<div dir="ltr">Thanks a lot Andy.</div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Oct 24, 2013 at 3:41 PM, Andy Horn <span dir="ltr"><<a href="mailto:andy@ecodesignarchitects.co.za" target="_blank">andy@ecodesignarchitects.co.za</a>></span> wrote:<br>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Dear Anthony<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Afraid this comes as a rather delayed response, in regards your
question about the long term preservation of straw in clay.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Firstly I think is worth said that Bruce King’s book “Design
of Straw Bale Buildings – The State of the Art” explains the
science of it all rather perfectly. As for research documents I cannot help but
I nonetheless thought a few tales were worth sharing <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Firstly I know an artist, Peter Eastman who used to work in the
antiquities department of the British Museum doing restoration work. He told me
about how unbaked clay can preserve straw perfectly for thousands of years. He
says that when restoring many old Egyptian sculptures, the easiest were the
ones made of unbaked clay, which many of them were. He said that when working
with them they would simply break down any shards of clay rewetting it to
remould broken limbs and such back together again. He said that something that
had always amazed him when busy with such works, was that he would find bits of
sparkling yellow straw in the clay and that despite its 1000’s of years
of age, nonetheless looked as fresh as if it had just been harvested. <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The second was when I was travelling in a rather more humid
Japan. In Kyoto, I chanced across a demolition in progress of an old
traditional Japanese “wattle and daub” house. The old construction,
which could have been anything from 100 – 500+ years old consisted of a timber
frame with infill panels of timber and bamboo lattice work with a cob infilling,
which had a natural plaster on the one side and originally a timber cladding on
the exterior. Upon examination I noticed how the straw (rice straw no doubt) in
the cob used in the construction still looked and performed as new. The
contractors were dampening the place down with water while they bashed the construction
to the ground (sadly there are no heritage conservation laws in Japan that
protect old buildings) so I took handfuls of the damp cob and worked it as if
it were just newly made. I have attached some photos of the straw clay
bamboo construction and another revealing the construction – which
hopefully the server will allow..? If not then I will need to upload it
onto media fire and send out a link.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">It was also interesting to note how vital moisture levels and air
exchange is to the survival of straw rather than age per se. After taking the
demolition photos, wanting to take a specimen with me, I snatched a sample of
the old somewhat sodden sample of the clay and final plaster layer. Looking
around I grabbed a handy piece of plastic and wrapping it up safely, stuffed it
in my pack and then forgot about it. That is until finally a couple of weeks
later when back home I unfurled the by now mouldy packet. To my dismay all the
straw had moulded away to nothing. The samples were wet and because the
wrapping did not breath, of course rot set in, ironic I thought after surviving
perfectly for hundreds of years beforehand.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I have also observed in demolitions of old works how timber that
is buried in clay, will be well preserved especially in comparison with
timber that has been laid in concrete, which will normally be rotted away.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Best regards<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Andy Horn<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Eco Design – Architects & Consultants<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">A. R. Horn </span><span style="font-size:8.0pt;font-family:"Calibri","sans-serif";color:#1f497d">BAS, B. Arch, Pr Arch, MIA </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1f497d">1<sup>st</sup> floor 79 Roeland Street, Cape Town, South Africa<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a href="tel:%2B27%2021%C2%A0462%201614" value="+27214621614" target="_blank">+27 21 462 1614</a>, <a href="http://www.ecodesignarchitects.co.za" target="_blank">www.ecodesignarchitects.co.za</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:GSBN-bounces@sustainablesources.com" target="_blank">GSBN-bounces@sustainablesources.com</a>
[mailto:<a href="mailto:GSBN-bounces@sustainablesources.com" target="_blank">GSBN-bounces@sustainablesources.com</a>] <b>On Behalf Of </b>Anthony Dente<br>
<b>Sent:</b> 27 September 2013 10:45 PM</span></p><div class="im"><br>
<b>To:</b> Global Straw Building Network<br>
</div><div class="im"><b>Subject:</b> [GSBN] Straw Preservation in Clay _ Research Documents<u></u><u></u></div><p></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Hello Everyone,<u></u><u></u></p><div><div class="h5">
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">I hope your Septembers are coming to a pleasant close.
I'm curious if any of you could point me in the direction of reports
documenting the long term preservation of straw in clay plasters, cob walls, or
similar. Most importantly it's tensile characteristics.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">I have been aware for some time of the "common
knowledge" that wicking qualities of clay's hydrophilic nature preserves
such biodegradable materials and that this is the backbone of many clay
building techniques. I have even spoken with colleagues and friends who
say they have chipped open buildings and felt these qualities themselves.
Though I am unable to locate studies/reports documenting significantly
old structures (preferable in rainy climates) that have had boring tests done
and confirm this.<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Thanks for any and all of your help,<u></u><u></u></p>
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<p class="MsoNormal">Anthony<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Anthony Dente, PE, LEED AP<u></u><u></u></p>
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<p class="MsoNormal">Kevin Donahue Structural Engineers<u></u><u></u></p>
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<p class="MsoNormal">Berkeley, CA<u></u><u></u></p>
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<p class="MsoNormal"><a href="tel:814.502.6001" value="+18145026001" target="_blank">814.502.6001</a><u></u><u></u></p>
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