Create memorable designs through non-standard construction – Wilkinson’s approach to materials
2nd August 2023
Embrace Unusual Materials: Paving the Way for Extraordinary Architecture
As Building Inspectors, we love to collaborate closely with architects and designers, and we are continually inspired by those who fearlessly embrace unconventional materials to achieve not only stunning designs but also performance-driven structures. At Wilkinson’s, we thrive on these challenges and revel in working on exciting projects that challenge the norms of commonly used building materials.
The importance of a building’s structure and performance cannot be overstated, and when combined with unconventional and innovative materials, the result can be nothing short of extraordinary. Nevertheless, these ventures require specialist support and advice, especially considering that they deviate significantly from the familiar brick-and-mortar houses we commonly encounter.
Here at Wilkinson’s, we boast extensive experience in working with a range of non-standard materials, including ICF, CLT, green roofs, and even straw bale buildings. Speaking of which, we are working on a straw building at the moment with the Montessori School in Uckfield. Let’s delve deeper into the remarkable qualities of straw as a construction material.
Straw as a building material
Despite conjuring up images of children’s fables involving wolves and little pigs, Straw is one of the oldest and most traditional building materials known to humanity, having been utilized in construction for thousands of years. Historically dating back to the Bronze Age, straw-thatched roofs were a prominent feature of rural British constructions, owing to the abundant availability of this material. Straw roofs possess a shaggy and picturesque appearance, and typically require replacement every 10-15 years, though some have impressively endured for nearly half a century.
The first known use of straw bales for construction dates back to a Nebraska schoolhouse built in the mid-1890s. While it enjoyed popularity for a while, newer, more modern building materials eventually overshadowed its use, causing it to fade from prominence.
However, despite its temporary decline, building with straw bale boasts numerous advantages that should not be overlooked. For starters, straw is a renewable energy source and lightweight, making it an excellent insulator. Adopting straw and other plant-based materials in construction significantly reduces both embodied and operational carbon when compared to conventional methods. Furthermore, using high-quality bio-based materials, such as straw, clay, and lime plaster, ensures that the indoor air quality in straw bale buildings contains minimal or even zero volatile organic compounds, creating a much healthier living environment.
In response to the pressing climate agenda, interest in straw bale construction has witnessed a resurgence, with the European Strawbale Building Association (ESBA) estimating that the number of buildings constructed with straw every year in Europe will skyrocket to 50,000 per year by 2030, up from the current level of around 1000.
Technical issues: With growing interest in the use of straw bale let’s look at the main concerns that building inspectors naturally raise – e.g. concerns regarding structure, fire safety, dampness, and mould issues.
Structure: Straw bale construction is best suited for low-rise buildings but can be combined with other materials, typically timber frames, to enhance its load-bearing properties.
Fire: Extensive testing has dispelled old perceptions of the fire risk associated with compressed straw bales. The density of strawbale construction provides a near airless environment, allowing for fire ratings that comply with building regulations. Additionally, applying clay and lime plasters effectively seals the bales, further increasing fire resistance. Designers can confidently specify clay and lime plastered strawbale wall systems, achieving impressive ratings of B-s1,d0.
Dampness and Mould: Research on mould growth in straw buildings has been limited. However, strawbale buildings consist of breathable materials with properties that regulate relative humidity, thus mitigating mould growth. Additionally, alkaline lime plaster reduces the risk of mould. Quality control during the storage of bales is crucial to ensure that affected ones are not used in the straw bale building.
How We Bridge the Gap:
Working with alternative building materials inevitably presents both benefits and limitations. At Wilkinson, we excel at bridging the gap between creating something unique while ensuring structural integrity and sustainability.
Achieving architectural brilliance with less conventional materials like straw bale is entirely feasible with the right support and expertise at hand. We will guide you throughout the process, ensuring your project excels in safety, design, and quality.
If your project is still in the design phase, now is the perfect time to reach out to us. Our materials-first approach will ignite creativity, and we will provide expert guidance on building safety and compliance when incorporating unusual materials. The result will be a stunning piece of architecture that we can all take pride in.
Ready to make your project stand out? Get in touch with us today. Together, we’ll craft a masterpiece that defies convention and embraces the extraordinary.
Sarah and Jeremy beneath the Grand Designs Straw Bale house. Photo: Jefferson Smith
The Straw Bale house in North London, featured on Grand Designs in 2003 is a prime example of the switch to a less common building material in order to achieve an architectural design. It shows what we can truly achieve when we put building materials first.
Architects behind the design, Sarah Wigglesworth and Jeremy Till, were asked:
Your walls are made from straw bales. How are they working?
The straw bale walls have been great. Various people have tested them, and found their humidity is similar to that of timber, which means we won’t get mould growing inside the house. They’re energy efficient and very cost effective to build with.
Are there any technologies or materials around now that you wish had been available for your project?
Photovoltaic panels, which convert sunlight into electricity, are improving all the time, and crop-based materials such as Hempcrete – made from hemp and lime – are now easy to get, so I’d love to use those in a future design.
As an architect, what’s the most common mistake you see clients make?
People are always in a rush to complete their projects, but it’s really important to take the time early on to work out what you want and to try out different options. Also, you have to be able to communicate with your architect. A lot of people don’t understand the architect’s drawings, which is where problems can arise.
Building Regulations are seen as a set of rules to be followed, which, yes, essentially, that is exactly what they are, but building regulations don’t need to constrict architects.
The Building Safety Act 2022 received Royal Assent on 28 April 2022, marking a monumental shift in the regulatory landscape for building safety in the UK.