Straw bale construction is not a new concept by any stretch of the imagination. In centuries gone by, villagers in rural areas would use straw bale construction to build their home and found that their straw structures would stand up to the tests of time and weather.
However, this method of building was largely forgotten when brick structures were introduced and society became a bit more affluent. That is not to say that straw bale construction has not begun to enjoy its former popularity in modern society because it has, largely thanks to the fact that it is an environmentally friendly way of building your own home.
Of course, straw bale construction can be used for outhouses and walls as well as houses, but the method behind it is the same no matter what you are building.
The Advantages Of Straw Bale Construction
Straw bale construction does have many advantages over conventional and accepted building techniques today. First and foremost, it is extremely environmentally friendly.
The straw is of course completely natural and bio-degradable, eventually when you do wish to dispose of it! You are also taking nothing away from the earth by using it as a building material because it is completely sustainable. It is also readily available!
Secondly, straw is extremely cost effective. It can produced and harvested very cheaply and thus would cost very little if you did decide to construct a home made out of it. It is much cheaper than other building materials out there. A basic 2,000 square-foot house requires about 300 standard three-wire bales of straw, cost: approximately $1,000.
It is also cost effective when it has been transformed into a building because straw is an excellent insulator, meaning that it will keep the heat in and thus save you money on your heating bills as well. Straw is a form of cellulose insulation that has fairly good insulating properties.
Since each bale can be up to two feet thick, a straw bale wall has very high thermal resistance. Recent tests following ASTM procedures resulted in bale R-values between R-2.4 and R-3.0 per inch, depending on the direction of the straw
The Building Blocks
The building blocks of straw bale construction are not that complex so it is quite conceivable that you could build your own home, outhouse or wall from scratch with your family and friends. Your home or structure will need a foundation, as any other structure would so it is advisable that you dig at least 4 feet deep after planning out exactly where the structure will go. When the foundations are in place, you can get on with the actual building.
The straw bales that you should build when building are not regular bales but high density ones that have appeared on the market in recent years as a result of the increased demand for straw bale construction.
The higher density bales are a little more appropriate for building because they keep the weather out a little bit better, and are sturdier and bear far more pressure than regular bales. They are put into bale form at the source so you do not have to do it yourself. All you have to do is obtain the bales and get them to your building area.
You literally build the walls by stacking the bales one on top of the other. They should be joined internally with bamboo pins or wire meshes. Both materials also bear a lot of pressure and will stand the test of time by keeping the bales snug and united as one. When the walls are up then you should use a layer of cement on the inside walls to keep the elements out and the straw firm throughout the years.
Of course, the construction is not quite as simple as that but the straw bale construction you undertake will vary from structure to structure. Every one is different and should be researched in advance because there are different techniques and methods used. However, the basic principles are the same and so you should be more than able to build your own cheap home that will stand the test of time.
For more details:
Development Center for Appropriate Technology. Consulting, education, testing and research, networking.
The Canelo Project Basic information on straw-bale building.
Photo by Peter Lenardon, Creative Commons Attribution License