Congrats Chris!! great to hear about all your great projects when you were here, thanks again for coming, hope to visit up there someday! Given this thread, thought I would post that we just did our final test on our straw bale passive house here in Boulder, Colorado. We used a typical 10 ml plastic vapor/radon retarder under the slab, Huber Zip System sheathing on the roof which was taped down onto the box beam, and NHL plaster on the walls. The result was about .5ACH50. The windows we used were tiple pane, aluminum clad wood insulated Zola European windows (R11.36 cog, .5SHGC, R 6.31 frames) with zip tape to the solid wood bucks on the interior. we are now using Siga swiss tapes instead on the interior. <div>
<br></div><div> The problems we found in air tightness were at the foundation joint and several lighting penetrations that did not repair the air barrier after being installed - in the future, we will gasket this under the plaster J-strip so there is not air leakage between the plastic vapor barrier under slab/walls and the end of the plaster. Otherwise, I found the lime plaster to be virtually airtight. We tested a 2500 sf straw bale house with vaulted ceilings, at 190CFM@50. It was not the plaster that appeared to be leaking, but the joints where plaster went to other materials. I am convinced our earth plaster projects will perform just as well. I am very interested in building a typical 2x4 frame building with wood diagonal 1x sheathing and then a continuous air barrier of burlap and clay plaster for the air barrier with a 14" bales on edge wrap and may have a project next year in this fashion. I have been inspired by the Austrian passive house straw bale wrap over cross laminated timber -if you haven't seen it: <a href="http://www.s-house.at">www.s-house.at</a><br>
<br><div class="gmail_quote">On Tue, Nov 13, 2012 at 8:07 AM, Chris Magwood <span dir="ltr"><<a href="mailto:chris@endeavourcentre.org" target="_blank">chris@endeavourcentre.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Thanks all!<br>
<br>
John, it's good to hear that the range to aim for is between 1-2 ACH@50. I wasn't sure where the Passive House number came from, but I was attempting to get there just because I've talked to so many PHers who have told me there's no way to get there with bale walls, and especially not with clay plasters. But if we're in the right zone to be a good low energy house, then I'm happy with that!<span class="HOEnZb"><font color="#888888"><br>
<br>
Chris</font></span><div class="im HOEnZb"><br>
<br>
On 12-11-13 8:02 AM, John Straube wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Well done Chris!<br>
Although it seemed possible in theory (at least I always said so) it is great to get some real confirmation to be definitive.<br>
Getting to 1 ACH@50 is a real accomplishment in any housing type.<br>
A tiny bit of air will likely leak through some earth plasters (especially if they have straw in them) as we now have found that a tiny bit of air leaks through some plywood and OSB. Maybe 0.2 or or 0.3 ACH@50 worth. This is not really a performance issue, but it happens.<br>
It is hard to get to 1 ACH@50 without really good windows, so you likely have those (casements in Canada tend to be good, double hungs in the US are routinely leaky).<br>
It is also important to remember that there is nothing magic about 0.6ACH@50, it is just a number someone picked. While tighter is always better, as I speak to more people at the edge of advanced housing and they gain experience the more it seems that numbers between 1 to 2 ACH@50 look like a good spot to be. There is almost no benefit to going from 1 down to 0.5 and there starts to be some odd effects (like challenges with exhaust range hoods, bath fans etc) as we get to the 0.2 to 0.6 range (effects we have learned more about as people target those numbers).<br>
Suffice it to say, you have shown that you get as tight as needed for a low-energy, healthy and comfortable home, even in very cold places.<br>
<br>
</blockquote>
<br></div><div class="im HOEnZb">
-- <br>
Chris Magwood<br>
Director, Endeavour Centre<br>
<a href="http://www.endeavourcentre.org" target="_blank">www.endeavourcentre.org</a><br>
<br></div><div class="HOEnZb"><div class="h5">
______________________________<u></u>_________________<br>
GSBN mailing list<br>
<a href="mailto:GSBN@sustainablesources.com" target="_blank">GSBN@sustainablesources.com</a><br>
<a href="http://sustainablesources.com/mailman/listinfo.cgi/GSBN" target="_blank">http://sustainablesources.com/<u></u>mailman/listinfo.cgi/GSBN</a><br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><b><font color="#666666">Brian Andrew Fuentes, AIA, Certified Passive House Consultant</font></b><br><div style="color:rgb(80,0,80)"><b><font color="#993300">fuentesdesign | natural architecture</font></b></div>
<div><span style="font-size:x-small"><br></span></div><div><span style="font-family:Arial,sans-serif;text-align:left;background-color:rgb(255,255,255)"><font size="1">303 532 5723 office</font></span></div><div style="text-align:left">
<font face="Arial, sans-serif" size="1">303 523 4654 mobile</font></div><div><div><font size="1">303 309 0351 fax</font></div><div><br></div></div><div><div>Mailing Address:</div><div>812 20th Street #9<br>Boulder, Colorado 80302</div>
<div><br></div><div>Office:</div><div>5171 Eldorado Springs Drive</div></div><div>Boulder, Colorado 80303</div><div><br></div><br>
</div>