Do you intend to apply a new, sleek coating on your walls? If so, you might be wondering: what goes into plastering for that professional finish?
Plastering involves a series of carefully executed steps, and understanding the stages of the process will help you achieve a flawless result.
Whether you’re tackling a DIY renovation or hiring a professional, knowing the stages of plastering is essential for ensuring a smooth, durable, and aesthetically pleasing finish.
In this article, we’ll walk through each stage of plastering, with an emphasis on Australian conditions and techniques, highlighting important tips and expert advice to help you get the best results.
Let’s get straight to the point
Plastering involves several stages to achieve a smooth and durable finish.
Key steps include preparation (cleaning, sealing cracks, adjusting suction), applying a base or scratch coat, followed by a floating coat to fill irregularities.
The surface is then smoothed, trowelled, and polished for a refined finish. Plastering offers aesthetic appeal, durability, fire resistance, and pest control benefits.
In Australia, plasterboard finishes range from Level 3 (basic) to Level 5 (premium), depending on the lighting and quality requirements. Proper plastering improves both the look and function of walls.
What Is Plastering?
Plastering is the process of applying layers of plaster to walls or ceilings to create a smooth surface that can be painted, wallpapered, or left as is.
Plastering not only enhances the aesthetic appeal of your space but also adds durability, improves sound insulation, and can even provide fire resistance.
Before diving into the stages of plastering, let’s break down some of the key types of plaster commonly used in Australia:
- Cement plaster: Typically used for exterior walls, it offers strength and durability.
- Gypsum plaster: Known for its smooth finish, this is often used indoors.
- Lime plaster: Historically popular in Australia, it’s breathable and ideal for heritage properties.
Stages of Plastering
1. Preparation Stage
The first and most important step in plastering is preparation. A well-prepared surface ensures a longer-lasting and more aesthetically pleasing finish.
Surface Cleaning and Inspection
Before applying any plaster, clean the surface to remove dust, grease, or loose debris. In older Australian homes, you may also need to inspect for mould, cracks, or water damage.
Sealing Cracks and Gaps
Make sure to fill and seal any cracks or crevices in the wall. Not only does this step create a smooth base, but it also helps in pest control, as plastering over cracks can prevent pests from entering your home.
Adjusting Suction
Walls with high suction rates can cause plaster to dry too quickly. In this stage, it’s crucial to adjust the suction of the surface by dampening it with water or applying a bonding agent. This ensures the plaster has enough time to properly adhere.
2. Application of the Base or Scratch Coat
The second stage involves applying the first layer of plaster, known as the base coat or scratch coat.
This layer is fundamental as it provides a solid foundation for subsequent layers.
Mixing the Plaster
Properly mixing the plaster is crucial. Ensure a smooth and lump-free consistency by mixing thoroughly.
In Australia, where climate conditions can vary, adjusting the water-to-plaster ratio is important, especially in humid areas like Queensland.
Applying the Scratch Coat
The base coat should be approximately 2-3 mm thick. Using a trowel, apply the plaster in long, sweeping motions.
Hold the leading edge of the trowel at an angle to create a smooth surface. This layer doesn’t have to be perfectly smooth; any ridges will be covered in later stages.
3. Floating Coat
Once the scratch coat has partially dried, the next stage is the floating coat, also known as the second layer.
Filling Irregularities
The floating coat helps to fill in any irregularities from the first coat, ensuring a flat and even surface.
This layer is thinner, around 1.5 mm, and is applied using a firm hand with the trowel. Apply firm pressure to eliminate bumps, but don’t worry if small holes are left behind—those will be addressed later.
4. Smoothing the Surface
At this stage, the plaster is still tacky but not fully set. This is the perfect time to smooth the surface and patch any holes or imperfections.
Eliminating Bumps and Filling Holes
Run your trowel over the surface with gentle but firm pressure, keeping the trowel at a 10-15 mm angle from the wall.
Fill in any visible holes and use additional plaster to smooth out irregularities. It’s important to complete this step before the plaster fully dries, as this will make it easier to achieve a smooth finish.
5. Final Trowelling
In the final stages, the plaster should be nearly set but still malleable. Now is the time to give your wall a perfect, polished look.
Firm Trowelling
At this stage, use a clean trowel and firmly press the plaster down, eliminating any remaining bumps or ridges. The key is to apply pressure evenly to avoid disturbing the plaster.
Watching for Darkening
As the plaster dries, it will begin to darken. Continue to work the plaster during this period, pressing down to create an even, seamless surface.
6. Final Finishing Touches
The last stage of plastering involves giving the wall its final texture and gloss.
Polishing the Surface
Once the wall is completely dry, run your trowel over the wall one last time to polish it. This will give the surface a smooth, professional finish that’s ready for painting or wallpapering.
Benefits of Plastering
Plastering is a popular choice in Australian homes for several reasons:
Aesthetic Appeal
A well-applied plaster finish creates a smooth, uniform surface that can be painted or decorated to suit any design style. It elevates the look of your interior, giving walls a more refined and polished appearance.
Durability
Plaster is highly durable and can protect walls from daily wear and tear. In high-traffic areas like hallways and kitchens, plastering can help prevent damage from knocks and scrapes.
Pest Control
Sealing cracks during the plastering process can help keep out pests like insects and rodents. By eliminating their potential entry points, you’re creating an additional defensive barrier for your home.
Fire Resistance and Insulation
Plaster is naturally fire-resistant and can provide added protection in case of a fire. It also has thermal insulation properties, helping to regulate indoor temperatures and potentially reducing energy costs.
What are the Finish Levels for Plasterboard?
In Australia, understanding the levels of finish for plasterboard is crucial when considering different interior finishes. These levels, as set by the Australian Standards (AS/NZS 2589), define the smoothness and quality required for plasterboard in different areas of a home.
Level 3 Finish
This is the basic finish for plasterboard, suitable for areas where there will be no critical lighting. It’s ideal for garages or storage spaces where appearance isn’t a major concern.
Level 4 Finish
This is the standard finish used in most homes. It is smooth and suitable for painting or wallpapering, making it the most common choice for residential interiors.
Level 5 Finish
This is a premium finish used in high-end projects where lighting conditions are harsh, such as feature walls or rooms with large windows. A Level 5 finish ensures no visible imperfections, providing a flawless result.
Conclusion
Plastering is an intricate process, but when done correctly, it results in a beautifully finished wall that can enhance any space.
From preparation to the final polish, each stage is crucial in ensuring a smooth and durable finish.
Whether you’re a DIY enthusiast or hiring a professional plasterer in Australia, following these stages will help you achieve that perfectly polished look.
Remember, patience and practice are key. A properly plastered wall not only improves aesthetics but also provides long-lasting durability, fire resistance, and even helps with pest control.
Frequently Asked Questions
Can I Plaster Over Existing Wallpaper Or Paint?
It is generally not recommended to plaster directly over existing wallpaper or paint. For a proper plastering job, it is important to have a clean and stable surface. Wallpaper and paint may prevent the plaster from adhering well to the wall and can lead to peeling or cracking in the future. It is best to remove the wallpaper or paint, repair any damage to the wall, and then proceed with the plastering process on a clean substrate.
Is It Necessary To Hire A Professional For Plastering, Or Can It Be Done As A Diy Project?
Plastering can be a challenging task that requires skill, experience, and knowledge of the proper techniques. While some small-scale plastering repairs or touch-ups can be done by individuals with DIY skills, larger projects or those involving extensive plastering work are best left to professionals. Hiring a professional plasterer ensures that the job is done efficiently, with a high level of craftsmanship, and reduces the likelihood of costly mistakes or subpar results.
How Long Does Each Stage Of Plastering Take?
The duration of each stage in plastering can vary depending on factors such as the size of the wall, the complexity of the project, and the experience of the plasterer. As a rough estimate:
- Surface preparation: This stage can take a few hours to a day, depending on the condition of the wall and the extent of repairs needed.
- Base coat application: Applying the base coat typically takes a day or two, allowing sufficient time for drying before the next stage.
- Skim coat application: Applying the skim coat usually takes a day, but it may require additional time for drying and any necessary touch-ups.
- Sanding and polishing: This stage can take a day or two, depending on the desired smoothness and perfection of the finish.
- Priming and painting: Priming usually takes a day to dry, and painting can take an additional day or more, depending on the number of coats and the drying time between them.
Is It Necessary To Remove Old Plaster Before Applying A New Layer?
In some cases, it may be necessary to remove old plaster before applying a new layer. This is particularly true if the existing plaster is damaged, loose, or compromised in any way. Removing the old plaster allows for a clean and stable base for the new plaster layer, ensuring better adhesion and durability. However, if the existing plaster is in good condition and properly adhered to the wall, it may be possible to apply a new layer of plaster directly on top after proper cleaning and preparation.
Can Plastering Be Done On External Surfaces?
Plastering can be done on external surfaces, but it requires specific materials and techniques to withstand weather conditions and provide adequate protection. External plastering often involves using specialized mixes, additives, and surface sealants that are designed to be more durable and resistant to moisture, temperature changes, and environmental factors. It is important to consult with a professional or specialized contractor to ensure the correct application and longevity of external plastering.
