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<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><?xml:namespace
prefix = o ns = "urn:schemas-microsoft-com:office:office"
/><o:p> </o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">I
am looking for advice on crawlspace humidity issues when the floor defines
the thermal barrier.<SPAN style="mso-spacerun: yes">
</SPAN><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><o:p> </o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">I
have a client that lives in a low spot in an urban neighborhood.<SPAN
style="mso-spacerun: yes"> </SPAN>Recent heavy rains and flawed city storm
drainage resulted in his crawlspace being flooded.<SPAN
style="mso-spacerun: yes"> </SPAN>Fortunately it did not reach the
floor.<SPAN style="mso-spacerun: yes"> </SPAN>However, the original
installation aspired to be a sealed crawlspace.<SPAN
style="mso-spacerun: yes"> </SPAN>It had plastic on the ground and coming
up the walls stapled to anchor plate below floor. Walls were covered by
fiberglass that was trashed in flood.<SPAN style="mso-spacerun: yes">
</SPAN><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><o:p> </o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">The
crawl space has ducts and a 15 year old forced air gas furnace.<SPAN
style="mso-spacerun: yes"> </SPAN>It appears to have survived the
flood.<SPAN style="mso-spacerun: yes"> </SPAN>I understand how to install
a better sealed crawlspace using foam instead of fiberglass.<SPAN
style="mso-spacerun: yes"> </SPAN>I also am encouraging him to insulate
the ground if he goes that route.<SPAN style="mso-spacerun: yes">
</SPAN>However, we are also considering removing the old furnace and ducts to
replace with a high efficiency mini split heat pump.<SPAN
style="mso-spacerun: yes"> </SPAN>This avoids the need HVAC equipment in
crawlspace.<SPAN style="mso-spacerun: yes"> </SPAN>Therefore, the thermal
barrier can be defined at the floor.<SPAN style="mso-spacerun: yes">
</SPAN>I have seen Journal of Light Construction report that floor installed
thermal barrier is more energy efficient than sealed crawl space.<SPAN
style="mso-spacerun: yes"> </SPAN>The installation they described did not
include insulation on the ground, however. With floor defined thermal barrier,
the efficiency would be even greater if no HVAC is located in crawl space.<SPAN
style="mso-spacerun: yes"> </SPAN>Also, this puts the installation out of
harms way if another similar event occurs again.<SPAN
style="mso-spacerun: yes"> </SPAN>The authors of the study article were
advocates for sealed crawl space that were dutifully reporting the results of
their study.<SPAN style="mso-spacerun: yes"> </SPAN>The main advantage for
sealed crawlspace is that the humidity is better managed with house HVAC system
than ventilation with outside humid air during hot time of year.<SPAN
style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><o:p> </o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">I
am considering recommending the floor bottom be sealed with closed cell
foam.<SPAN style="mso-spacerun: yes"> </SPAN>This would provide a vapor
barrier to protect the floor framing.<SPAN style="mso-spacerun: yes">
</SPAN>Currently the house is not cooled.<SPAN style="mso-spacerun: yes">
</SPAN>However, the mini split heat pump would provide this option.<SPAN
style="mso-spacerun: yes"> </SPAN>Therefore the conductive U value would
need to be low enough to avoid condensation on the warm humid crawlspace side
(bottom of floor) during the cooling season.<SPAN
style="mso-spacerun: yes"> I</SPAN>f all framing is covered with layer of
1or more inches of foam, are they protected from humidity?<SPAN
style="mso-spacerun: yes"> </SPAN>My assumption is that the masonry
foundation is not vulnerable to damage from humidity or similar flooding?<SPAN
style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><o:p> </o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">As
always, your thoughts are appreciated. <o:p></o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'"><o:p> </o:p></SPAN></P>
<P style="LINE-HEIGHT: normal; MARGIN: 0in 0in 0pt" class=MsoNormal><SPAN
style="FONT-FAMILY: 'Times New Roman','serif'; FONT-SIZE: 16pt; mso-fareast-font-family: 'Times New Roman'">Eli
<o:p></o:p></SPAN></P></DIV></BODY></HTML>