If you’re working on home renovations or construction, you’ve probably come across the terms “screeding” and “plastering.” You might be wondering if these two processes are the same. Well, the answer is no! While both are essential in construction, screeding and plastering are quite different. In this article, we’ll dive deep into the similarities and differences between the two. By the end, you’ll know exactly when and why you need to use each process. So, let’s get started!
What is Screeding?
Screeding refers to the process of applying a smooth, level surface to a floor. This is done before the final floor covering (such as tiles or carpet) is installed. Screeding is mainly concerned with leveling out the foundation, ensuring it’s flat and solid, so the final floor installation will sit perfectly.
In simple terms, screeding is all about the foundation of your floor. It’s a crucial step that guarantees your floor doesn’t have any bumps or dips. If not done correctly, it can lead to an uneven finish for whatever floor covering you choose.
The Process of Screeding
The process of screeding involves using a mixture of sand and cement (or sometimes, other materials like self-leveling compounds) to create a smooth surface. The mixture is spread over the floor, and the screed is leveled off using a long board or tool called a “screed board.” This ensures the floor surface is perfectly flat and ready for the final finish.
Screeding can be done manually or with the help of machines, depending on the size of the area and the type of screed used.
What is Plastering?
Plastering is a process used to smooth out and cover walls and ceilings. It’s a finishing process that gives your surfaces a clean, even, and smooth look. Plastering is often the last step before painting or applying wallpaper. It helps protect the underlying structure from moisture and other damages.
Plastering can be applied to both walls and ceilings, providing a smooth surface for decoration. In many ways, it’s similar to screeding in that it’s a surface-finishing technique, but plastering is typically done on vertical or horizontal surfaces instead of floors.
The Process of Plastering
Plastering involves spreading a special plaster mix onto the walls or ceilings. This mix usually contains water, lime, and other additives that help it bind to the surface. Once applied, it’s smoothed out using a trowel to ensure an even finish.
Plastering often requires multiple layers: a base coat, followed by one or two finishing coats. After the plaster sets, it can be sanded down to achieve a perfectly smooth surface.
How Are Screeding and Plastering Different?
While screeding and plastering may seem similar at first glance, they are used for different purposes and on different surfaces. Here are the main differences:
1. Purpose and Use
- Screeding is used to create a level, smooth surface on floors. It prepares the floor for the final finish, such as tiles, carpet, or wood. It ensures there are no imperfections that could affect the final floor covering.
- Plastering is used to create a smooth, even surface on walls and ceilings. It not only prepares these surfaces for decoration but also adds a layer of protection against moisture and dirt.
2. Materials Used
- Screed is typically made from a mixture of sand and cement. Some modern screeds may contain self-leveling compounds or other additives to make the surface more stable.
- Plaster is made from a mix of lime, water, and other additives. The plaster is typically smoother and more malleable than screed, which makes it suitable for applying to vertical surfaces.
3. Surface Application
- Screeding is always applied to floors. It’s designed to be a base layer before laying flooring.
- Plastering is applied to walls and ceilings. It can be used as a finishing coat for aesthetic purposes.
4. Thickness
- Screed is generally much thicker than plaster. It is laid in a thickness of 25mm to 50mm or even more depending on the job.
- Plaster is thinner, usually around 2mm to 6mm, as it is only used to finish surfaces and provide a smooth look.
When Should You Use Screeding?
If you’re working on a floor that needs to be levelled or prepped for a floor covering, screeding is the way to go. Some specific scenarios where screeding is essential include:
- New Floor Installations: If you’re installing new floors in a room, screeding is needed to ensure the base is level.
- Floor Repairs: If the existing floor is uneven or damaged, screeding can fix these issues.
- Underfloor Heating: If you’re installing underfloor heating, screeding provides a solid, level surface to help distribute the heat evenly.
When Should You Use Plastering?
Plastering is usually used in the following cases:
- New Walls or Ceilings: When building new walls or ceilings, plastering gives them a smooth, finished look.
- Wall and Ceiling Repairs: If the walls or ceilings are damaged or uneven, plastering helps restore them.
- Aesthetic Finishing: Once a wall is built, plastering can provide a beautiful finish that is perfect for painting or wallpapering.
Can Screeding Be Used on Walls?
Screeding is generally not used on walls because it’s a thick, heavy material designed for floors. It’s not ideal for vertical surfaces due to its weight and the difficulty in keeping it in place. Instead, plastering should be used for walls to create a smooth, solid finish.
However, rendering, a type of exterior plastering, may sometimes be used on walls as a base for external finishes like paint. It’s similar to plaster but thicker and designed to withstand outdoor elements.
What Are the Common Tools Used for Screeding and Plastering?
Screeding Tools
- Screed Board: A long, straight board used to level and smooth the screed.
- Trowel: A hand tool used to apply and smooth the screed.
- Spirit Level: Used to ensure the screed is perfectly level.
Plastering Tools
- Trowel: A flat hand tool used to spread and smooth the plaster.
- Float: A flat tool used to smooth out the plaster once it’s been applied.
- Plastering Hawk: A tool that holds the plaster mix while it’s being applied to walls or ceilings.
Do You Know? Top Facts About Screeding and Plastering
- Fact #1: Screeding can be self-leveling. New technology has introduced self-leveling screeds, which can automatically smooth out and level themselves, reducing the time and effort needed.
- Fact #2: Plastering can add extra insulation to your home. Depending on the type of plaster used, it can help insulate walls and ceilings, keeping your home warmer in winter and cooler in summer.
- Fact #3: Screeding can also be done with liquid screeds that require less labor and create a smoother finish.
- Fact #4: A well-done plaster job can last for years without cracking, but it requires skill and experience to achieve the best results.
Do’s and Don’ts for Screeding and Plastering
Screeding Do’s:
- Do Use the Right Mix: Always use the correct ratio of sand and cement for screeding.
- Do Ensure a Level Subfloor: Before applying screed, ensure the base floor is as level as possible.
Screeding Don’ts:
- Don’t Rush the Drying Process: Allow the screed to cure properly before laying any flooring.
- Don’t Apply Screed Too Thin: A thin screed won’t offer the strength needed to support floor coverings.
Plastering Do’s:
- Do Apply in Thin Layers: Apply plaster in thin layers to ensure it sets properly and doesn’t crack.
- Do Work in Small Sections: Plaster in manageable sections to avoid drying issues.
Plastering Don’ts:
- Don’t Plaster Over Wet Surfaces: Ensure the surface is dry before plastering to avoid peeling.
- Don’t Skip the Preparation: Properly prepare the surface to ensure the plaster sticks and smooths out correctly.
FAQs
1. Is screeding necessary for every floor installation?
Yes, screeding is necessary if the base floor is uneven or if you’re using floor coverings like tiles or carpet.
2. Can plastering be done on both walls and ceilings?
Yes, plastering is commonly done on both walls and ceilings to achieve a smooth finish.
3. What’s the best type of plaster for wall finishing?
For wall finishing, gypsum plaster is often the best choice as it provides a smooth, durable finish.
4. Can you plaster over old paint?
It’s not recommended to plaster directly over old paint. It’s best to sand or clean the surface first to ensure proper adhesion.
5. What’s the difference between screeding and rendering?
Screeding is used for floors, while rendering is a type of plastering used for external walls.
6. How long does screeding take to dry?
Screed can take 1-7 days to dry, depending on the thickness and environmental conditions.
7. Can plastering fix cracked walls?
Yes, plastering can repair and smooth out cracked walls, provided the cracks are properly treated first.
8. Is self-leveling screed better than traditional screed?
Self-leveling screed can be more efficient, as it spreads and levels itself without much manual effort.
9. Do you need to prime surfaces before plastering?
It’s often recommended to prime surfaces before plastering to improve adhesion, especially on porous walls.
10. How thick should plaster be on walls?
Plaster on walls should be around 2-3mm thick for a smooth finish.
Conclusion
In conclusion, while screeding and plastering may seem similar, they serve different purposes and are applied in different areas of construction. Screeding is essential for creating a smooth, level foundation on floors, while plastering provides a smooth finish for walls and ceilings. By understanding the differences and the appropriate situations for each, you can ensure your home renovation or construction project goes smoothly and looks great.
Recommendation: Always consult an expert to determine whether screeding or plastering is best for your project, especially when it comes to floor and wall treatments!
