Dr Ross Savage, Head of R&D at K Rend discusses the long-term benefits of render, how its popularity has increased and how to maintain NHBC Standards
Render is becoming an increasingly popular choice among prospective homeowners.
Previously a favoured product among those contracted to remodel an existing home, render has now become a mainstream finish option for new builds.
Housebuilders, especially those involved in smaller plots, where quality and finish can be paramount, are responding to the demand and choosing render over other more traditional brick finishes to create standout and market appeal.
Rendering the external walls of a house provides a level of quality assurance, not only for the house builder in terms of their finished product but for the homeowners investing in a new home.
Aesthetically it offers immediate curb appeal – good for the initial sell – but the benefits are much longer term.
Rendering external walls actually creates a healthier home, depending on the type of render chosen. Those made from hydraulic lime offer a permeable surface, allowing vapour to pass through the building, rather than a sealed surface, which locks in moisture, creating a more favourable environment for damp. External walls that are breathable will be able to regulate humidity creating a healthier home.
This is because, contrary to opinion, render is weatherproof, not waterproof. It still allows water vapour to permeate through while also protecting the building from the elements by allowing the water to run off. A breathable building is very important; allowing vapour to insulate the walls will control the humidity of building, limiting damp and erosion problems. Using a lime based render will be weatherproof and protect a building without sealing completely.
Lime based render is also a flexible material; it isn’t as rigid as cement. This means that brick laid with lime can microscopically adjust to the changing seasons without cracking the structure or causing instability. Houses change over time; in order to allow brick and stone the room to adjust, a flexible material is needed to avoid cracks. Lime based render is softer material helping homes adapt to the small changes that may happen when they expand and contract against weather conditions.
The creation of a breathable, flexible render of the highest quality, is a result of an investment in the science behind the product but the success of the product isn’t just science alone.
Correct application of the product is crucial in assuring the best performance. Housebuilding teams can often find themselves facing numerous challenges during the building process – and increasingly render is becoming widely recognised as requiring specialist skills. Advice on the correct application of products is readily available to avoid costly mistakes and ensure the quality of the finished project.
The latest 2017 NHBC Standards has also included several new changes to the charter – one of which is on render. This is to support housebuilders in raising and maintaining the standard of housebuilding across the UK.
Unlike cement, which is mixed by tradesmen’s hands, render is packaged in metrically measured bags with a carefully constructed ratio, going some lengths to ensure performance standards are maintained.
The materials are based on scientifically measured combinations of ingredients, and while this significantly reduces the opportunity for error, the application of render still does requires understanding and knowledge of the product to guarantee accuracy of performance. Once applied, a product like K Rend’s Silicone Coloured render will eradicate the need for painting – meaning a new homeowner can rest assured they are moving into a home that is low maintenance. Instead of repainting a house every 3-5 years, rendered walls only needs a gentle wash with water once a year.
Render also provides new homes with a small amount of insulation, which, if paired with an external insulation system can significantly increase the building’s energy efficiency ratings, which is a message that will have resonance with prospective new homeowners.
Choosing render offers both functional and aesthetic benefits for the housebuilder and ultimately the homeowner. It should always be considered early on at the beginning of the design stage, with the amount of exposure, movement and construction requirements considered, and the correct advice sought.