Walls

Load-bearing strawbale walls were first built in Nebraska at the turn of the century. As a mark of respect to these pioneers I see no problem in remaining with the Nebraska method as a way of describing strawbale load-bearing walls.

The Nebraska method uses strawbales to bear the weight of the roof directly, i.e. the method is load bearing. The bales are laid in a running bond, much as bricks are laid but without the mortar. Although there are examples of running-bond strawbale homes with mortar used between each bale, this is both unsustainable and unnecessary.

Load-bearing walls require well-made bales that have a minimum calculated dry density of 7 pounds per cubic foot. Tight strings! That is, for the average Aussie bale we need a dry weight of 36 pounds or 16 kilograms. Calculate the dry weight of a bale by reducing the actual bale weight by the weight of the moisture content. The moisture content of a strawbale should not exceed 10% although 15% is acceptable. Most bales that we have tested have been well below 10%.

 
The common bale size is 900 mm long by 450 mm wide by 350 mm high.
Load-bearing bales should be laid on their flat.
Maximum height 5.6 to 1, e.g. a bale 450 mm wide will support a wall 2.520 high.
 
You will need to have ready the following sub-assemblies at the time you raise the walls:
   
termite protection barrier
moisture anti-wick barrier
top plates (see Top Plates section)
window and door frames (see Window and Door frames section)
lintels
roof assembly, e.g. trusses (see Roofs section).

 

               


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