What are the types of render & how can systems protect your home against the increasingly harsh and adverse UK weather.
In this post, we will look at what are the types of render available and how they compare. The range of finishes, weathering performance, and colours available make rendering a property both a technical and aesthetically pleasing option for homeowners, who are looking to make essential repairs, or who simply want to make their property stand out from the crowd, add value to their home and protect against the weather.
Typical British weather conditions can be very unforgiving, more so now than ever. Our homes are increasingly under attack from adverse weather, such as higher and longer periods of wind-driven rain, year-round extended periods of frost, sleet, snow, storm fronts, and heat waves. These weather changes, coupled with typical age-related building fabric wear and tear, inevitably lead to many homes suffering from issues such as dampness. When this occurs, homeowners generally look at ways to improve their property’s weather resistance by keeping the elements out whilst improving its appearance, both of which add short and long-term value to their properties. In recent years, there has been a growing trend in the new-build and refurbishment sector for modern render finishes – with bright, shiny, new exteriors popping up all over the UK.
The rendering process consists of overcoating the buildings existing masonry exterior walls. The application of the render can prolong the life of a building by adding a weatherproof barrier between the brick construction and the elements. It is also a great way of refreshing tired, damaged, or mixed brickwork with a consistent overall finish across a property.
There are three commonly applied systems to choose from. These are cement & sand, monocouche, and thin coat renders; which one you choose for your project depends on what characteristics and performance you require from the final product.
Sand and Cement (Traditional) Render
Sand & cement render is a traditional render finish that is mixed on-site and applied in multiple coats. The sand and cement, once applied, must then be left to cure for a period of weeks before being overcoated with masonry paint. This system is generally slightly cheaper from a materials point of view. However, it can be more susceptible to fail/crack, as it is not very flexible, and its performance is heavily reliant on the correct mixing of the materials, as it is not pre-mixed off-site in a modern, quality-controlled factory environment.
Ecorend manufacture a pre-mixed OCR (Ordinary Cement Render) render to meet the needs of this market segment, which is designed to help eliminate inconsistencies associated with site-mixed product.
Sand and cement render pros:
Can be more cost-effective in materials.
Sand and cement render cons:
Not flexible, has lower breathability, is harder to apply, and requires overpainting.
Suitable for masonry substrates only.
The system’s durability is heavily reliant on the skill set of the applicator mixing the product correctly. Incorrect mix strengths and poor mixing practices can often lead to the deterioration of an existing building’s fabric, which must be considered when specifying the sand, cement, and lime mix ratios.
What does it cost:
The cost of sand and cement render can vary but generally, as a guide, it’s in the price range of £25 – £45 per m2 (including labour and materials), depending on the location and size of the project.
Monocouche Render
Monocouche render is mostly specified as a single-product, two-pass system, with A1 Fire classification, high adhesion, weather resistance, and breathability, all within a through-coloured decorative render, commonly known as scratch render, although other finishes can be applied (see below), which is suitable for external use across most types of traditional masonry brick, blockwork, or concrete.
The application of monocouche renders can be done by either hand or machine. Monocouche render is available in a variety of pastel colours and can be finished in a number of ways such as scratch, roughcast, ashlar and float.
Ecorend monocouche range has 32 colours to choose from, whilst options remain for bespoke colours for larger commercial developments. Monocouche render is a very popular choice for homeowners who are looking for a crisp, textured flat finish, with smooth, clean edges and detailing.
The system is quick to apply thanks to the one ‘one-coat, two-pass system’, which becomes even quicker when machine application is adopted. Depending on the substrate; sealants and base coats may be required to ensure the system performs as designed.
For scratch finishes, it’s simply a case of applying the monocouche, allowing it to set until it is ready to scratch back to achieve the desired stone effect. There is no need to apply additional paint, as this system is a through-coloured render, meaning the colour pigments run through the thickness of the render.
Monocouche render is long-lasting, with a minimum 25yr life expectancy. As with all building fabric, the render will reach its tested life expectancy with regular care and maintenance (See Ecorend MR1 BBA Certificate for further information).
Ecorend manufactures a range of coatings and sealants designed to help maintain and maximise the lifespan of your project, supported by a range of technical papers, that provide guidance on the maintenance of their renders.
Monocouche render pros:
Monocouche renders are water repellent with excellent weather-proof properties for the duration of their life span and hold A1 Fire classification.
Monocouche render comes in a variety of colours and finishes; enabling customers to create the perfect look for their home, that meets their individuality and style.
Monocouche renders are more commonly adopted by house builders and homeowners looking for fast application, weatherproofing properties, fire resistance, and an attractive finish for their project.
Monocouche render cons:
Colour options are more limited when compared to silicone and acrylic renders.
Monocouche is not as flexible as silicone or acrylic renders.
What does it cost:
The cost of monocouche render can vary depending on what substrate it is being applied onto, as a base coat and/or primer may be required. Generally, as a guide, it varies in the range of £45 – £95 per m2 (including labour and materials), depending on location, project size, and the carrying substrate.
Thin Coat Render (Silicone and acrylic renders)
Silicone and acrylic renders are usually called ‘thin coat renders’ because they’re applied in a very thin layer on top of a reinforced base coat. Thin coat render has the advantage of being very flexible whilst providing unrivalled weather resistance. Silicone and acrylic render systems are considered more premium and are generally more expensive as a render solution when compared to other render options. Thin coat systems are more commonly adopted for commercial projects, where a premium, long-lasting, durable product is required. Thin coat renders provide a minimum 25yr+ life expectancy. As with all building fabric, the render will reach its tested life expectancy with regular care and maintenance (See Ecorend Sil-flex, SR15 & 365 BBA Certificates for further guidance).
Ecorend manufactures a range of coatings and sealants designed to help maintain the life of your project, supported by a range of technical papers that provide guidance on the maintenance of their renders.
Acrylic vs Silicone
Acrylic renders use modified polymer structures to ensure that the finish is highly water repellent and flexible, providing very good crack resistance properties. Acrylic renders are not suitable for buildings that require high levels of breathability, or external wall insulation (EWI) systems that use mineral wool as the insulant.
Silicone renders use highly modified polymer structures, that ensure the finish is highly water repellent, highly vapour permeable (breathable), and extremely flexible, giving the very best resistance to cracking. Silicone renders can be applied where breathability is important, and they are suitable for use across all EWI systems, approved render carrier boards, and masonry substrates. Silicone render is considered the gold standard when it comes to external render systems.
Thin coat render pros:
Thin coat render is a ready mixed, wet render that provides a consistent product that is ready to go straight out of the pack.
Thin coat render is very flexible, providing good crack resistance and durability and has a vast range of colour choices.
Having the render pre-coloured means that it can last longer, and eliminates the requirement for painting, drastically reducing maintenance costs.
Silicone thin coat renders provide additional breathability if required.
Thin coat render cons:
Thin coat systems take longer to apply – due to their multi-layer application as they require basecoat, primer, and topcoat applications.
Thin coat renders are slightly more susceptible to weather damage during application and applicators should consider weather conditions, when planning for projects.
What does it cost:
As a guide, a silicone and acrylic render is the most expensive of the three systems – coming in somewhere in the range of £65 – £100 per m2 including labour and materials. Again, prices are a guideline and regional variations apply.
Which system should you choose?
When it comes to What are the types of render & how can systems protect your home against the increasingly harsh and adverse UK weather. the options outlined here will all provide good levels of protection. Having explored the different types of rendering options, it may seem difficult to make a choice as to which is the right choice for your project. Though each system has its advantages, it largely comes down to a personal choice and the budget of the project. Both monocouche and thin coat renders offer an attractive, durable, weather-resistant, long-lasting finish.
Any render system selection must consider the project brief, scope, budget, timeline, and willingness to maintain the finish for the duration of its life.
Though thin-coat silicone render systems are the most expensive of the render systems, they are technically the best systems in the market; however, if you are looking for a more budget-friendly investment that offers outstanding quality, monocouche renders may be the choice for your new build or refurbishment.
Both provide peace of mind with factory-produced consistency, quality-assured, and independently tested product that delivers a more premium feel and finish than sand and cement renders.
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