After seeing problems in a few straw bale buildings, I’ve been thinking about this lately: is it a truly durable building system? By which I mean, will a straw bale house measure its lifespan in centuries rather than decades? I’ve concluded that most will, some won’t. The ones that won’t are predictable, however, and for the most part they break the rules. Architects occasionally design straw bale homes with no roof overhang, for instance. I’ve seen this twice, and in both cases an overhang was added before construction was completed. In one of them there were already some moisture issues
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Video of leveling earth plaster with a darby
Trever Miller from Evolve Builders came out and helped us with some plastering. I asked him to bring his darby (a three foot long leveling trowel) to help us level the kitchen wall behind the cabinets. Trever has years of experience leveling walls with a darby, I filmed this video of him at work.
Continue readingWindow shaping in straw bale homes: a how-to and slideshow
Window curves are one of the most distinctive features in straw bale homes, and are often a big consideration in the choice to go with straw bale over other forms of construction. But information on how to shape curves is sparse, so I thought I’d share some of what we’ve learned over years of doing bale work. The first thing you really need to think about is radius of curve. To visualize this take a string nine inches in length, pin it at one end and attach a pencil to the far end. Now draw a quarter of a circle
Continue readingNotes on toxicity
People who are new to natural plasters sometimes think they are non-toxic: earth plasters are made out of materials dug from the ground, right, how could they be dangerous? In fact, while the end result is non-toxic, these products can still be hazardous to work with. Take clay for instance, which often contains large amounts of crystalline, or ‘free’, silica (fine quartz), which when inhaled causes silicosis (a debilitating lung disease) and lung cancer. Silica is also found in cement and fine sand, but not in pure lime (which nevertheless isn’t great to breathe in). The long and the short of it is that plasterers work with
Continue readingStraw Bale Building checklist
Recently my friends asked me for advice on building a small straw bale building (a garage with a living space above). They asked me how it will compare, timewise, to conventional framing. The answer: it will definitely take longer. They will save money on materials (some) but it will only be worth it if they really want the extra insulation value. They do, and they want to try building with bales as a test run for a future house. Also they want to use post and beam anyway, which means they need some kind of secondary wall system – for
Continue readingHow to make clay slip
Earth plasters are wonderful because you can use soil that was dug from your foundation, or a truck can deliver a load of clay soil that was dug from another construction site. But anyone who has a pile of clay soil sitting on their jobsite knows that it’s hard to process. It can be rock hard, or incredibly sticky globs, and often contains stones that need to be sieved out. Here’s how to process clay into slip for use in earth plasters. You need a very good drill that can withstand running for hours, and a barrel with one end open. Fill the barrel
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