<div dir="ltr"><span style="font-family:arial,sans-serif;font-size:13px"><Logically, the interior wall would be the one designated as load-bearing even if only because doing so shortens the spans of flexural members like joists and rafters. When we're talking about fat superinsulated walls, the difference in span can mean a difference in one joist size.></span><br>
<div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px">taking off from the perspective pasted above, one could quickly arrive at a Larson type system, where you not only shorten the span of the floor system, but eliminate it altogether beyond the bearing wall.</span></div>
<div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px">OTOH, if the premise is keeping the air barrier in a single vertical plane--and factoring in the current code obsession with braced wall systems--I still prefer keeping the air barrier and sheathing--and therefore the outer stud wall, in a constant plane. all the other previous points reinforce this--logical integration of windows and doors, combining air barrier and drainage plane--not to mention--keeping it low tech and carpenter friendly.</span></div>
<div><span style="font-family:arial,sans-serif;font-size:13px"><br></span></div><div><span style="font-family:arial,sans-serif;font-size:13px">The point about reducing joist depth is well taken: there is value in "resourcing down." But it is less significant if you're using wood I-beams. A tree that could provide a nice 2x12 is best left in the forest, but a little more OSB to take a TJI from 9 1/2" to 11 7/8" is less of an impact.<br>
<br>It's worth mentioning that this strategy derives from Building Science Corp's design for the NIST Net Zero Energy Test House--a sublime piece of work, IMO...<br><br>-AA</span></div></div><div class="gmail_extra">
<br clear="all"><div><font><font><span style="color:rgb(102,0,0)">Alan Abrams</span></font><b style="color:rgb(102,0,0)"><br></b><i><span style="color:rgb(102,102,102)">certified professional building designer, AIBD<br>certified passive house consultant, PHIUS</span></i></font><div>
<i><span style="color:rgb(102,102,102)">certified passive house builder, PHIUS</span></i><font><span style="color:rgb(102,0,0)"><font color="#666666"><i><br></i></font></span><font><span style="color:rgb(102,0,0)">Abrams Design Build LLC</span></font><font size="4"><br style="color:rgb(102,0,0)">
<font><i style="color:rgb(102,0,0)">sustainable design for <font>intentional</font> living</i></font></font></font><font style="color:rgb(102,102,102)" size="1"><font><br></font></font><font style="color:rgb(102,102,102)" size="1"><font>cell </font></font><font style="color:rgb(102,102,102)" size="1"><font>202-437-8583</font></font><font style="color:rgb(102,102,102)" size="1"><font><br>
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<br><br><div class="gmail_quote">On Thu, Mar 27, 2014 at 9:11 AM, Clarke Olsen <span dir="ltr"><<a href="mailto:prismoidal@gmail.com" target="_blank">prismoidal@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
The problem with single top headers is that, when triaging the lumber, it's hard to find something you feel can be trusted up there all alone... 2x3 sounds better then it is: most of them are crap. The other reason to make the interior studs bearing is that you can keep the foundation back, leaving a very generous overhang to drip past the foam that covers your foundation. I used to think I was a hero for putting 2" of blueboard under the slab and against the foundation, until I noticed how nice & cool it was in summer...<br>
<span class="HOEnZb"><font color="#888888">Clarke Olsen<br>
<a href="http://clarkeolsendesign.com" target="_blank">clarkeolsendesign.com</a><br>
373 route 203<br>
Spencertown, NY 12165<br>
USA<br>
518-392-4640<br>
<a href="mailto:colsen@taconic.net">colsen@taconic.net</a><br>
</font></span><div class="HOEnZb"><div class="h5"><br>
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On Mar 26, 2014, at 5:55 PM, RT <<a href="mailto:archilogic@yahoo.ca">archilogic@yahoo.ca</a>> wrote:<br>
<br>
> On Wed, 26 Mar 2014 11:42:01 -0400, AA-man wrote:<br>
><br>
>> here's where I'm heading ...*OVE stud wall<br>
>> *a void, width determined by specific space heat demand analysis<br>
>> *an inner frame wall<br>
>> *the entire framing cavity filled with DP cellulose<br>
><br>
><br>
> The above sounds very much like a double-stud wall section so one should choose which of the two frame walls is load-bearing .<br>
><br>
> Logically, the interior wall would be the one designated as load-bearing even if only because doing so shortens the spans of flexural members like joists and rafters. When we're talking about fat superinsulated walls, the difference in span can mean a difference in one joist size.<br>
><br>
> In making the interior wall loadbearing, there's no need for the exterior wall to be a 2x6 OVE stud wall -- it can be a 2x3 or 2x4 wall with studs at 24" o/c, single top plates, no lintels over openings (assuming that we're talking about low-rise residential building)<br>
><br>
> One just needs to ensure that one allows for eventual shrinkage of cross-grain framing members (ie sill & top plates, rim joists, lintels) in the bearing wall so that the curtain wall does not inadvertantly become loadbearing.<br>
> --<br>
> === * ===<br>
> Rob Tom AOD257<br>
> Kanata, Ontario, Canada<br>
><br>
> < A r c h i L o g i c at Y a h o o dot c a ><br>
> (manually winnow the chaff from my edress if you hit "reply")<br>
><br>
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