Liverpool Plasterers

Rendering

We offer plastering services to residential, commercial, and industrial customers in the Liverpool.
Rendering is the process of applying a rendering material to an exterior or interior surface. The rendering will add durability and protection from moisture, and provide a smooth finish for plastering. This guide will answer many questions about rendering, including why it’s so important, how rendering works, what different types of rendering there are, and how much does rendering cost on average? And more!

The importance of rendering

Rendering is a process that will provide protection from moisture, and add durability to your external or internal surface. It also provides a smooth finish for plastering on top of it. The rendering material used may be lime-based, cementitious (lime+sand) based, gypsum-based, or petrolatum paint additive rendering systems, which all have different properties such as water repellence, airtightness, and absorption of sound energy. When you think about the exterior walls in some older buildings, they often crumble away because they were not properly rendered when originally built!

Another importance of rendering is in rendering the plaster. Yes, rendering is actually a two-stage process, and in order to have an attractive finish on your exterior walls, it’s important that you render all over the outside walls as well as inside them too!

The rendering we use at our company always includes specialist sealants that will protect from moisture, and add durability to your external or internal surface. It also provides a smooth finish for plastering on top of it. The rendering material used may be lime-based, cementitious (lime+sand) based, gypsum-based, or petrolatum paint additive rendering systems, which all have different properties such as water repellence, airtightness, and absorption of sound energy when it comes time to plaster.

Our procedure for rendering

We can render many types of surfaces with a variety of materials, though most people describe rendering as applying an additional layer of rendering on top of a surface such as brickwork, concrete, or plaster.
There are many types of rendering materials and we use different materials depending on the desired effect. Some renderings have more water repellent properties than others, so it is important to think about what you want your rendering to do before choosing which type to apply!

The first step we take is to remove any loose rendering which is contributing to the cracking, and then we go about applying replacement rendering. We use a render mask to control where rendering goes on the surface so that it doesn’t get applied over areas you don’t want rendering, like windows or door frames.

We apply our material with an earthenware paintbrush in two coats (one coat for thicker materials).

After that, we leave the rendering to dry for at least two weeks before plastering.

Types of rendering

The most popular rendering systems today in domestic buildings are cementitious-based renders, which can be applied by either trowel or roller coating onto surfaces such as masonry walls, rendered blockwork (also called reinforced concrete) blocks, and other substrate materials such as wood panels. These products may contain additives that improve their performance characteristics — for example, fire retardants; air-entraining agents to produce a denser rendering material with improved resistance to shrinkage and cracking; or corrosion inhibitors, which reduce the incidence of efflorescence.

Acrylic render application

In this process, a rendering is applied over a substrate employing an acrylic emulsion or other water-based product.

Oil render application

The materials are usually pigmented oil paints, though latex paint may be used in some cases. These products are typically applied with a brush or roller to the surface and then covered up with a plasterboard for protection before they dry too hard.

Water-repellant rendering systems

There are many rendering products available that have been designed specifically to resist the effects of damp conditions such as efflorescence (the deposition of soluble salts on surfaces) and rising dampness (when moisture rises through porous masonry walls). A hydrophobic rendering places a coating that repels water molecules and slows water seepage. This can be achieved either by using inherently hydrophobic rendering products or by using a rendering system containing an acrylic co-polymer additive which becomes water repellent when it is applied to porous surfaces and exposed to the air.

Traditional lime

Traditional lime rendering has been improved by rendering manufacturers to be more waterproof. Rendering that has passed the British Board of Agreement (BBA) standard is known as BBA Hydrophobic Lime.

K-rendering

K-rendering is rendering that has passed the BBA standard and is certified to be 100% waterproof. Rendering manufacturers also offer a wide variety of other rendering systems to cope with different surfaces.

Polymer rendering

Polymer rendering is rendering that has passed the BBA standard and is certified to be 100% waterproof. Rendering manufacturers also offer a wide variety of other rendering systems to cope with different surfaces.

Lime rendering

In lime rendering, the rendering surface is a mixture of lime and water, the mix is known as “lime putty”. In much the same way, your house’s walls must be rendered to protect the building from damage caused by moisture or other factors. The rendering process includes plastering with thin layers of mortar/concrete onto dry stone blocks until they meet an agreed standard thickness before applying to render on top (or in some cases, rendering will first be applied directly to concrete). Lime rendering can also be used for dampening existing surfaces where they are not structurally sound enough for traditional rendering techniques such as polymer rendering. This technique has been adopted throughout Europe, especially in areas experiencing high levels of rainfall. It is important, though.

Cement rendering

Cement rendering is much different because it involves rendering on top of a concrete surface. Lime rendering is also used for dampening existing surfaces where they are not structurally sound enough for traditional rendering techniques such as polymer rendering. This technique has been adopted throughout Europe, especially in areas experiencing high levels of rainfall.

Spray rendering

In spray rendering, we use a rendering gun to spray the rendered material onto a surface. It is important, though, that we use this technique on stable surfaces such as brickwork or block, and not concrete because it cannot adequately hold the weight of rendering materials.

Lime rendering

Lime rendering is much different because it involves rendering on top of a concrete surface. Cement rendering is also used for dampening existing surfaces where they are not structurally sound enough for traditional rendering techniques such as polymer rendering. This technique has been adopted throughout Europe, especially in areas experiencing high levels of rainfall.

Tools we use for rendering and their uses

There are various tools we use for different types of rendering. However, the basic ones and their uses are as follows:

-Trowel for rendering onto a surface

-Brush for rendering on or between joints in brickwork

-Roller for rendering large areas of surfaces.

Other tools include a rendering knife, a rendering board, and an edger.

Plastic Render Float: this tool is used to create even layers when applying plastic renders over concrete foundations/rubble bases, e.g., LVF (lightweight expanded polystyrene). The design features two angled handles that enable the user to ‘float’ the material evenly without leaving any lines or marks where it has been applied before drying, hence its name; is also sometimes called “floaters”. It is used as a squeegee for rendering.

-Rendering Board-Used when rendering brickwork joints

-Edger-Use it around windows, doors, etc. as well as finalizing any edges that may have been created during rendering with other tools.

-Spade-Used for rendering on uneven surfaces or rendering from the top of a wall down

Speedskim. This tool is for rendering uneven surfaces.

-Corner Brush-Used for rendering around corners

-Filler pad (or “squeegee”)-Use this to apply rendering in place of a trowel, or as a more effective wet/dry method of rendering with the corner brush

-Damp sponge-For applying rendering where it has been applied with tools such as speed skim and corner brushes before drying; also ensures that there are no bubbles left in the render when dry by smoothing out any air pockets which may have formed beneath it during application.

Frequently Asked Questions

The average cost of rendering

Costs depend on factors, including what type you intend to use and how much area needs to be covered, but typically, professional rendering starts at around £20 per hour. However, actual prices will vary, so always check first with your chosen company. The costs may also depend on what kind of rendering you are using. For example, if your rendering needs to be a certain color, that can incur additional costs.

How long do I wait for the render to dry before plastering?

The drying time will depend on factors like temperature and ventilation in the room, but it is usually about 24 hours after application until it has dried sufficiently. However, this can also vary depending on other circumstances, so always check first with your chosen company. There may also be other factors involved, such as particularly humid weather, which could prolong drying times further still.

Are there hazards in rendering?

A risk when rendering includes inhaling too much dust from sand or cement particles while they’re mixing, but these risks are greatly minimized by using a respirator.

Another hazard is the use of acids in rendering, but this is also greatly minimized by using gloves and eye protection.