Internal rendering is a technique used to improve the aesthetics and functionality of interior walls. Whether you’re renovating an old home or enhancing a new one, internal rendering can provide a smooth, durable, and attractive finish. This comprehensive guide will take you through everything you need to know about internal rendering, from benefits and materials to techniques and maintenance.
What is Internal Rendering?
Definition and Purpose
Internal rendering involves applying a layer of plaster or other material to the interior walls of a building. The primary purpose is to create a smooth, even surface that can be painted or decorated. Internal rendering also improves insulation, soundproofing, and structural integrity.
History and Evolution
The practice of rendering dates back thousands of years, with ancient civilizations using mud and lime plasters to finish their walls. Over time, techniques and materials have evolved, leading to the modern internal rendering methods used today.
Benefits of Internal Rendering
Enhanced Aesthetics
Internal rendering creates a smooth, uniform surface that enhances the visual appeal of any room. It allows for a variety of finishes, from sleek and modern to textured and rustic, giving you the flexibility to match your interior design style.
Improved Insulation
A significant benefit of internal rendering is its ability to improve thermal insulation. The additional layer of material helps retain heat during the winter and keep interiors cool in the summer, leading to more energy-efficient homes.
Soundproofing
Internal rendering also enhances soundproofing by adding mass and density to the walls. This reduces the transmission of noise between rooms, creating a quieter and more comfortable living environment.
Increased Durability
Rendered walls are more durable and resistant to wear and tear. The protective layer prevents damage from impacts, moisture, and other environmental factors, extending the lifespan of your interior walls.
Versatility
Internal rendering is suitable for a wide range of substrates, including brick, stone, concrete, and timber. This versatility makes it an ideal choice for both new builds and renovation projects.
Types of Internal Rendering Materials
Cement Render
Characteristics
Cement render is a mixture of cement, sand, and water. It is known for its strength and durability, making it suitable for high-traffic areas and surfaces that require extra protection.
Applications
Cement render is commonly used in basements, kitchens, and bathrooms due to its resistance to moisture and mould. It provides a hard, smooth finish that can be painted or left as is for a minimalist look.
Lime Render
Characteristics
Lime render is made from lime, sand, and water. It is a more breathable material compared to cement render, allowing moisture to escape from the walls. This prevents damp issues and promotes a healthier indoor environment.
Applications
Lime render is often used in historic buildings and renovations where breathability is essential. It creates a soft, textured finish that adds character and charm to interiors.
Gypsum Plaster
Characteristics
Gypsum plaster is a popular choice for internal rendering due to its smooth finish and ease of application. It sets quickly and provides a surface that is ideal for painting or wallpapering.
Applications
Gypsum plaster is suitable for most interior walls, including living rooms, bedrooms, and hallways. It is less resistant to moisture, so it is not recommended for bathrooms or kitchens.
Clay Plaster
Characteristics
Clay plaster is a natural, eco-friendly material made from clay, sand, and water. It is breathable, non-toxic, and provides excellent thermal and acoustic insulation.
Applications
Clay plaster is ideal for sustainable building projects and homes with a focus on natural materials. It creates a warm, earthy finish that enhances the aesthetic appeal of interiors.
Acrylic Render
Characteristics
Acrylic render is a synthetic material that includes acrylic resins. It is flexible, crack-resistant, and comes in a variety of colours and textures.
Applications
Acrylic render is suitable for both new and existing buildings. It can be applied over a range of substrates and is particularly useful for surfaces that experience movement or are prone to cracking.
Preparing for Internal Rendering
Assessing the Surface
Before starting the rendering process, it is crucial to assess the surface of the walls. Check for any damage, such as cracks, holes, or damp patches, and repair them accordingly. Ensure the surface is clean, dry, and free from dust and debris.
Choosing the Right Materials
Selecting the appropriate rendering material is essential for achieving the desired finish and performance. Consider factors such as the type of substrate, the room’s function, and your aesthetic preferences when choosing materials.
Gathering Tools and Equipment
Having the right tools and equipment is vital for a successful rendering project. Common tools include trowels, hawks, mixing buckets, plastering floats, and brushes. Ensure you have all the necessary safety gear, such as gloves, goggles, and dust masks.
Protecting Surrounding Areas
Protect surrounding areas, such as floors, windows, and furniture, from dust and splashes during the rendering process. Use drop cloths, plastic sheeting, and masking tape to cover and secure these areas.
Step-by-Step Guide to Internal Rendering
Surface Preparation
Cleaning and Repairing
Thoroughly clean the walls to remove any dirt, grease, or loose material. Repair any cracks or holes with filler and sand the surface to create a smooth base for rendering.
Applying a Bonding Agent
Apply a bonding agent to ensure the render adheres properly to the wall. This is especially important for smooth or non-porous surfaces. Follow the manufacturer’s instructions for application and drying times.
Mixing the Render
Preparing the Mix
Mix the render material according to the manufacturer’s instructions. Use a mixing bucket and a paddle mixer to achieve a smooth, lump-free consistency. Ensure you mix enough material to cover the entire wall without having to stop and mix more halfway through.
Checking Consistency
The consistency of the render is crucial for a smooth application. It should be thick enough to stay on the trowel but not so thick that it is difficult to spread. Adjust the mix by adding more water or dry material as needed.
Applying the Render
First Coat (Scratch Coat)
Apply the first coat, known as the scratch coat, to the wall using a trowel. Spread the render evenly, starting from the bottom and working your way up. The coat should be around 5-10mm thick. Once applied, use a scratch comb to create horizontal grooves in the render. This helps the second coat adhere better.
Second Coat (Finish Coat)
Once the scratch coat has dried (usually 24 hours), apply the second coat, known as the finish coat. This coat should be around 3-5mm thick. Use a trowel to spread the render evenly, ensuring a smooth, uniform finish. Work in small sections to avoid the render drying before you have smoothed it out.