Exteriors of buildings can be as varied as the properties owners, each having their own look and feel. One way to personalize the outside of a building is by adding exterior render.
Updating and improving the exterior of your home by adding render can help protect the outer surface of your property by covering cracks and preventing ingress of adverse weather conditions
House Rendering can give your home that WOW factor when visitors or potential buyers arrive, giving a great first impression, not on.y giving it a new lease of life but also adding value to the property.
Using exterior render can be a relatively cheap method of improving your home and protecting the substructure underneath.
There is a lot of choice when it comes to applying the finish and we take a look at the options to help you decide which is the best type of render for your home.
What is Exterior Render?
The first step is to making a good choice is to understand what house render is, and which types are available,
Exterior Render is a wet sand and cement mixture which is applied to the exterior surface of your home by hand with a trowel. Polymer modified render is flexible and breathable for use on buildings with solid walls. Used to cover mismatched brickwork on older properties, and create a sharp finish. Render can be painted or self-coloured.
House rendering is basically a method used to clad or cover the exterior of your home, it is applied to the exterior walls by hand using a trowel and float in the same way gypsum plaster is applied to the interior walls, to give a smooth, crisp finish.
The main benefits of using exterior render are:
To help protect the walls from weathering by preventing water ingress through rain or frost. House render can help cover cracks and old brickwork, this helps to protect walls from damp caused by adverse weather, and some acrylic, insulated renders can also help to make your home more energy-efficient.
To provide a decorative appearance to the house and hide imperfections, House rendering is often used to enhance the aesthetic value of the building. It provides a smooth, even finish which can be applied in any color.
Types of Exterior Render
There are several types of render that are regularly use in the construction industry, each one has characteristics and features that may be beneficial in specific conditions here’s a list of the main types of render
The most common type of render is Cement render. It is mixed with water into a thick slurry and applied in several coats to build up a good, even outer layer.
Cement render is normally mixed and applied on site using between 2-4 coats at 2-3 mm thickness to provide a good even coverage.
Cement render can be rigid and inflexible when compared to modern materials, this can lead to small cracks developing allowing rain and wind to penetrate the surface below.
Freezing conditions can also damage the bond between the rendered layer and the subsurface which means fixing cracks as they appear with regular maintenance is a must.
Cement Render is fairly cheap but requires regular maintenance including painting and patching to keep it looking fresh and in the best condition.
It is considered the most cost-effective rendering type for more modern properties, as materials are inexpensive; only the labor to mix and apply can really add cost to using it.
Lime render is a traditional material for covering exterior walls and was typically used over 50 years ago before Cement render became more widely available.
Lime render is both flexible and breathable, which allows it to be used on properties that have issues with damp walls or tend to move more such as older period style buildings.
Lime render usually requires professionals to mix and apply as is can be difficult to work and achieve a high-quality finish
Because of this, the cost for using lime renders is often higher than using other types, especially cement render.
In some cases, Lime render is the only option such as when working with older, period properties due to matching and local building regulations for listed buildings, or where damp is an issue.
Acrylic render is a more modern material and is often applied as a topcoat to an existing finish, it contains fibers that are flexible and help to prevent cracking under normal house movement.
Applied as a wet, thin coat, Acrylic render is normally pre-mixed (ready to use) and can be supplied in a variety of colors and different grain sizes which produce a different texture when dried.
The grain sizes range from 1.0mm, up to 3.0mm, the larger grain sizes giving a rougher texture than the smaller variants.
For a smooth surface choosing a small gain is best, a grain size of 1.0mm will provide a smooth clean looking surface,
Acrylic render can be mixed into any shade or color. It bonds well to pigments which helps the color last for many years, often longer than other types of colored render, reducing the need for time-consuming maintenance.
It also has very good crack resistance and is a relatively cheap material which makes it a good choice for low cost and low maintenance.
One downside is that the material needs to be applied in dry conditions so plan to have this job done in the summer months when some dry weather is more likely.
Polymer render is a cement-based render that has polymer additives used to give the material a superior bonding ability. This makes it a good choice for use on cement and clay bricks, concrete, polystyrene, plaster, and painted walls.
The Render is extremely adhesive and is often used on surfaces that other types of render may fail to bond to due to poor adhesion.
The polymer additives make the render more flexible which helps the material move with the building surface and avoids cracking.
It is often used on modern homes and can be supplied in a range of colors to suit your preferences.
It has very good weather resisting properties that help to reduce the wear and tear on the outside of your home, harsh sun, rain, wind, and snow are all deflected and will be kept away from the building structure for decades if it is applied properly.
Silicone render is one of the latest developments in protective exterior surfaces and one of the most modern types of render available, some manufacturers offer a self-cleaning feature that uses the silicone surface and natural rainwater to wash away dirt, for really low maintenance.
Supplied ready-to-use, this is a polymer-modified render that produces a smooth decorative finish. Suitable for applying to brick, concrete, traditional plasters, and gypsum substrates.
It is applied in several layers, by hand using a trowel and then finished with a float to produce a smooth, crisp surface.
A base coat layer is typically 4-7mm thick with a final render layer of around 1.5mm thickness.
Silicone render is flexible and breathable which means it can be used on a variety of wall surfaces including external wall insulation systems.
This type of exterior render is considered a premium product, which tends to be more expensive than other rendering materials.
The Benefits of Exterior Render
When considering if you should choose to render your home knowing what the benefits are can help you decide, here we have listed the main reasons for using render:
- Rendering helps to protect and weatherproof your home, adding an additional protective layer to existing brick or blockwork by applying exterior render will help prevent water ingress or weathering damage and Render is often supplied with a warranty of in excess of 25 years for normal wear and tear, giving you peace of mind that your home is protected.
- Rendering can improve the look of your property, freshly rendered properties look clean and give a bold presence in comparison to older, worn or tired buildings. A new coat of render can give your property a real makeover. They are available in hundreds of different colors making any look or style achievable.
- Rendering can match and tie together new extensions with existing parts of a building, another benefit of using external render is that it can be used to synthesize different parts of a building together. Just like painting an entire room, rendering a building can cover the seams easily making the whole property look integrated.
- Modern render doesn’t crack. There are lots of different types of render, most of them use a system or mixture of materials that help prevent cracking, the majority of modern renders use a fiberglass mesh base coat layer, which is flexible allowing it to move with the building. The top layer of render that sits over the base layer is thin and flexible which helps to avoid cracking
- Silicone and Mineral renders are breathable much like lime render; these modern materials allow the sub-surface and building below to breathe. This allows moist air to be removed from the inside of the property, reducing condensation and removing a possible source of damp and rot.
- Render is relatively low maintenance, as there is no need to paint it once applied. Lots of modern render materials are pre-coloured before delivery, the additives used mean they are very stable when exposed to UV light, meaning the color will last for a very long time, some manufacturers quote upto 25 years before the color will start to fade, if at all.
- With a price of around £10/㎡ Modern-day renders provide a cost-effective way to protect or revive the outside of your home. This makes rendering a much cheaper option than choosing to clad your home in other materials.
How much does rendering cost?
The cost of adding a rendered surface to the exterior of your home will depend on several factors and it is best to get several quotes from different suppliers in your area, however, the following costs can be used to provide an estimate.
Applying a cement-based external render on top of a ‘scratch coat’ with a final smooth render topcoat, followed by two coats of masonry paint should cost between £30–£70 per m².
The size and style of the property will have the biggest effect on cost, a 2 story building for example will require scaffolding to reach the upper levels and this adds a significant cost.
Rendering a building of 80m² of would cost between £3,500–£5,500, this would represent rendering a typical 3 bedroom home in the UK.
The table below shows some typical costs to render a property:
|PropertyType||Time||Cost (Including Labor)|
|Rendering a small bungalow||4 to 6 days||£1,500 to £3,500|
|Rendering a 3 bedroom semi-detached houst||5 to 8 days||£3,500 to £5,500|
|Rendering a 4 bedroom detached house||7 to 10 days||£4,500 to £10,00|
A more accurate way to estimate the cost is to calculate the area that you want to render, by measuring the surface and using the table below as a guide you can estimate and compare the cost to render your property in the different types of materials:
|Render Type||Cost/M sq
Do I Need Planning Permission for House Rendering?
Planning permission is not required for exterior rendering, for most properties, this work comes under ‘permitted development’.
Updating the exterior with Render, Cladding, stone, pebble dash, or timber is normally permitted unless the area has a special designation such as:
- National parks
- Conservation area
- Heritage site
- If the building is listed or graded for historical reasons.
Always check your local planning department before you start work of this type on your home.
This article was written by: Richard Quinton – The DIY Help Desk Owner, Engineer & technical specialist.
Richard is one of the key partners in The DIY Help Desk team. He is a qualified Engineer, writer, and publisher, educated to Master’s level. He is a keen advocate of DIY and home improvements.
Richard enjoys helping others to learn new skills and reach their goals and believes that passing his knowledge and experience on through his writing is an effective way to positively impact the lifestyles and well-being of others on a larger scale.