The Benefits of Rendering a House

Rendering a house can be a great way to spruce up its appearance, while also offering resistance to water penetration and allowing a house to be externally insulated. In this guide from Building Materials Nationwide, we’ll explore how render is produced, the benefits of rendering a house, and the types of render used within the UK.

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What is Rendering?

Rendering is the use of a special mortar mix, known as render, to create smooth exterior walls on a building. Mortar is made from a combination of cement, water, and fine aggregates, sometimes with the addition of lime. Different ratios and additives allow mortar to be used for holding bricks and blocks together within a masonry wall, interior plastering, and exterior rendering. While rendering and plastering produce a comparable result, the mix will be different, with render designed to be more rugged in order to withstand the external weather.

Why Render a House?

There are a few different reasons that people may look to have their house rendered, from creating an attractive look for their home to installing insulation. 

• Rendering For Visual Benefits: Rendering will replace the brick or block look of a wall with a smooth and consistent surface. This can offer improvements to concrete blocks, which are seen as unattractive by many, and for traditional bricks in cases where varying colours of brick have been used, or where the bricks are starting to look worn. While traditionally white, render can be dyed or painted in a range of colours. If looking to paint a rendered wall, masonry paint will normally be used. It can also be covered with options like brick slips, which are thin facings designed to replicate the traditional brick look.
• Rendering For Penetrating Damp: Exposed brickwork can be the cause of penetrating dampness within a house or other masonry buildings. This can be due to the type of brick used, damage to bricks, or high levels of wind-driven rain. Penetrating dampness can cause a wide range of issues within a property that can be costly and time-consuming to fix. Applying a solid layer of render to the exterior of your home can be a great defence against penetrating damp, though you should have the walls assessed before opting for it to ensure they are suitable.
• Rendering For External Wall Insulation: Installing insulation to the walls of a property is a fantastic way to preserve heat and reduce energy bills. While most modern homes have cavity walls, which can be insulated with blown-in cavity insulation, in older houses with solid walls you’ll need to opt for either internal or external wall insulation. External wall insulation will involve attaching specialist insulation boards to the outer walls, which will be covered in mesh and rendered for a smooth finish. If a cavity wall is damaged or in an area with high wind-driven rain, such as Wales, it may be unsuitable for blown-in insulation and external wall insulation can be used as an alternative.

What Types of Render Are Available?

When looking to render a building, alongside traditional cement render systems there will be a selection of other options available, which can have specific visual or structural benefits, and some clear pros and cons.

Cement Render

This will be the standard option for rendering a building such as a house. Sand and cement will be mixed together with water to create the render finish. This will be naturally grey, and can either be painted over once dried, or dyed during the mixing process to create a coloured render. This is a cost-effective measure that has some issues such as cracking over time and needing to be repainted. It also prevents water evaporation, which can cause huge issues if the render cracks and water gets behind it.

Lime Rendering

While it makes the mix more expensive, adding hydrated lime to a cement render can bring a range of benefits to usability and performance. Lime render will be easier to apply with a trowel, and will be less likely to crack once dried. It will also better allow moisture to dissipate, and reduce the risk of damage from frost. In general, this contributes to superior durability.

Pebbledash Rendering

This is a type of rendering used traditionally on UK homes that involves throwing aggregates at a freshly rendered surface to create an uneven texture that can be left as-is or painted over. While this look was hugely popular when first used, it has lowered in popularity over the years and is rarely used now. In fact, many homeowners opt to have their pebbledash render re-rendered with a more modern clean look.

Acrylic Render

Acrylic render will have acrylic resins added during mixing. This will bring structural benefits by reducing the chances of cracking. Acrylic renders can also come in a range of colours, though it’s worth noting that they lack breathability. These are sometimes referred to as polymer renders.

Silicone Render

This will be a cement-based render with silicone added. This will offer similar benefits to acrylic render except without the sacrifices to breathability. Silicone render is an expensive solution however, which is something to consider when looking at your best options. It can also only be installed during the summer, as it requires higher temperatures to adequately dry.

Cork Render

This is a more recent innovation, involving cork for a textured finish. Cork render possesses thermal and acoustic insulation properties, alongside the flexibility to avoid cracking, and water resistance. It is also an environmentally friendly option, as cork is removed from trees that will naturally grow more, meaning that they do not need to be harvested. Cork render can be installed with a range of coloured finishes.

Rendering Different Building Types

The best rendering option will depend on the material the building is made from, as well as the look of any surrounding buildings. Brick or block homes can be rendered over with a wide range of options but homes with timber cladding should avoid options that are not breathable, as this could contribute to mould growth. If looking to render an existing home, an expert assessment of the outer walls should be carried out before you begin work.

When you are in a terraced or semi-detached house it is also worth considering how render will work with your neighbouring houses. If for instance, you are looking to install external insulation, the size of your house will be increased due to the insulation boards. If you render a house bordered by brick homes it can stand out. In some cases, planning permission may be required to render a house, and in listed properties or conservation areas you may be restricted when it comes to rendering and the colours you can use.

What is the Ideal Cement Mix For Rendering?

A lime cement render would be made from 6 parts rendering or plastering sand, 1 part cement, and 1 part lime. Using sand that is designed for rendering is essential, as others could be too thick or coarse to give the smooth appearance required.

How is Wall Rendering Applied?

Firstly, all paint and existing render will be removed if possible, before the wall is cleaned with water. The render will be applied with a trowel in two separate coats, the first of which will be marked with a scratch comb to help the second adhere. Each coat will need to be measured and carefully flattened, to give an even and smooth appearance.

Rendering is an expert task, that can look and perform poorly when applied incorrectly. It will also normally require several workers at once to ensure that the full wall is coated and flattened before parts of it dry. It is also likely to require scaffolding to install. Adding external insulation to a house is also a complex professional process, with building regulations governing how it must be installed.

The Cost of House Rendering

While it can bring several benefits as mentioned, opting to render a house is an investment that comes with a large price tag. According to householdquotes.co.uk, rendering a 3-bed semi-detached house will cost between £3800 and £5500, which could be prohibitively expensive for some homeowners. Traditional cement render will cost about £10 for materials per m2, compared to £20 for lime cement, and £30 for acrylic and silicone.

High-Quality Rendering Supplies Delivered Across the UK

Building Materials Nationwide works with professionals across the UK, delivering quality building materials to them. Through our website, you’ll find a range of renders and accessories for sale, alongside our selection of aggregates and cement. We aim to offer everything a builder could need in one place, delivered to them at a great price. For further benefits, those in the industry can sign up for one of our trade accounts. Our trade accounts give access to the services of a dedicated account manager, who’ll be able to organise orders including sourcing specific products from our network of suppliers. We also offer competitive trade pricing and express delivery across the UK.

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