Very few people have asked us “Why do you want to build your house out of straw?”
Maybe that’s because anyone who knows us, would know that we wouldn’t have the good sense to build with good reliable solid concrete. Plus you might ask, “if it’s such a great idea why isn’t everyone doing it?”
We’re building our farmhouse and new farm offices, guest house and cottages out of straw because we love working with straw as a building material. In fact I believe it’s one of the best kept secrets out there. Most of our knowledge of building materials and techniques is fed to us by large DIY chains and building material businesses who wouldn’t dream of marketing such a material as there no mark-up to be made. It was only with the advent of programmes like Grand Designs (Channel 4) that such building techniques were introduced to a wider audience.
For those of you who haven’t seen or visited one, strawbale buildings are beautiful, pleasant, and healthy buildings. There are literally thousands of images of beautiful strawbale buildings on the internet, e.g. facebook.com/strawbuild and http://pinterest.com/preymanta/dreams-of-living-in-a-straw-bale-house/. For those in the UK and Ireland you may also want to purchase Barbara Jones’s “Building with Straw Bales” and for those in the US, I’d recommend “Strawbale Home Plans”.
Here are my 10 reasons for building with straw:
I believe that the dissemination of strawbale building techniques will allow ordinary people to shift the dominant paradigm of home building, which is left in the hands of the “experts” and suppliers, by empowering themselves to build their own homes. Here’s my note of caution.
Having worked as an energy consultant and Building Energy Rating assessor for a number of years I have been summarily impressed and disappointed with examples of natural building techniques and so-called energy efficient homes. What on paper can look amazing in terms of energy performance and carbon savings, is not always realised in practice. You as the home owner are ultimately responsible for the energy performance and the integrity of your own home. So read up and ensure you’re getting the right deal.
Strawbale walls are aesthetically versatile. On our own build, we are opting for an old country farmhouse with a flatter planed walls with the rough finishes both inside and out. However straw bale buildings are often shaped as round houses and/or have undulating walls. The actual bales and clay plaster can also accommodate built-in furniture, niches or sculpted exterior features.
This works in 3 ways:
- As the travel distance for the transport of the key materials is much reduced, less pollution and energy consumption results from sourcing the main building material from the fields
- The use of straw is seen as a method of carbon storage, as the carbon absorbed in the growing process is then trapped inside the walls for hundreds of years. So it’s as good as planting trees
- The internal environmental health and air quality inside the building will be enhanced by the breathability of the materials and the lack of chemicals which can cause health problems when we are forced into contact with them over long sustained periods.
A typical cross-section of a wall with lime render exterior on a clay skin on a bale thick wall with another skin of clay and lime-wash equates to a u-value of around 0.13W/m²·K. The latest Irish Building Regulations 2011 are to achieve a u-value of 0.21W/m²·K which would require the use of insulation and other potentially expensive materials to achieve the same. Unless the materials science moves on in leaps and bounds it will be hard to achieve u-values of 0.13 without recourse to expensive measures.
Also thanks to the “breathable” nature of the wall make-up it is easier to regulate internal temperature of the buildings during hot and cold periods, making a low grade heating system or PassivHaus design more feasible.
I spent a week last October with Bee Rowan of StrawBuild on her course at The Centre for Alternative Technology (www.cat.org.uk) and I came away feeling good and empowered to build my own strawbale buildings. As it’s a low tech building technique, a motivated individual could start building having completed a short course.
I’m watching the green shoots of barley straw pushing up through the dry Meath clay loam on our farm and thinking “That’s my house growing in those stalks”. When you look at it like that, how could you not build with straw? The clay for the plaster is another local material and we could even quarry and slake the lime, as would have been done a hundred years ago in our beautiful lime kiln in the farmyard. But I think we’ll leave that for another time!
Cost effective material
Which is probably why it’s not widely favoured in the building industry as it is supplied as a raw material and therefore doesn’t have much potential for mark-up.
Load bearing strawbale buildings also reduce the amount of materials required as it reduces the amount wood required by a timber frame structure with infill walls and the plastered bale wall replaces the insulation, the drywall and the paint usually used on a conventional wall.
Good fire resistance
Strawbale walls have a very good fire rating: 1 hour for clay plastered walls, 2 hours for lime rendered walls. Whereas a typical timber frame dry-walled structure would have a 30 minute rating.
Internal sound quality
Strawbale walls provide excellent sound insulation and have a positive effect on interior acoustics.
It’s fun working with straw
Strawbale building projects draw friends, neighbours or enthusiastic volunteers and course participants who want to contribute to a positive story. It’s important to keep the energy positive, as at the end of the day you’re building someone’s home or work place and the more positive the energy that goes into making that building the happier the occupants will be. That may sound touchy feely, but it’s an important point for any building project, and it means that even Caspar our youngest is keen to get involved.
Caspar mid bale with author and Bee Rowan of Strawbuild.org.uk