remains effective and attractive for decades.

Important note: Before undertaking any plastering or rendering work on older buildings (particularly those built from the 1930s to the 1970s), have the surfaces checked for asbestos. Consult a licensed asbestos professional if you suspect its presence.

Function and uses

Plaster is primarily used for internal walls and ceilings, providing a smooth, even surface that’s ideal for painting or decorative finishes. It’s excellent for creating intricate mouldings and ornamental features.

Render is used to coat external walls, both for protection and decoration. It shields the underlying structure from weather damage, improves thermal insulation, and can significantly enhance a building’s superficial appeal. Render is particularly useful for covering imperfections in brickwork or concrete surfaces or mending exterior walls’ cosmetic defects.

Sustainability and environmental impact

Both plaster and render have environmental implications. Traditional plaster and render mixes can generate significant waste and have a high carbon footprint due to cement production. However, the industry is moving towards more sustainable practices.

Eco-friendly alternatives like clay plasters and lime renders are gaining popularity. These materials have lower embodied energy, are often locally sourced, and can be recycled. Some innovative products incorporate recycled materials or industrial by-products, reducing waste and environmental impact.

Proper application techniques can minimise waste, and some companies now offer recycling services for leftover materials. Additionally, well-maintained plaster and render can contribute to a building’s energy efficiency, potentially offsetting its initial environmental cost over time.

Beyond the surface: rendering vs. plastering

Understanding the difference between render and plaster is crucial for any home improvement or building project. Both techniques serve unique purposes, with plaster enhancing interiors and render protecting exteriors. 

For the best results, consult a qualified plasterer or renderer who can assess your specific needs and provide expert advice tailored to your project. With the right application, you’ll achieve a stunning and durable finish that stands the test of time.

Ready to give your walls a refresh? Post a job on Oneflare and connect with top-rated plasterers or renderers near you.

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FAQs on plastering vs rendering

Do plasterers do rendering?

Not all plasterers do rendering. Plastering and rendering are distinct trades, though some professionals are skilled in both. Plasterers primarily focus on interior work, applying plaster to walls and ceilings. Renderers specialise in exterior finishes, applying cement-based mixtures to outside walls.

If you need rendering done, it’s best to look for a skilled professional in that specific field. Always check their experience and qualifications for the specific job you need.

Is solid plastering the same as rendering?

Solid or hard plaster vs. render are similar techniques, but they’re not the same.

Solid plastering refers to the application of plaster directly onto brick, concrete, or stone surfaces, usually for interior walls. Rendering, on the other hand, is specifically the application of a cement-based mixture to exterior walls. Both techniques create a smooth surface, but rendering is designed to withstand outdoor elements and often has a coarser texture than solid plastering.

Can you plaster over a rendered wall?

It’s generally not recommended to plaster directly over a rendered wall. Render is designed for exterior use and has properties different from interior plaster.

If you’re looking to smooth out a rendered interior wall, it’s better to apply a skim coat of plaster rather than a full plastering job. For exterior walls, if you want to change from render to plaster, you’d need to remove the render first.

Always consult a professional before attempting to plaster over render, as improper application can lead to adhesion problems and a poor finish.