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<TITLE>Re: [GSBN] straw bale dimensions - Hand made bales</TITLE>
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<FONT FACE="Arial"><SPAN STYLE='font-size:10pt'>Hello Andy,<BR>
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Glad to hear things are progressing. Given my experience with the handmade bales in Pakistan and Haiti, I recommend 12”x12”x24” (300mm x 300mm x 600mm) bales. I wouldn’t go much less, especially if insulation is an issue (for heating climates). And during construction it feels like a wall any thinner might be pushing it in terms of structural stability for an 8’ (2450 mm) high wall for load bearing walls. <BR>
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That said, in tropical climates like Haiti, where insulation isn’t so important (although still an issue for keeping the interior cool, or even warm in the mountain regions) Andy Mueller and I discussed how small we think we could go, in order to be more resource efficient. We’ve considered trying 10”x10”x20” (250mm x 250mm x 500mm) bales, but haven’t tried yet. Going this thin or thinner you would have to see what works for out-of-plane stability. Either with some type of mesh, or the frequency of external pinning (presumably bamboo where you are). On the other hand, if this is post and beam with straw bale infill, it makes the prospect of thinner bales (even less than 10”, 250mm) more plausible. <BR>
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Regardless of the thickness, I like the length to be twice the thickness for a good running bond and ease of turning corners. Also, when making your own bales I like the thickness to be the same as the “height”. Or I can’t think of a good reason to do otherwise. If nothing else you can put bales “flat” or “on-edge” and they are the same thickness and height. I’ve found there are sometimes reasons to mix the orientations within the same wall or building. <BR>
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One other thought on going small with bales, at some point smaller bales mean more labor and hassle dealing with more units (even though you might be saving material). I’m not sure where the threshold of diminishing return is, but I suspect it’s somewhere around the 12” (300mm) or maybe the 10” (250mm) thickness. I suppose one could also experiment with thin bales with a length three times their thickness, in order to have fewer units, but I think they might become flimsy.<BR>
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My experience tells me the same density as “normal” bales works well for small bales (7-8 lb/cu.ft or 110-130 kg/cu.m). <BR>
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This brings up the proprietary Oryzatech Stak Block, which are highly compressed, self binding, interlocking, and 12”x12”x24” (300mm x 300mm x 600mm). Being developed by a California architect and entrepreneur, I think the material/system has great promise but it hasn’t gotten off the ground yet. This is a whole other subject, but is worth seeing at <a href="http://www.oryzatech.com/stakfacts.html">http://www.oryzatech.com/stakfacts.html</a><BR>
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I hope this helps. Darcey or Andy might have opinions also. My best advice is to experiment for your circumstances, and trust your observations and instincts. <BR>
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Best.<BR>
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Martin<BR>
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On 3/5/12 7:31 AM, "Andy Horn" <<a href="andy@ecodesignarchitects.co.za">andy@ecodesignarchitects.co.za</a>> wrote:<BR>
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</SPAN></FONT></FONT><BLOCKQUOTE><FONT FACE="Arial"><FONT COLOR="#008000"><SPAN STYLE='font-size:10pt'>Hi all <BR>
The project in the highlands of Lesotho, which I got some excellent input on from the Network – thanks especially to Darcey Donovan and Habib – for making hand made bales using a lorry jack press is at last staring to inch forward.<BR>
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The project manager is trying to get a prototype together for the press design and is asking how small he can go with a bale….<BR>
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I am not familiar with small bales and our typical standard 2 string bales here are typically 900mm long x 450mm wide x 350mm high. Smallest I would say I have come across were as I recall about 850 long x 420mm wide by 340mm high. (Sorry no imperial dimensions for those of you in the States…as we into metric system here).<BR>
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Any input about if one goes smaller and what are the rules???<BR>
Does one need to and can one make a more compact bale if one goes smaller?<BR>
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Is there a recommended / ideal size for making hand pressed bales.<BR>
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Kind regards,<BR>
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</SPAN></FONT><FONT COLOR="#008000"><SPAN STYLE='font-size:10pt'>Andy Horn<BR>
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