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<div class="moz-cite-prefix">And how would you propose we get rigid
mineral fiber insulation into my 2'x2' crawl space entry? That's
if I'm being generous....<br>
<br>
On 6/12/15 2:17 PM, Alan Abrams wrote:<br>
</div>
<blockquote
cite="mid:CADj3_s4aQ-SxZVYg0HFN4Cc-oPettoYi2vhGweH3R-xpPmsPrA@mail.gmail.com"
type="cite">
<div dir="ltr">Hi Leslie
<div><br>
</div>
<div>somehow I don't like the idea. I assume the insulation
contractor is proposing to apply foam to the underside of the
floor sheathing. If that is the case, there is the possibility
of the exposed portion of the joists getting below dew point,
and becoming saturated with condensed water vapor. IIRC, Joe
Lstiburek has some really ugly photos of this condition.<br>
<br>
my preference (at a minimum) would be to seal and insulate the
perimeter of the floor cavity with caulk and batts, and apply
a smart membrane (like MemBrain) to the underside of the
joists, carefully lapped and taped, and then some rigid
mineral fiber insulation under that. Fire resistant, mold
resistant, thermal bridge resistant, and semi permeable. The
crawlspace can then behave or misbehave as it pleases, without
impact on IAQ</div>
<div><br>
</div>
<div>-aa</div>
</div>
<div class="gmail_extra"><br clear="all">
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<div class="gmail_signature">
<div dir="ltr"><font size="2"><font size="2"><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
size="2"><span style="color:rgb(102,0,0)"><font
color="#666666"><i><br>
</i></font></span></font><font
style="color:rgb(102,102,102)" size="1"><font size="2">cell
</font></font><font style="color:rgb(102,102,102)"
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target="_blank">alan@abramsdesignbuild.com</a><br
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</font></font><a moz-do-not-send="true"
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Education</i></a></div>
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<div class="gmail_quote">On Fri, Jun 12, 2015 at 2:55 PM, Leslie
Moyer <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:unschooler@lrec.org" target="_blank">unschooler@lrec.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>Yeah, well, I considered that option first and was
ridiculed for that on this list several months ago. My
crawl space is tight (for humans), but well-ventilated,
so I'm going to go with this option as I think it is the
most practical.<br>
<br>
--Leslie<span class=""><br>
<br>
On 6/12/15 1:18 PM, Frank Tettemer wrote:<br>
</span></div>
<span class="">
<blockquote type="cite">Hi Leslie, <br>
<br>
You may want to re-consider the idea of foaming the
floor in a crawl space. My concerns would be that the
foam would act too well as a vapour barrier, and you
may have moisture/mildew problems down the road in the
crawl space. I AM in Canada, so your geographic
climate might create different problems than here. <br>
<br>
I always design any neccessary crawl spaces as a
definite part of the conditioned space of the home.
That means insulating the walls and the floor of the
crawl space, and leaving the floor as a vapour-open
plane, as well as including the crawl space in the
heating design. This avoids condensation trouble, by
keeping the air warm and dry. <br>
<br>
Frank <br>
<br>
Frank Tettemer <br>
Living Sol ~ Building and Design <br>
<a moz-do-not-send="true"
href="http://www.livingsol.com" target="_blank">www.livingsol.com</a>
<br>
613 756 3884 <br>
<br>
<br>
On 12/06/2015 2:02 PM, Leslie Moyer wrote: <br>
<blockquote type="cite">I am in NE Oklahoma. I'm in
the process of getting estimates for crawlspace
insulation in the floor joists--closed cell foam.
My crawl space is dry now that we've fixed some
plumbing problems, but I'm having some cupping
issues with some wood flooring and part of the
fiberglass batts that were originally in the house
when we bought it were taken out over time for this
and that. Anyway--closed cell foam seems to be the
best solution. <br>
<br>
The first guy who came this morning wants to quote
me 1.5" foam, though said he would quote 2" if
that's what I really want, saying that would be
enough for "Canada". I understand about the
benefits of air sealing, but I was still thinking I
would need more inches of foam according to what
I've read on R-value & this area. Thoughts? <br>
<br>
-- <br>
*Leslie Moyer* <br>
<br>
<br>
<br>
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</blockquote>
<br>
</blockquote>
<br>
<br>
</span><span class="HOEnZb"><font color="#888888">
<div>-- <br>
<br>
</div>
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