Strawbale

Strawbale

Strawbale building has seen widespread growth as it progresses into the building world. This is largely due to the standardization that is possible with the use of a fairly consistent building material: the straw bale. Because a bale of straw is a bale of straw most anywhere (well, close enough anyway), this building method has made its way into code!

Strawbale houses are built by stagger-stacking bales of straw and then “pinning” them together. These pins may be either internal or external and vary from rebar rods to wood or bamboo. Personally I stay away from rebar, but engineers may sometimes call for metal to be used in various phases of the building. Work with your engineer kindly and you may find that bamboo, or other materials, may be approved instead.

There are a number of ways you can stack your bales of straw. Somewhat surprisingly perhaps is that this can have an effect on the levels of insulation. Stacking the bales on their sides, with the straws running up and down, provides for a higher insulation value even though the walls are thinner. For me this is win-win. However, this requires very solid pinning, as the bales can be a little less stable stacked on their skinny sides. Alternatively, are also often stacked on their flatter and wider bottoms, with the straws running horizontally. This requires less intensity to be placed on the pinning, but also lowers the insulative values and adds thickness to your walls. I have also seen bales staked on their ends, but this didn’t seem like a great design in my personal opinion. However, this does come in handy when fitting a bale into a smaller space once in a while.
Strawbale is also load-bearing, though many people find it goes well with a stout timber frame.

There is also the option of pre-dipping your bales in a clay slip, or putting them up dry and covering them in slip later. Personally I prefer the pre-dip and this saves time later and gets everyone involved good and dirty!

Dipping the exposed ends of the strawbale in clay slip before stacking it on the wall.

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