Top 7 Straw Bale Mistakes
Given I first started my straw bale construction business in 1991, I must admit that I learned a lot of mistakes the hard way: by making them. So here’s a list that came to my mind when I was asked by a fellow builder what I thought the top straw bale mistakes were. The list is not given in any necessary order.
1) Covering straw bales with some kind of non-breathable material prior to plastering, thus not allowing bales to transpire moisture.
2) Doors, windows, and other openings are poorly insulated; plaster cracks, moisture and insects penetrate in the weakest areas of the straw bale building.
3) Insufficient use of a good external plaster(usually stucco in the Southwest United States), thus not protecting the bales from external damage and in the case of straw bale walls, not giving the structure enough structural integrity.
4) Lack of sufficient design: in terms of houses, not allowing enough drainage away from the building to prevent water penetration into the bales; insufficient overhang, roof overhangs, poor choice of placement of structure on building site which may or may not allow for natural drainage, vegetation within the vicinity to shade or heat the building, not allowing use of passive solar gain, etc.
5) Poor integration between straw bale wall and ceiling; insufficient placement of loose straw bale flakes in-between the bales themselves, thus compromising the natural insulation value (R-value) of the material.
6) Insufficient placement of straw bale reinforcement, namely stucco netting, which can cause structural failure of the sheathing (plaster), which can lead to a host of other failures.
7) Insufficient plaster. Ie using an adobe that has insufficient aggregate proportion, or using a stucco that has a bad ratio of sand to cement.
As you can see, openings and plaster are crucial parts of the straw bale construction process. It is imperative that the entire straw bale house is sealed as tightly as possible and that all loose areas or openings are packed tightly with straw. Plastering is a time-consuming art, and has taken decades for us to develop the right system. If you’re an owner-builder experiencing a straw bale problem, or are looking into building a straw bale home, please feel free to
contact us at any time.