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<DIV><FONT size=4>This issue is of interest to me. </FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>I installed 3/4”x3” osb furring strip over 3” iso boards over
existing plywood siding. I had Z shaped metal flashing installed at the
bottom that provided rodent protection and temporary support for the foam during
assembly. The foam joints were sealed with acoustic caulk.
</FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>I did have trouble with using <FONT face=Verdana><FONT
style="FONT-SIZE: 9pt" color=#b22222>10 X 6 Drywall Screws / Fine / Phillips
<FONT face="Times New Roman"><FONT style="FONT-SIZE: 13.6pt" color=#000000>on
the first part of the project which was installing 3”iso boards below a
cathedral ceiling. Perhaps the problem was the fine threads that maybe are
intended for sheet metal. However, we had difficulty getting them to
penetrate the wood and maintain the Phillips head without stripping.
Suggested by this list, I learned about the bugle head GKR fasteners. I
absolutely love these fasteners. They always penetrate and very seldom
strip. I would like to test some alternatives. However, since they have to
be ordered in bulk, this is hard to do. Maybe the thicker thread sheetrock
screw would work. However, John Straub, I am hearing you about the cost of the
structural fasteners. Can you identify the screws you like?
</FONT></FONT></FONT></FONT></FONT></DIV>
<DIV> </DIV>
<DIV><FONT size=4>However, on the exterior, I was less conservative on the
spacing, 4 per 8’ vertical. I analyze it like this. For the paneling
mounted on furring strips to sag, they must rotate with fulcrum at plane where
screw enters the wood below foam. In order to do this, they must compress
the foam horizontally. Like a footing, the weight of the structure
should be divided by area furring strip to determine if within compressive
strength of foam which is specified by manufacturer. </FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>I am moving forward on a new project where I want all the
insulation to be achieved with the exterior mounted eps foam. I found a
source of eps that is as low a price as fiberglass/sf R. Therefore, I do
not want to ues the framing as the thermal barrier. Since it is new
construction, I can support most of the foam vertically be setting on the
termite-rodent shield-flashing setting on the foundation. I am considering
using a 2x3 for furring of the drain-dry plain to give real wood for mounting
finishes. Perhaps this thicker furring strip will allow me to use fewer
expensive structural fasteners. Because of the long screws this will
require, I was looking at the possibility of accurately pre-drilling pilot holes
with drill press in a shop such that if accurately located furring on house, the
screw will maintain a perfect perpendicular axis and find the stud. I did
have the issue this issue of finding the rafters on my ceiling mounted hand
drilled installations. On exterior mounted insulation, I had original 3/4”
plywood that gave plenty of grip where ever I drilled. </FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4>Eli </FONT></DIV>
<DIV><FONT size=4></FONT> </DIV>
<DIV><FONT size=4></FONT> </DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=jfstraube@gmail.com
href="mailto:jfstraube@gmail.com">John Straube</A> </DIV>
<DIV><B>Sent:</B> Thursday, November 15, 2012 9:36 AM</DIV>
<DIV><B>To:</B> <A title=terrain@shaw.ca href="mailto:terrain@shaw.ca">John
Salmen</A> </DIV>
<DIV><B>Cc:</B> <A title=greenbuilding@lists.bioenergylists.org
href="mailto:greenbuilding@lists.bioenergylists.org">'Green Building'</A> </DIV>
<DIV><B>Subject:</B> Re: [Greenbuilding] Insulation fasteners</DIV></DIV></DIV>
<DIV> </DIV></DIV>
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<DIV class=moz-cite-prefix><FONT
face="Helvetica, Arial,
sans-serif">John, much of what you say
is not correct. This bothers me because I routinely hear these false claims
made, and this incorrect information impedes progress in making good energy
efficient buildings (something I know you care about).<BR><B>You can get long
screws that are not "structural screws".</B> I know, because we and many
others installing thick layers of foam insulation and have been doing this for
years. There must be a few dozen case studies alone on our website.<BR>Yes, long
structural screws are what you find at Home Depot, but these expensive and
problematic in a number of ways.<BR><FONT style="BACKGROUND-COLOR: #ffff00">It
is quite possible to get #10 or #12 screws in lengths of 6" and up. #10 is
typically only available to about 6" length, and then #12 to about 12 or 14"
long, and then you are up to #14 / 1/4" dia for lengths up to 20" or so. We
regularily find that a #12x6" can be cheaper than a #10x6" and thus use them,
but #10 is what we have always tested in the lab because they are the smallest
available and hence the most flexible with the lowest pullout loads. Their
heads DO NOT torque off when used to attach foam. They are NOT
intended for screwing through solid wood but through insulation, which is why
they work perfectly well. </FONT></FONT><FONT
face="Helvetica, Arial, sans-serif"><FONT
style="BACKGROUND-COLOR: #ffff00"><FONT
face="Helvetica, Arial, sans-serif">Millions of 6" long or longer screws are
installed every year through foam in the commercial low-slope roofing and EIFS
industry (see for example Wind-lok for #10x6" long). This is the first
stop if you are looking for long thin screws that have corrosion resistance, are
easy to install and affordable. These products in these building
niches all have a long track record of being installed by the thousands
without problems of torquing off heads, driver slippage, bending, or whatever
other excuses I have heard. </FONT>They have been designed for embedding about 1
to 1.5" in wood after screwing through 4-12" of roof or EIFS
insulation.</FONT> What is not easy for individuals and small contractors is
finding these screws because they are typically carried by larger supply houses
and commercial sales outlets. If more people start super insulating their
houses, I am pretty sure the fastener industry will respond by marketing their
roof screws as wall screws and the problem will go away.<BR><BR>The HeadLok
screws are great for many structural applications, but I think these are used
for attaching foam and furring only because they are available at retail
outlets. There are quite nice, but are usually twice as expensive as the
alternatives (40 cents each and up), and often three times the cost retail (eg
we get supply house prices of 12 cents on a #10x6" and the contractor tells us
that HeadLok or GRK cost $150 for a 250 pack). <BR><BR><B>The screws are
also NOT the most expensive part of the assembly.</B> Not even
close.<BR>If you purchase relatively heavy 6" long screws from, say, here <BR><A
class=moz-txt-link-freetext
href="http://www.bestmaterials.com/detail.aspx?ID=9221">http://www.bestmaterials.com/detail.aspx?ID=9221</A><BR>They
cost maybe 20 cents each (these are #12-14 screws) Not the cheapest
source but not bad. Often available for 15 cents. If you use one
screw every 12" vertically and 24" horizontally (pretty conservative), that is 1
screw per 2 square feet or about 10 cents/square foot at 20 cents each.
When labour is added, the screw might be 3 times as expensive (30 cents /square
foot).<BR>4" of polyiso will cost something in the order of $2 to $2.50 per
square foot, making the screw less than 5% of the cost of materials for the
exterior insulation (adding the cost of furring strips changes little). 4" of
EPS will be about $1.50. With labour, the screw is still around 10% or
less.<BR><BR><BR></FONT>
<DIV class=moz-signature>Dr John Straube, P.Eng. <BR><A
class=moz-txt-link-abbreviated
href="http://www.BuildingScience.com">www.BuildingScience.com</A></DIV>On
12-11-14 11:10 PM, John Salmen wrote:<BR></DIV>
<BLOCKQUOTE cite=mid:02c701cdc2e7$344df2d0$9ce9d870$@ca type="cite"><PRE wrap="">When you get into long screws they are structural screws - equivalent to a
3/8" bolt (actually better). For sure they are overkill but that is where
eng. crosses practicality. When you increase length on anything the design
requirements for actually getting the screw into the material override the
design criteria for loading. The reason being that you cannot screw a long
softmetal screw into an assembly without torqueing off the head. - I don't
even think you can even find a #10 standard soft metal screw in long lengths
anymore - I remember putting an order in from one manuf. a decade ago and
half the screws were thrown away from having heads torqued off. 1/4" and
3/8" lag bolts would also self destruct far too often in application to make
them practical for a load that an 1/8" of metal would carry. We are talking
about crews that have to install a lot of bolts/screws in a day and wasting
their time with defective material is an overriding consideration.
Headlok screws that I mentioned will cost about .30 per for 6" and about .50
per for 8" and each screw will do what is supposed to do. They drive in
quickly and perfectly each time. They have a large wafer head equivalent to
a washer so one screw generally takes the place of at least 2 screws in
design.
Fastening is the overriding cost in assemblies at this point and it is split
between the cost of the fastener and the time taken to fasten. That is why
most buildings are being put together with adhesives.
-----Original Message-----
From: Greenbuilding [<A class=moz-txt-link-freetext href="mailto:greenbuilding-bounces@lists.bioenergylists.org">mailto:greenbuilding-bounces@lists.bioenergylists.org</A>]
On Behalf Of George J. Nesbitt
Sent: November-14-12 6:57 PM
To: <A class=moz-txt-link-abbreviated href="mailto:jfstraube@gmail.com">jfstraube@gmail.com</A>; Green Building
Subject: Re: [Greenbuilding] Insulation fasteners
I'm about to screw through 4-1/2" of polyiso, I can only find 6" screws
affordably ($13/100ea), longer screws are $1ea. Sources & prices for 6"+
#10 screws?
On 11/14/2012 7:53 AM, John Straube wrote:
</PRE>
<BLOCKQUOTE type="cite"><PRE wrap="">We have tested up to 8" of foam (EPS, XPS is stronger) with #10 screws and
</PRE></BLOCKQUOTE><PRE wrap="">furring strips. Works fine with siding ( safety factor of more than 10).
</PRE>
<BLOCKQUOTE type="cite"><PRE wrap="">3/8" lags is crazy: never need it. The foam provides a lot of the
</PRE></BLOCKQUOTE><PRE wrap="">strength.
</PRE>
<BLOCKQUOTE type="cite"><PRE wrap="">Check our buildingscience.com website or my book for more detail on how
</PRE></BLOCKQUOTE><PRE wrap="">this works.
</PRE>
<BLOCKQUOTE type="cite"><PRE wrap="">Sent wirelessly from my BlackBerry device on the Bell network.
-----Original Message-----
From: Clarke Olsen <A class=moz-txt-link-rfc2396E href="mailto:colsen@fairpoint.net">mailto:colsen@fairpoint.net</A>
Sender: "Greenbuilding"
<A class=moz-txt-link-rfc2396E href="mailto:greenbuilding-bounces@lists.bioenergylists.org">mailto:greenbuilding-bounces@lists.bioenergylists.org</A>
Date: Wed, 14 Nov 2012 09:50:23
To: Green Building<A class=moz-txt-link-rfc2396E href="mailto:greenbuilding@lists.bioenergylists.org">mailto:greenbuilding@lists.bioenergylists.org</A>
Reply-To: Green Building <A class=moz-txt-link-rfc2396E href="mailto:greenbuilding@lists.bioenergylists.org">mailto:greenbuilding@lists.bioenergylists.org</A>
Subject: Re: [Greenbuilding] Insulation fasteners
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</PRE></BLOCKQUOTE><PRE wrap="">--
George J. Nesbitt, Environmental Design / Build, Building Performance
Contractor HERS I Verifier & HERS II Rater, GreenPoint Rater new & existing
SF & MF, CABEC CEPE (Certified Energy Plans Examiner), Certified Passive
House Consultant, BPI Multifamily Analyst, <A class=moz-txt-link-abbreviated href="http://www.houseisasystem.com">www.houseisasystem.com</A>, (510)
655-8532 office, (510) 599-5708 mobile
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