<div dir="ltr">It depends on how tight you actually are. If you are tight, foam won't add tightness. If you are not, it depends on the height of your building envelope and how much positive pressure there is at the ceiling to drive exfiltration on a cold night. Loose pack cellulose won't provide any reduction for pressure driven exfiltration. ... Norbert<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Jul 6, 2018 at 12:26 PM, Lynelle Hamilton <span dir="ltr"><<a href="mailto:lynelle@lahamilton.com" target="_blank">lynelle@lahamilton.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">Thanks, Jeff. I've never used open cell foam or indeed any foam in an attic space, so had no idea it was advantageous at all.<br><br><div class="gmail_quote">On July 6, 2018 11:45:10 AM EDT, Jeff Martin <<a href="mailto:jeff@open2learn.ca" target="_blank">jeff@open2learn.ca</a>> wrote:<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div dir="auto">Lynelle, <br><br></div>
<div dir="auto">From your description, the area is already well air sealed and 16 inches or so of cellulose should provide fairly good resistance to air infiltration where there are small leaks. I don't see any advantage to using foam, especially at twice the price. <br><br></div>
<div dir="auto">Jeff <br><br></div>
<div dir="auto">Sent from <a href="http://www.bluemail.me/r?b=13187" target="_blank">BlueMail</a> </div>
<div class="gmail_quote">On Jul 6, 2018, at 9:03 AM, "Lynelle A. Hamilton" <<a href="mailto:lynelle@lahamilton.com" target="_blank">lynelle@lahamilton.com</a>> wrote:<blockquote class="gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<p><font size="+1"><font face="Gill Sans MT">Hi All,</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">Again, I ask this group
for advice! Am insulating an attic space. It's 720 sq feet.
The roof is a north facing slope and gets a lot of wind all
year, including winter. There is a 48 ft ridge vent and hand-built
vents. Location is Greater Toronto area, so definitely a
heating climate.<br>
</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">We've installed vapour
barrier, in anticipation of using blown in cellulose to attain
R60. We've been careful to seal all openings, including the
area around the access hatch and there are no pot lights. The
one duct that runs in the attic (bathroom vent fan) is
insulated. <br>
</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">I've had two
contractors (both in the field for some time) suggest using
open cell (1/2 pound) foam, as it will fully seal the attic
area and allow less heat, condensation, etc. At R60, it's
about twice the price of cellulose, though.<br>
</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">I've no concern about
the ability of either contractor to appropriately install.<br>
</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">I've pored through all
of John Salmen's videos and articles that I can access about
best approach in this setting but confess that I'm no less perplexed.
<br>
</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">Any thoughts, folks?</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">Thanks in advance!</font></font></p>
<p><font size="+1"><font face="Gill Sans MT">Lynelle</font></font><br>
</p>
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