<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; color: rgb(0, 0, 0); font-size: 12px; font-family: Arial, sans-serif;"><div>Hi Art,</div><div><br></div><div>Off list I will forward documents on this subject (from UK and Australia) that were provided to me by John Fordice of the Cob Research Institute (CRI). I’m planning to use them as the basis for the thermal performance (thermal resistance and mass properties) for our cob code proposal. But with the review of Nehemiah Stone who is expert on thermal resistance and testing. He plans to first assess them for credibility at the end of May. </div><div><br></div><div>Nehemiah was instrumental in establishing the still-used R-value for straw bale walls for California while he worked at the California Energy Commission in the mid-nineties. I believe he is on the GSBN.</div><div><br></div><div>I didn’t hear R 1.25 per inch at the West Coast Natural Building Conference, but I’m highly skeptical. I’m even skeptical of R-0.8. </div><div><br></div><div>By comparison, the R-values Nehemiah and I settled on for straw bale walls in IRC Appendix S, based on the most reliable testing in the US, Denmark and the UK, are R-1.55/inch for bales laid flat and R-1.85/inch for bales on-edge. The values settled on for light straw-clay in IRC Appendix S by me, Paula Baker-Laporte and others on our LSC code team range from R-1.8/inch for density of 10 pcf, to R-0.84/inch for density of 50 pcf. As I remember, these are based on a USDA Forest Products Lab report, a testing report by the Canada Mortgage Housing Corporation and studies by research scientist Douglas Piltingsrud.</div><div><br></div><div>Cob density is always well above 50 pcf, and therefore should have a thermal resistance significantly less than R-.84 (if you trust the LSC values).</div><div><br></div><div>Martin Hammer</div><div><br></div><div><br></div><span id="OLK_SRC_BODY_SECTION"><div style="font-family:Arial; font-size:10pt; text-align:left; color:black; BORDER-BOTTOM: medium none; BORDER-LEFT: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 0in; PADDING-RIGHT: 0in; BORDER-TOP: #b5c4df 1pt solid; BORDER-RIGHT: medium none; PADDING-TOP: 3pt"><span style="font-weight:bold">From: </span> Gsbn <<a href="mailto:gsbn-bounces@sustainablesources.com">gsbn-bounces@sustainablesources.com</a>> on behalf of Art Ludwig <<a href="mailto:oasis@oasisdesign.net">oasis@oasisdesign.net</a>><br><span style="font-weight:bold">Reply-To: </span> GSBN <<a href="mailto:GSBN@SustainableSources.com">GSBN@SustainableSources.com</a>><br><span style="font-weight:bold">Date: </span> Tuesday, May 1, 2018 at 6:11 PM<br><span style="font-weight:bold">To: </span> GSBN <<a href="mailto:GSBN@SustainableSources.com">GSBN@SustainableSources.com</a>><br><span style="font-weight:bold">Subject: </span> [GSBN] R-values for cob, ideally documented<br></div><div><br></div><div><meta http-equiv="Content-Type" content="text/html charset=utf-8"><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hello people—</div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">I am working on getting our cob structures to pass Title 24 California Energy Efficiency requirements. Got this from Gord Baird:</div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><blockquote type="cite" class="">static heat flow of R 0.8 per inch, and a dynamic heat flow of R 2.0 per inch. </blockquote></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Anyone else have anything to contribute on the topic of R-values for cob? R 1.25 per inch was mentioned at the West Coast Natural Building Conference... </div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">The % of straw made an obvious difference in insulation value when we did fire resistance testing, but we did not translate this to an R-value. We could have up to 50% straw by volume in the mix (a bucket of loose straw per bucket of sand+clay). </div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""></div><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Gord’s $0.02:<br class=""><div class=""></div><blockquote type="cite" class=""><div class="">The R22 to R24 was full the whole house actual performance… but we had some walls at a steady state condition, and others in a dynamic condition.</div><div class="">There are two equally important numbers a static heat flow of R 0.8 per inch, and a dynamic heat flow of R 2.0 per inch. </div><div class=""><br class=""></div><div class="">Steady State: Assuming that there is no sun then cob will act at r 0.8 (with pumice or without). We had hoped the pumice would be more influential for insulation, but all it really provided was an additional R 0.2 over and above regular cob. It did provide a 2 fold increase in compression strength. Any cob wall in cloudy climates or north or shaded locations will act as a steady state performance - our home the North wall acted like the steady state value. We had hoped the pumice would be more influential for insulation, but all it really provided was an additional R 0.2 over and above regular cob. </div><div class=""><br class=""></div><div class="">Dynamic State: On the south wall, our 24 inch walls acted like R 40 due to the ability to readily accept and store the solar radiation… cob has a slower thermal radiation which means that even in colder climates like ours that the south wall is fairly useful as it can collect more energy than it can radiate it away. </div><div class=""><br class=""></div><div class="">Some of it is covered in this document <a href="https://ecosenseliving.files.wordpress.com/2011/09/science-research-report_sept_1.pdf" class="">https://ecosenseliving.files.wordpress.com/2011/09/science-research-report_sept_1.pdf</a> </div><div class=""><br class=""></div><div class="">A coincidence to get your email today… I had someone want to speak to me about greywater… and they were from Los Angeles. I sent them your way. I recall you were moving (or planning) on heading to the San Fran Bay area. </div><div class="">Cheers<br class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">Gord Baird<br class=""><a href="mailto:gord@eco-sense.ca" class="">gord@eco-sense.ca</a><br class=""><a href="https://eco-sense.ca/" class="">www.eco-sense.ca</a><br class=""><br class="">3295 Compton Rd.<br class="">Victoria, BC, V9E 1C8<br class="">Phn: 250-478-2680</div></div></div></div></blockquote><div class=""><div class=""><br class=""></div></div></div></div></div>_______________________________________________
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