Over the last few years my research into natural building techniques and materials has seen me investigate various alternative possibilities to the current construction paradigm. From the onset of the hempcrete revolution to the global phenomenon of Earthships; using recycled materials.
Natural construction holds so many positive implications for both the builder, the inhabitant and the greater environment when adopted on a large scale. Straw in particular is a wonderful material to use for building and despite the story of The Three Little Pigs, structures built using straw bales are extremely long lasting! Some of the benefits of using straw include:
- Straw is an agricultural byproduct of crops such as rice, oats, barley and wheat. In this sense, it is renewable, sustainable and non-energy intensive unlike materials such as brick and concrete.
- Reduces Environmental Impact – as a byproduct of large agricultural processes, if unused, straw is left to rot in fields or is burnt. It is mostly collected and hence made into bails which are readily available without any further processing. With lower embodied energy and cost, straw is a perfect solution to be considered in housing crises.
- Energy Efficient – unlike its cement and clay based counterparts, straw is extremely energy efficient, both in terms of the initial production and the subsequent heating and insulation costs for straw constructions. A standard plastered concrete block wall will insulate at R1,5 compared to straw bale walls which insulate at a phenomenal R8 to R9, depending upon their thickness.
- Straw bale builds plastered with a lime finish have much greater levels of breathability meaning temperatures in a straw bale room should reach comfortable levels throughout the year without additional heating or cooling.
- Cost effective – at a mere £2 (approximate) per bale, straw is extremely cheap to build with giving potential savings of thousands for builds when compared with traditional building methods. Over it’s lifetime a straw bale build will see savings both on materials and huge heating savings over the years.
- Health benefits – whilst it is massively important to keep the straw bales dry before the build is finished and plastered, the breathability of the final structure means damp and mould is much less likely to form by reducing trapped moisture. Respiratory and impacts associated with damp are near eliminated.
- Hear this: straw bale structures have greater acoustic and sound proofing properties!
- Contrary to popular belief the Big Bad Wolf would not be able to huff and puff and blow the house in, well not if it is built from straw anyway. Straw structures demonstrate much greater seismic resistance due to greater levels of flexibility and strength. Conventional buildings have lower height to weight ratios and transfer the shock to the roof whilst a straw construction will absorb most of this energy. In areas prone to earthquakes straw bales constructions can reduce not only rebuild costs following such events but the loss of life which often results.
With the above in mind from research in previous years, I was delighted to have the opportunity to not only learn about the straw bale construction method, but also contribute towards building one of the largest straw bale buildings structures globally, here on my own doorstep in London!
The Holy Trinity Church in Tulse Hill, South London embarked on the noble mission of using straw to build a 140 person capacity community hall. I first encountered the project back in 2016 through the crowdfunding campaign they were undergoing at the time.
I was intrigued by the pioneering nature (no pun intended) of the project and hoped to be involved at some point. Two years later and I have found myself putting together compressed walls of straw bales.
A timber frame had been erected at the church, having been built on a foundation of tyres filled with shingles. The design and calculations had been conducted by the church team together with Straw Works, the architectural consultant arm of The School of Natural Building who were leading on the project. The aim for the team of volunteers was then to build the straw walls into the cavities between structural posts and then compress these under the roof plates. In order to benefit from the structural and insulation properties of the straw it is necessary to fit bales as closely around the structure as possible, using a process called notching, reminiscent of woodwork joining. The video below demonstrates this well:
Over a short period of days we managed to bring one of the full sides of the bottom floor of the building right up to the 5th and final 6th layers of bales to be compressed under the roof plate (see the featured image for a completed wall section, minus leveling, trimming and plastering.
The process is a great team building exercise, a test of guile, flexibility and perseverance. I thoroughly enjoyed learning how to work with straw and this project definitely heightened my desire to create a space in London which can be used as an education centre for sustainability and ideas of the future.
I have become very interested in Earthship constructions and the way they incorporate not only natural materials, but also recycled materials, Passivhaus methods and organic form. My friend Teresa, who has participated in several of these builds across the globe and is now building in Uruguay, have set a target of bringing such futuristic yet frugle architecture to London!
The environmental, social and even economic advantages of such methods are not something which should be overlooked. They are no longer just the brunt of childhood stories but are completely feasible and practical solutions to many issues which our modern society faces.
The Earthip movement, led by Michael Reynolds and Earthship Biotecture is bringing light to a new domain of conscious and responsible building.