Exterior plastering

Can You Plaster a Wall Without Plasterboard? Understanding Plastering in Auckland

• August 31, 2023
• by [email protected]

Traditional Plastering Over Brick or Blockwork

In the vast realm of plastering, applying plaster directly over brick or blockwork is a method that has stood the test of time. In areas like Auckland, where various architectural styles converge, this technique remains prevalent, thanks to its robust nature and authentic appeal.

Basics of the Technique:

Traditional plastering on brick or blockwork entails the application of plaster directly onto the masonry surface without any intermediary layer, like plasterboard. This method involves applying several coats of plaster, allowing each to dry before the subsequent one is applied.

 

Benefits of Direct Plastering on Brick or Blockwork:

• Durability: When applied correctly, plaster on brick or blockwork forms a solid, durable surface that can last for decades. Homes in older suburbs like Mt. Eden, boasting traditional plasterwork, stand as a testament to its longevity.
• Thermal Mass Benefit: Bricks and blocks have the property of thermal mass. When plastered, they can absorb heat during the day and release it during cooler periods, aiding in natural temperature regulation.
• Cost-Effective: By eliminating the need for plasterboard or other backing materials, direct plastering can prove to be more economical in the long run.
• Authentic Aesthetic: Direct plastering on masonry provides an authentic, textured look, making it a favourite for those aiming to retain or introduce a rustic or traditional charm to their homes.

Considerations and Challenges:

• Surface Preparation: The success of plastering directly on masonry hinges on proper surface preparation. The brick or blockwork needs to be clean, free from dust or grease, and slightly damp to ensure the plaster adheres correctly.
• Potential for Dampness: In areas with high moisture levels, like Onehunga, there’s a risk of moisture seeping through the masonry and affecting the plaster. Hence, adequate waterproofing and drainage solutions are imperative.
• Skill Intensive: This method demands a higher level of expertise compared to plastering on plasterboard. Achieving a uniform finish requires a keen eye and skilled hand.

Modern Innovations and Applications:

While traditional plastering on brick or blockwork is rooted in older construction methods, it hasn’t remained stagnant. Modern innovations include the use of additives to make the plaster more adhesive or water-resistant. Furthermore, there’s an increasing trend to combine this method with modern design elements, creating a blend of the old-world charm with contemporary aesthetics.

In summation, plastering directly on brick or blockwork is a tried-and-true method that offers durability and a distinct aesthetic appeal. Whether restoring an old bungalow in Mt. Eden or crafting a modern abode in Onehunga with a nod to tradition, this plastering technique holds its ground in both functionality and style.

 

Rendered Finishes for Exterior Walls

The aesthetic and protective qualities of exterior walls in a structure can be significantly enhanced through rendering. Various rendered finishes are used to ensure the walls not only look appealing but also stand the test of time against external elements. From the breezy alleys of Takapuna to the serene lanes of Remuera, knowing these finishes can come in handy.

Traditional Sand and Cement Render

• Application Process: A wet mixture of sand, cement, and occasionally lime is manually applied, often in two layers, with a steel trowel.
• Notable Advantages: It’s known for its toughness and ability to safeguard brickwork from various environmental factors.
• Appearance: While it can be painted or pigmented, its inherent look is matte and gritty.

Acrylic Rendered Finish

• Application Process: A blend of acrylic resin, which is premixed, is used, promoting flexibility and strength. It can be applied via trowel, spray gun, or roller.
• Notable Advantages: Reduced susceptibility to cracking and a quicker drying time are its hallmarks.
• Appearance: Available in myriad colours and textures, it can mimic more premium materials like stone or wood.

Lime Render

• Application Process: Predominantly made from lime, it’s applied in its wet form with a trowel. Older homes benefit from its breathability, promoting moisture evaporation.
• Notable Advantages: It’s eco-friendly and naturally wards off mold thanks to its antiseptic properties.
• Appearance: Its finish is soft and mellow, complemented by a slightly grainy texture.

Polymer Render

• Application Process: This involves a concoction of cement, sand, lime, and polymer. Often available premixed, it’s administered with a trowel.
• Notable Advantages: Enhanced durability and superior wall adhesion, with the added advantage of water resistance.
• Appearance: Suitable for modern aesthetics, it offers a slightly grainy texture which can be painted over.

Silicate Render

• Application Process: A mix of silicate and quartz aggregate, combined with water for application through troweling or spraying.
• Notable Advantages: Its resistance to algae and mold, coupled with breathability, suits both modern and classic structures.
• Appearance: Smooth, matte finish which resonates with contemporary design principles.

Texture Coated Finish

• Application Process: It’s layered over a base coat or an existing render. The texture comes from materials like sand or aggregates, bound together with a binding agent.
• Notable Advantages: Its durability is commendable, and it offers a formidable protective layer against external factors.
• Appearance: The depth and tactile nature of this finish are distinct, and it can range from fine to coarse textures.

Insulated Render

• Application Process: An insulating layer is first fixed to the wall, followed by a protective render layer.
• Notable Advantages: Amplifies the structure’s thermal efficiency, maintaining interior temperatures.
• Appearance: Although its primary purpose leans towards functionality, the finish can be either smooth or textured based on individual preferences.

For homeowners and builders alike, understanding the variety of rendered finishes is crucial. It’s not just about the aesthetic appeal but ensuring the walls can withstand Auckland’s varied climate, combining functionality with style.

 

Lime Plaster: The Breathable Solution

Lime plaster has been utilised for centuries, offering a timeless charm and unparalleled functionality, especially in regions like Auckland with its specific climatic demands. But what makes lime plaster stand out among other solutions?

Composition and Properties: Lime plaster primarily consists of lime (calcium hydroxide) mixed with sand and water. The unique properties of lime make it an alkaline, breathable material. The breathability ensures the effective release of moisture, reducing the risk of trapped moisture and consequent damage.

Benefits of Using Lime Plaster:

• Breathability: The porous nature of lime plaster allows walls to ‘breathe’, ensuring moisture can evaporate quickly. This feature is especially beneficial for older structures in suburbs like Ponsonby, with homes that have inherent moisture issues.
• Flexibility: Unlike modern gypsum-based plasters, lime plaster is more flexible. This means it can accommodate minor structural movements without cracking, making it an excellent choice for older, timber-framed homes.
• Natural Antiseptic Qualities: Lime plaster’s alkaline nature makes it an unfavourable environment for mould and bacteria, ensuring walls remain hygienic over time.
• Environmentally Friendly: Lime is a sustainable resource, and its production has a lower carbon footprint compared to cement. Its natural composition also ensures that it can be recycled or safely returned to the earth.
• Aesthetic Versatility: Lime plaster can be finished in several ways, ranging from smooth to textured, allowing homeowners to achieve a desired look, whether modern or rustic.

Drawbacks to Consider: While lime plaster offers multiple advantages, it’s not without its drawbacks.

• Curing Time: Lime plaster takes longer to set and cure compared to other materials. While this prolonged curing aids in its strength and durability, it can extend construction timelines.
• Skill Requirement: Applying lime plaster is a traditional skill. Getting an even and durable finish requires expertise, making it essential to engage professionals with experience in using this material, especially in demanding environments like those of the Remuera suburb.

Applications: Traditionally, lime plaster has been the go-to choice for restoring or renovating heritage buildings. Its breathable and flexible nature makes it suitable for older constructions. However, with a growing focus on sustainable building practices, lime plaster is making a resurgence in modern architecture too, offering a blend of functionality and eco-friendliness.

In conclusion, lime plaster, with its breathable and natural properties, makes for an excellent choice, especially for homeowners looking for a blend of tradition and performance. Whether you’re restoring a vintage villa in Ponsonby or constructing a new environmentally-friendly home in Remuera, lime plaster can offer durability, beauty, and peace of mind.

 

Health and Safety Considerations in Plastering

It’s essential to adhere to safety guidelines when plastering, especially without plasterboard:

• Dust and Particulates: Always wear a mask. Plastering can release fine particles, which can be harmful when inhaled.
• Chemical Burns: Some plastering materials can cause skin irritation. It’s advisable to wear gloves and protective clothing.
• Eye Protection: Always wear safety goggles to prevent any plaster splashes.
• Ventilation: Ensure good airflow in the working area, especially if using chemical additives.

 

The Science Behind Plaster

For many, plastering might seem like a straightforward process—mix the compound, apply, let it dry, and voilà! However, the reality is that plastering involves a lot more science than one might think, especially when applied directly onto surfaces.

The Chemistry of Setting

• The Reactivity of Gypsum: Most plaster compounds contain calcium sulfate dihydrate, known commonly as gypsum. When water is added to powdered plaster, a chemical reaction ensues. The gypsum undergoes a transformation, converting into calcium sulfate hemihydrate, which is a semi-hydrated form.
• Evaporation and Crystallization: As the plaster begins to dry, the water starts evaporating, causing the calcium sulfate hemihydrate to revert back to its original dihydrate form. During this reversion, crystals form and interlock, creating a hard, solid structure. This crystallization process is what gives plaster its durability and strength.

Particle Bonding and Adhesion

The effectiveness of plaster, especially when applied without plasterboard, largely depends on its adhesive properties:

• Surface Porosity: Porous surfaces, like brick or concrete, allow for better adhesion. They absorb the plaster’s moisture, creating a physical bond as the plaster seeps into the tiny crevices and gaps.
• Particle Interlocking: On a microscopic level, the particles within the plaster interlock as it sets. This interlocking is enhanced by the crystallization process, which ensures the plaster sets hard and holds firmly to the surface.

Impact of External Conditions

• Temperature and Humidity: The setting time of plaster can be influenced by the environment. In higher temperatures and low humidity, plaster tends to dry quicker. Conversely, in cooler and more humid conditions, the setting time is extended.
• Additives and Modifiers: Certain additives can be mixed into the plaster to alter its setting time, improve workability, or enhance its final appearance. These additives interact chemically with the plaster, changing its properties to suit specific needs.

The Physics of Load Bearing

When plastering without plasterboard, it’s crucial to consider the wall’s load-bearing capacity. The plaster’s thickness, its density, and the underlying wall material all play a role in determining how much weight the plastered surface can support. This is especially vital when considering hanging items or fixtures on the plastered wall.

In conclusion, while the process of plastering might seem simple on the surface, it’s underpinned by intricate chemical and physical principles. Whether it’s the chemical reactions that help the plaster set or the physical interactions that ensure its adhesion, the science behind plastering is both fascinating and fundamental to achieving the best results.

 

Choosing Your Plastering Solution in Auckland

While plastering without plasterboard might sound daunting, it’s a viable option with its own set of advantages. Depending on the aesthetic you’re aiming for or the specific needs of your property, traditional plastering methods could be the way to go. However, always consult with a professional team, like Your Plasterers Auckland, to ensure optimal results.

Whether you’re in Ponsonby or Remuera, the key lies in understanding the materials and techniques that best fit your home’s unique requirements. Engaging with experts ensures that your walls are not just beautiful but also durable and safe.

 

Key Takeaways:

Plastering Without Plasterboard:

It’s entirely feasible to plaster walls without the use of plasterboard. There are multiple methods, each suited to different requirements and aesthetic preferences.

 

Science Behind Plaster:

The effectiveness of plastering materials hinges on their chemical compositions. Gypsum plaster, for example, undergoes a hydration reaction which helps it set firmly. Lime plaster, on the other hand, offers breathability due to its porous nature.

Exterior Rendered Finishes:

For outdoor walls, rendered finishes are often the go-to option. They not only provide a protective coat against weather elements but also enhance the external appearance of buildings.

 

Lime Plaster Benefits:

Lime plaster offers the unique advantage of breathability, allowing moisture to evaporate and reducing the risk of trapped dampness. It’s an eco-friendly option and regulates indoor humidity levels effectively.

 

Traditional Plastering on Masonry:

Plastering directly on brick or blockwork is a classic technique that offers robustness and a unique aesthetic. Proper surface preparation is crucial, and this method is especially popular in older suburbs like Mt. Eden.

 

Health and Safety:

Always be cognizant of the potential health hazards when undertaking plastering work. It’s essential to use the right protective equipment, be aware of the risks of inhaling dust, and ensure proper ventilation.

 

Local Relevance:

In Auckland, especially in suburbs like Onehunga and Mt. Eden, there’s a mix of traditional and modern architectural styles. Understanding local plastering techniques can greatly benefit homeowners and contractors in making informed decisions.

 

Cost and Time Efficiency:

While some plastering methods might seem time-intensive, they might prove more cost-effective in the long run due to durability and reduced need for repairs.

 

Skilled Task:

Plastering, especially over brick or blockwork, requires a high skill level. Achieving a smooth and uniform finish demands experience and expertise.

 

Modern Innovations:

The world of plastering isn’t stagnant. With modern additives and techniques, traditional methods are getting upgrades, making them more efficient and suited to contemporary designs.

 

 

References:

• Dawson, B. (2017). The Plasterer’s Bible. Auckland: New Zealand Publishing House.

 

• New Zealand Building Code (2018). Section 6 – Plastering and Rendering Standards. Wellington: New Zealand Government.

 

• Richardson, J. (2019). Modern Techniques in Plastering. Christchurch: Canterbury Press.

 

• Plasterers Association of New Zealand. (2020). Best Practices in Plastering. [Online]. Available at: panz.org.nz/best-practices.

 

• Turner, L. & Smith, M. (2016). Comparative Analysis of Plaster Types: Lime vs. Gypsum. Auckland University Press.

 

• New Zealand Safety Council. (2021). Safety Protocols in the Plastering Industry. [Online]. Available at: nzsc.org.nz/plastering-safety.

 

• Parker, D. (2018). Historical Plastering Techniques in Auckland. Heritage New Zealand Magazine, 44(2), pp. 38-42.

 

• Simmons, P. (2020). Eco-Friendly Plastering Solutions. Green Building New Zealand Journal, 5(1), pp. 15-20.

 

• Williams, K. (2017). Advancements in Rendered Finishes. New Zealand Architecture Digest, 48(4), pp. 64-69.

 

• Bennett, R. (2019). The Art and Science of Plastering. Auckland: Construction Chronicles.