<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"><div><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)" size="1"><font size="2">202-437-8583</font></font><font style="color:rgb(102,102,102)" size="1"><font size="2"><br>
<a style="color:rgb(102,102,102)" href="mailto:alan@abramsdesignbuild.com" target="_blank">alan@abramsdesignbuild.com</a><br style="color:rgb(102,102,102)"></font></font><a href="http://www.heliconworks.com/index2.html" target="_blank">HELICON WORKS <i>Achitecture and Education</i></a></div></div></div></div>
<br><div class="gmail_quote">On Fri, Jun 12, 2015 at 2:55 PM, Leslie Moyer <span dir="ltr"><<a 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 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>
_______________________________________________
<br>
Greenbuilding mailing list
<br>
to Send a Message to the list, use the email address
<br>
<a href="mailto:Greenbuilding@bioenergylists.org" target="_blank">Greenbuilding@bioenergylists.org</a>
<br>
<br>
to UNSUBSCRIBE or Change your List Settings use the web page
<br>
<a href="http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org</a>
<br>
</blockquote>
<br>
</blockquote>
<br>
<br>
</span><span class="HOEnZb"><font color="#888888"><div>-- <br>
<b>Leslie Moyer</b>
<br>
Email: <a href="mailto:unschooler@lrec.org" target="_blank">unschooler@lrec.org</a>
<br>
Phone: (918) 772-6150
<br>
Cell: (918) 633-8820
<br>
<br>
Sustainable Tahlequah
<br>
Web: <a href="http://www.SustainableTahlequah.org/" target="_blank">SustainableTahlequah.org</a>
<br>
Discussion List: <a href="http://groups.yahoo.com/group/SustainableTahlequah" target="_blank">groups.yahoo.com/group/SustainableTahlequah</a>
<br>
</div>
</font></span></div>
<br>_______________________________________________<br>
Greenbuilding mailing list<br>
to Send a Message to the list, use the email address<br>
<a href="mailto:Greenbuilding@bioenergylists.org">Greenbuilding@bioenergylists.org</a><br>
<br>
to UNSUBSCRIBE or Change your List Settings use the web page<br>
<a href="http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org" rel="noreferrer" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org</a><br></blockquote></div><br></div>