The Straw Bale House, known also as The House of Straw, was the concept, design and accomplishment of Sarah Wigglesworth and her partner Jeremy Till. The idea was to create a modern urban working and living environment discovering solutions to both eco-friendliness and sustainability whilst simultaneously promoting awareness to these factors. But how eco-friendly was the build and the materials used? And now eight years after the completion just how eco-friendly and sustainable is 9 Stock Orchard Street?
Before I can examine the ideas behind the design of this build it is better if you first understand the site and layout itself. Firstly the building has an L shape layout with the longer side running perpendicular to the railway line. It has a mixture of levels and a combination of vernacular and modern architecture.
After entering the site through the willow hurdled front gate you will find, from right to left, the railway line framed by recycled concrete gabions with an inner core of fire-regulated reinforced concrete pillars. The office block that sits facing the railway line rests upon metal coils that assuage the vibrations caused by passing trains, which in turn sit upon the gabions
- Moving away from the office leads you into the living area and the stairwell to a five-story tower lined with books that culminates with a reading space overlooking North London.
- Passing through the living room will find you standing in the bedroom wing, which is where the project derives its name as the walls are insulated with straw bales. The bales do not act as load-bearing walls but are merely used for their insulating properties and rest between a timber-framed structure.
The strawbales were unable to be used in their load-bearing way, as planning permission wasn’t granted, however using them as in-fill is advantageous when designing multi-story and complexly planned structures.
- This is mainly due to their high insulating properties, which are reported to be at least three times greater than the minimum requirement. The house is compiled with a multitude of different materials to suit the different needs of the building. The office wall that faces the railway had a need to be acoustically protected and therefore high in mass.
Sandbags were the chosen option filled with hydraulic sand, lime and cement mix, this was intended to harden leaving a soft mix wall visible after the bags had decayed. The reasoning behind this wall is that it contains low cement content and embodied energy than that of a pure concrete wall, but also casting concrete so close to the railway line was not a practical option.
- As previously mentioned the office sits upon recycled concrete gabions that passed load bearing test but not fire regulatory ones. This was the first use of gabions in the United Kingdom as parts of an urban build.
- A large majority of the building is clothed in a type of blanket this, inspired by a doctor of philosophy at Sheffield University, was designed as an investigation into the relation between the disassembly of a structure and the energy costs of a building throughout its existence. Scot Fletcher become conscious that building designs should understand the life cycles of structure, cladding, services and finishes. The building was intended to be sustainable in design and therefore a comparative of embodied energy versus foreseen life span had to be taken into account. Thus it was deemed that cladding would be a medium term item on the fasade of the building due for replacement, by a cheap possibly more efficient material, after approximately a period of three decades
- The straw bales were chosen as they are abundant in the UK and would have otherwise been burnt or possibly tilled back into the soil.
They are a byproduct of harvested wheat, rice, barley, oats, and rye that form after being put through a baler. Compressed so much that their oxygen content is minimal and consequently making them very fire resistant as the bales ember rather than combust. Costing only one pound fifty per bale they would be cheap to replace if needs be, they have practically no embodied energy themselves but transportation make them so.
- They did not opt for the typical American way of building with straw bales as they use an expanded metal mesh to which the render is applied, instead the bales were rendered straight onto with a hydraulic lime plaster.
Rendering this way allows for the bales to naturally control the humidity; this was as a result tested and verified by students from the Architectural Association. Another innovation came with the timber frame and rendered wall parts of the house as they covered the exterior without the use of mesh. This hadn’t, like the gabions, been accomplished or used before within the UK and was possible by attaching natural Heraklith board to the framework.
- Heraklith is a type of wood wool that is considered by some to be the leading brand; naturally durable, protective against fire, outstanding acoustic properties and generally insulates well to hot and cold making this a good choice I believe.
- The house however is constructed with some highly unfriendly non-green materials too. These include corrugated galvanized steel, corrugated polycarbonate and a predominance of steel frame workings. Galvanized steel is made buy dipping the steel in a hot bath of molten zinc, the zinc is stored at around four hundred and sixty degrees celsius which can’t be said to be green at all. Polycarbonates come in a variety of shapes and sizes whilst finding out information on them is very tricky as they are all made from polycarbonate resin and then it is what each individual manufacturer adds to this resin to make their product unique.
Therefore unless you have the exact way the manufacturer makes their own polycarbonate materials it is certain that every type will contain different embodied energy values. However saying that polycarbonate is recognized as having a high embodied energy value generally, and comes second only to the production of aluminium.
- There are several aspects of the building that contributed to its sustainability; one of which being the glazed southern exposure of the house. The glazing helps by providing light and heating in the winter months and has louvers to keep out the heat during the summer.
Another characteristic of the building that keeps it cool is the meadow located on the roof, this is accomplished by allowing evaporation to takeplace. We know that some of the building has already been made from recycled materials but one other element that was recycled is the office block window frames. These were originally the pitch-pine sleepers found on the site after Till and Wigglesworth made their purchase and were decided as a developmental component during the build. They have passive solar heating and two three-thousand litre water tanks providing water for the garden and toilets.
This is in exception to the one toilet in the house which works by means of composting. The airflow is increased with the charitable high ceilings, whilst the library tower has a grill facing away from the prevailing wind to create negative pressure again contributing to the natural flow. They have skylights in the roof that enhance the natural light within the building, consequently reducing the number of lights needed. Therefore in response to ‘how eco-friendly and sustainable is 9 Stock Orchard Street’, the answer is a great deal more when compared to a typical home.
It has many eco-saving factors about it that have a knock on effect either within the site or further afield but there are also numerous other properties of the build that could have been greener in design. Sarah insisted at an Art and Architecture lecture back in 2001 that the building was never intended to be a completely green building but to act as an exploration into eco-ideas within an urban site.
- Therefore to pass judgment on the two Architects and harvest on everything that could have accomplished a greener outcome could be classed as fastidious. Sarah and Jeremy built this as an experiment and to bring awareness to the possible materials we could use for future builds.
The building having received the amount of publicity it has would surely mean that it has accomplished its charge of drawing awareness to these materials.