Strawbale Building

It is important to note at the outset that straw is not the same thing as hay – this is a common misconception for town folk, lol.  Hay contains grass seeds and will attract all kinds of critters looking for a ready food supply.  Straw, properly harvested and baled, contains minimal seed and can be sourced as a by-product, often a waste product, from many grain crops for example rice, barely, wheat etc...  Straw is an ideal medium for building bale walls in most climates (except the tropics and sub-tropics), hay is ideal for feeding to hungry animals. 

Another common misconception, perpetuated by the three pigs story (brick sales propaganda in disguise), is that a straw building is inherently weak and will blow away, rot, burn or otherwise self-destruct and is a lazy and stupid choice of building materials.  In fact a properly built and maintained strawbale building will; last at least as long, if not longer than ‘modern’ building materials; is not subject to rotting or decay (unless poorly built) and can be used for construction of load bearing walls in multi-storey buildings (even under snow loading); is an excellent natural insulator for sound and heat with R ratings far higher than ‘modern’ insulated walls; and last but not least plastered strawbale walls are actually fire-resistant as proven in US forest and Australian bush fires. If you need another opinion to overcome 3 pig indoctrination Here’s a link to an Engineer giving his perspective on building with straw bales - whoever created the wolf and 3 pigs story has a lot to answer for!

“Modern era" Strawbale house building dates back to the early settlement of the United States from Europe and the invention of horse powered baling machines in the mid 1800’s.

Across the US midwest, and in Nebraska in particular, with little timber available in a sea of prairie grass, materials for traditional timber and brick house buildings were in short supply, so the use of baled straw from food crops for constructing houses was a practical solution for the settlers. 

These strawbale buildings were often built with load bearing strawbale walls, in snow country… several were multi-storey and many of these buildings are still in use today. 

In the 1970’s and 1980’s interest in eco building techniques liked rammed earth, adobe and strawbale grew and new building types like earthship’s were developed using a mix of old and new techniques and materials.  The early adopters were often hippies wanting to escape the suburbs and build their own dwellings, and while most were well built, they often did not seek/have building code compliance.  This was a time of experimentation and learning that supported later efforts to standardise and codify best practices for eco-building materials and construction methods.

In the 1980’s and 90’s awareness of the ecological, aesthetic and practical advantages of strawbale building grew, and licensed builders and structural engineers started the process of testing and codifying standards for strawbale construction.  These standard methods covered the construction of load bearing straw walls and non-load bearing straw walls (in-fill).  In practice most strawbale dwellings constructed from the 90’s onwards were post and beam in-fill type, as this method provides the primary benefits of strawbale building, while being simple to construct and most importantly with a lower perceived risk for the planning authorities to provide building consent.

As the materials and building methods started to gain planning authority approval, Architects were commissioned to design straw bale homes.  The first architecturally designed strawbale house built in New Zealand was 495 Kahuraniki Road in Hawke’s Bay, designed by the late Steve McGavock of Te Awanga.  It has a beautiful butterfly roof, massive walls and timber beams framing sweeping views along the Tuki Tuki river valley.  This house has inspired at least two straw bale house builds that I know of (ours being one) and I suspect many, many more…

Many strawbale houses have now been consented as accepted alternative solutions to local building codes all over the world. Strawbale homes feature on TV, for example in Grand Designs UK and Grand Designs NZ, and there are DIY workshops and specialist architects and builders.  While Strawbale building has been steadily edging towards mainstream building in the 2000’s the numbers of strawbale homes built per annum still remains very small in the overall scope of new homes built – so strawbale still remains an unusual and often architect designed alternative to choosing a standard home package.

Nga Kereru’s strawbale walls are built using timber frame ‘bucks’ with strawbale infill. 

The walls are topped with a perimeter plywood/timber box beam. 

The house has external and internal strawbale walls which are plastered with a clay finish inside and clay/lime outside. 

In addition to its natural beauty the plaster system is a great insulator for heat/sound, it is airtight but allows vapour to move in/out of the walls and last but not least it also adds to the thermal mass of the house.

Finally, the question you have probably been pondering all along.. is building with straw bales cheap?

The answer depends on many variables, as a building material yes, it is – in fact straw is burnt annually as a cropping waste product in many countries, but... baling straw and plastering it takes time and considerable effort... so if your labour is free then it’s cheap.  From an economic viewpoint labour is never free, there is always at least an opportunity cost of what you could have been doing productively in the same time.  From the viewpoint of an owner builder labour can be free and the time committed to building a joy rather than toil... so it all depends on how you look at it.  If you choose to employ someone else to build your strawbale house, you can expect the construction costs to be comparable with an equivalent sized timber frame house.  If you engage an Architect and want your own vision realised then there will probably also be consulting engineers involved and the costs do mount up quickly – but this is true of any custom build house project.

As noted at the start there are many variables…  our advice is to make a realistic budget based on your choices as early in the process as possible, keep refining it as your choices change and do get informed second opinions as you go.

Interested?? here are some links/references/people that we found helpful.

For general information and how to guides (USA) for strawbale building, see the following books and on-line resources:

The Straw Bale House; Athena Swentzell Steen, Bill Steen, David Bainbridge, David Eisenberg - Real Goods Independent Living

Design of Strawbale Buildings: The State of the Art; Bruce King – Green Building Press

www.strawbale.com; Andrew Morrison – StrawBale Innovations

For more information about Strawbale building in New Zealand, contact:

 Earth Building Association of New Zealand

Straw Home Hawkes Bay

If you are ready to design and build your own strawbale house in New Zealand, contact;

In today’s connected world Google and YouTube also provide a wealth of information about building with straw bales.

Things were a little different 25 years ago, when the three pigs had a lot more airtime than the strawbale builders… 

Have fun exploring!