<HTML xmlns="http://www.w3.org/TR/REC-html40" xmlns:v =
"urn:schemas-microsoft-com:vml" xmlns:o =
"urn:schemas-microsoft-com:office:office" xmlns:w =
"urn:schemas-microsoft-com:office:word" xmlns:m =
"http://schemas.microsoft.com/office/2004/12/omml"><HEAD>
<META content="text/html; charset=us-ascii" http-equiv=Content-Type>
<META name=Generator content="Microsoft Word 14 (filtered medium)">
<STYLE><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:"Baskerville Old Face";
panose-1:2 2 6 2 8 5 5 2 3 3;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></STYLE>
</HEAD>
<BODY lang=EN-US dir=ltr link=blue vLink=purple>
<DIV dir=ltr>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial'; COLOR: #000000">
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'>
<DIV dir=ltr>
<DIV style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial'; COLOR: #000000">
<DIV><FONT face="Times New Roman"><FONT size=4>
<DIV
style='FONT-SIZE: small; TEXT-DECORATION: none; FONT-FAMILY: "Calibri"; FONT-WEIGHT: normal; COLOR: #000000; FONT-STYLE: normal; DISPLAY: inline'><FONT
size=4 face="Times New Roman">My standard detail for exterior wall framing is a
stud wall at with structural sheathing to exterior covered with 6”+- eps foam
with seams sealed with Pur Stick. 2x3 furring strips aligned with studs
with 9” headlock screws with sealant on foam side of furring strip to seal the
hole created by screw</FONT>. T</DIV>he 2x furring strips allow
conventional nails to be used. Using 3/4” plywood is an alternative that
requires screw fastening of siding. I like the wider space of the
2x. </FONT></FONT></DIV>
<DIV><FONT size=4 face="Times New Roman"></FONT> </DIV>
<DIV><FONT size=4 face="Times New Roman">My question is with this assembly, is
it necessary or beneficial to add a layer of building wrap above to the exterior
of the eps foam. I prefer eps to xps because it is vapor permeable and an
air barrier. This is the benefit of building wrap. The thickness of
foam makes the air warmer on the warm side, reducing the threat of
condensation. On my own home retrofit, over existing plywood siding
with typical framing and fiberglass batts, I installed 3” iso, building
wrap, 3/4” osb furring strips and plywood siding supported with screws that did
not penetrate the building wrap. My thinking at the time was that it was a
redundant layer block air flow from any flaws in the sealing of the seams.
</FONT></DIV>
<DIV><FONT size=4 face="Times New Roman"></FONT> </DIV>
<DIV><FONT size=4 face="Times New Roman">With new construction designed with
uniform planer surfaces, achieving full seal should be doable. I am able
to order eps foam to be formed to the design dimension, eliminating waste.
With a rain gap of 3/4”-1 1/2” is there a need for the the building wrap to
protect wall from liquid water penetrating the siding. My thought is that
the liquid will drain to weeps at bottom (customized galvanized Z strip
flashing), and liquid that holds onto eps will evaporate as will incidental
vapor the penetrates foam from interior. I am making the rain drain cavity
continuous with attic ventilation for good draft. Therefore, I do not see
the risk to the eps from liquid. Only standing water will damage the
eps. Of course, eps is used for coffee cups that holds liquid, although
likely a higher density than the type I eps I plan to use. </FONT></DIV>
<DIV><FONT size=4 face="Times New Roman"></FONT> </DIV>
<DIV><FONT size=4 face="Times New Roman">I hope you all are still out
there. </FONT></DIV>
<DIV><FONT size=4 face="Times New Roman">Thanks</FONT></DIV>
<DIV><FONT size=4 face="Times New Roman">Eli
</FONT></DIV></DIV></DIV></DIV></DIV></DIV></BODY></HTML>