Strong colours, silicone technology, textured effects and brick slip combinations – James Ormerod of Aliva UK sets out the ‘art of the possible’ with insulated render
When looking for a cost-effective cladding option that can be applied quickly and easily, architects can often opt for external wall insulation (EWI). But, rather than being considered a cladding ‘common denominator,’ reliable insulated render systems can create colourful, stylish exteriors that stand the test of time and stand up to the elements.
Contemporary tones, bold colours, bespoke pantone colour matches and self-cleaning technology mean EWI is enjoying a new coming of age. Used as a standalone finish or in combination with brick slip ranges, the choices available today show just how sleek, vibrant and contemporary insulated render can be. That’s alongside exemplary thermal credentials that complement buildings across a swathe of sectors from retail, residential, hospitality, education through to leisure.
Energy-conscious
Given that more than a third of the heat in any building is lost through its walls, high-quality insulated render can deliver a crisp, contemporary finish for any energy-conscious building project.
EWI meets modern thermal requirements, while providing beautiful, weatherproof and long-lasting finishes for external walls. Whether it is being used on a new build or a refurbishment, there will be a render type and colour to fit the project. From gentle hues or pastel shades through to vibrant accent colours and bespoke colour matches, the right, UV-stable compositions are possible with today’s EWI systems.
Equally important in the current landscape, EWI systems with Euro Class A and B fire performance that complies with current Building Regulations as well as insurance standards, alongside BBA certification and using suppliers with INCA membership.
Design textures
Today’s EWI systems can be used to mimic a range of ‘texture’ designs, decorative surfaces and textured coatings with high aesthetic value for contemporary, unique and entirely customised projects.
Texture aesthetics available include: corten, washed cement, brushed concrete, urban and wood effect, Travertine, streaked, crushed, matt sandblasted and glitter sandblasted effects. Texture design finishes that can be applied to substrates include cement-based plaster, painted plaster, lime-based plaster and paint, exposed reinforced concrete, precast concrete features and panels, gypsum and fibre cement walls and features, after previous treatment where necessary.
Self-cleaning technology
An example of the self-cleaning abilities of insulated render, the 193-bed Holiday Inn Express hotel at Aberdeen Airport specified a silicone option that would not only look stunning but be highly durable. Architects White Ink and the client wanted the building to retain its fresh, sharp and attractive aesthetic. Aberdeen experiences extreme weather conditions, and the hotel is very exposed to the elements. It is also in close proximity to the airport, with all the associated pollution, so the ability to self-clean was an important design requirement.
The silicone allows rainwater to bead on the surface and then run down, taking dirt and grime that would otherwise attach itself to the damp face of the building, with it. The silicone insulated render was also awarded certification from the Fraunhofer Institut fur Bauphysik in Germany for algae and fungus-resistant coatings.
Bold in black
To deliver a cost-effective, visually striking and energy-efficient facade for a 245-bed, four-storey hotel at Gatwick Airport’s south terminal, architects Scott Brownrigg specified insulated render in a bold black.
A mineral wool insulated render system created a first-class thermal fabric for the walls of the hotel. While the surface was still wet, a tailored alkali-resistant, woven glass fibre mesh was bedded in, before being coated with another layer of mortar and finished off with a trowel-applied continuous layer of silicate coating and a black acrylic top coat for a luxurious look.
As a result of the render’s specification, heat does not escape from the walls in winter, and solar gain is minimised in the summer, creating a comfortable environment for hotel guests. The cold pigment finish allows darker colours to reflect heat rather than absorb it.
EWI replicating rainscreen cladding
A desire to achieve a striking rainscreen cladding ‘look’ on a reduced budget at Fabrick House in Cheadle saw a novel EWI approach deployed. The dilapidated 1960s office block, undergoing a conversion into a modern apartment building, saw an insulated render system installed but with textured finishes to replicate a rainscreen cladding aesthetic.
Clean blue and white tones and a dark banding effect achieved the desired visual impact, while simultaneously meeting current U-values for the external walls. Opting for an EWI system rather than a bespoke rainscreen panel system reduced the programme timeline, while also mitigating any risk around external cavities; including potential for moisture ingress over the longer term.
The proximity of the West Coast mainline, only 20 metres from the building, meant high acoustic values would be key to comfortable living and these were achieved alongside all standard regulatory requirements. The system achieves A2-s1 d0 fire rating and therefore complies with Building Regulations for buildings over 18 metres in height.
EWI/brick slip combinations
Architects can ‘dream big and dream bold’ with EWI and brick slip solutions, which offer versatility, adaptability and cost effectiveness where insulated render is combined with clay, lightweight, stone and ceramic slips for example.
EWI can be combined with a range of brick slip solutions to realise bespoke brick slip design with scale and scope rather than watering down architectural aspiration due to cost parameters. Facade specialists well versed in Modern Methods of Construction can advise on weight and support systems, through to the cost efficiency that EWI and brick slip solutions can offer.
A combination of EWI and clay slips were deployed at St Vincent’s, a modern, six-storey student accommodation block in Sheffield. The design by HCD Architects required a system that had to be flexible enough to accommodate a stepped feature to the masonry facade. A solution using EWI and two thicknesses of clay slips – 15 mm and 25 mm – created a stepped detail in line with the architect’s design intent.
Delivery of the works had to take into account the proximity of neighbouring 19th Century, Grade-II Listed St Vincent’s Church which has been fully refurbished as a communal student facility within the overall site development.
The project was highly commended in the Architectural Design category at the 2019 Insulated Render and Cladding Association Awards. The judges were particularly impressed because they felt that it set a good example for the future of EWI. They also recognised the challenges that can occur when working so closely to a listed building.
James Ormerod is managing director at Aliva UK