The use of straw bales in building has been widespread in Canada and the USA for over a century. It has been increasing in the UK and in Europe over the last two decades.

Straw bale walls

The walls of the Footprint are a combination of straw and glass.

© Alison Platt

Approximately 380 standard straw bales were needed. These were sourced from a farm in Yorkshire.

This might sound like a lot of 'straw miles', given that it is grown nearer to Windermere, but straw for construction needs to be as strong, as straight and as tightly baled as possible. The bales also need to be consistent in size and density, and be dry, with no hint of mould or mildew.

Straw from the east of England grows on even, much flatter land than in the west and this tends to make it more consistent both in texture and strength; in 2005 it grew in drier conditions (as is usual) which also helped consistency.

To build with straw it has to be kept dry; no moisture can penetrate during construction, it’s a disaster if it does.

It must be carefully stored so when the walls were going up a canopy was erected to keep off the rain from above and from the sides. At the end of each day the walls were carefully covered and protected until the roof went on; even then the sides had to be kept dry until they were properly rendered.

The render is lime externally and lime / clay internally, finished with a lime based wash.

The main environmental advantages of building with straw are:

• Sustainability: straw is an annually renewable natural material and approximately four million tonnes are surplus to requirements in the UK alone.

• Biogradability: at the end of the building’s life, the straw will biodegrade naturally, leaving no trace.

• CO₂ emissions: it is estimated that over 50 per cent of all greenhouse gases are produced by the construction industry and its associated transport. By using regional sources, we can contribute to a reduction in emissions through transport. Straw bales don’t need to be fired like bricks and don’t need cement. Additionally, as a resource, straw has absorbed and stored CO₂.

• Insulation properties: with almost three times the insulation value of standard building materials, straw is extremely efficient at reducing the heating demands of a building. This means that the soundproofing is excellent too. Use of straw means there is no need for environmentally damaging insulation materials in the walls.

Additionally there are the following 'approach' advantages:

• Creativity: straw can be used to make either a very standard common style building or it can easily accommodate curves and bends in the walls, and deep alcoves and other features internally that give a building character and charm.

© Barbara Jones

• Financial sustainability: or a fancy way of saying it is cheaper in the short term to build your walls of straw, and cheaper to heat your building in the long term. Especially cost effective on materials alone and if you follow the approach below, cost effective on labour too.

• Opportunities for involvement: a straw bale build gives interested parties such as planners, builders, self-builders, environmental advocates and local volunteers an opportunity to become involved in a very 'participant friendly' building method which can also become a community project. The process is well suited to working with non-specialists, and groups and individuals not normally associated with the construction industry, and previous experience shows that it can be very empowering for those involved.

And no, rendered straw walls are not any more flammable than conventional walls. In fact recent tests are showing that the burn time of straw walls is greater than that of bricks.

Nor are they going to attract vermin. Straw is not a food source for mice, rats or any other small animals, although they really like holes in straw (it is cosy), which is why it is important for the walls to be properly rendered and maintained.

Straw walled buildings are also very durable. There are examples in parts of the US (with a similar climate to the Lake District) of buildings going strong even after 100 years.