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<div class="moz-cite-prefix"><font face="Helvetica, Arial,
sans-serif">There are some really poor quality screws out there,
but I also think there are more high quality, specialized,
designed for powerful electric drivers than ever before. Torx
heads and hex heads improve beyond the already decent
performance of square drive Robertson screws.<br>
I spent the weekend doing some carpentry, building stabling in a
barn. Half the fasteners I used were screws, #9 and #10 1.5"
long and #10 2.5" long. Hex head drive, and corrosion
protected. Never stripped a single one, and mostly used a
DeWalt 18V impact driver. Half of these screws were being driven
to 1.25" into white oak rough sawn 6x6 or 2x8-- really quite
hard dense wood. The only screws that twisted off were the ones
I installed several weeks ago into the oak,</font> and I tried
to remove them, resulting in the shaft snapping off in about 3
cases of 10 or 12 removals. I chose to buy "good" screws for
this: Simpson Strong Tie SDS screws because my previous experience
suggested they work well. Not disappointed but I did pay between
8 and 10 cents each for them.<br>
I also installed a ton of #10 2.5" green deck screws with a square
drive. These screws will routinely twist off with dense lumber,
and will also spin out unless you applly perfectly. But they are
really cheap, and for attaching to soft SPF or SYP lumber, they
are fine.<br>
So, I guess, I see this as a shopping exercise. Get the right
stuff.<br>
My point on the screws for foam was that they need to be different
screws than the good structural ones.<br>
The Fastenmaster line of HeadLok and OLG etc screws are fantastic:
strong, easy to apply, etc. But too expensive for all purposes
other than the most demanding.<br>
<br>
Can you use nails? yes, but for any commercial work (not DIY)
nails cost too much labour. You would need to use ring shank
nails to get decent pullout, and it is hard to find nails over 4"
that are small enough diameter. Standard nails with 1.5"
embeddment in stud will work great, but at insulation thickness of
3" or so and higher, they get way too big.<br>
The NYSERDA testing (results summarized in the report on our
website) showed that nails worked well for thinner layers of foam.<br>
<br>
PS. Because of my choice to experiment on my own retrofit, we
installed gutter spikes through the long direction of pre-drilled
2x3's, and held the 2x3 off the wall 2" to allow spray foam to
cover the existing wall and embed the 2x3. The nail in this
application was needed only for initial installation: the ccSPF
does all the work after.<br>
<br>
<br>
<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 12-11-18 7:27 PM, Tim Brown wrote:<br>
</div>
<blockquote
cite="mid:5B101900-0AC1-4D67-B6DB-27D9524AA6C6@optonline.net"
type="cite">Just an observation…..
<div>Building with screws these days is hit and miss.</div>
<div>Quality of fasteners are atrocious or perhaps
screws were never designed to be </div>
<div>installed with high torque/ high speed drills.</div>
<div>Over the years I have seen so many times where
screws fail because of</div>
<div> the structural compromise that results from
the actual driving of the screw with a drill.</div>
<div>Heads snap off and / or they strip.</div>
<div>Stripping is mostly due to improper used of screw gun
me thinks. To fast , wrong orientation of drill and not
enough pressure……</div>
<div>Cost of these things just keep going up.</div>
<div>Would it be possible to use hand hammed nails?
Not a nail gun.</div>
<div>I think old school might be cheaper and more
reliable if slow.</div>
<div> </div>
<div><br>
<div>
<div>On Nov 18, 2012, at 7:14 PM, Eli Talking wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
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<div><font size="4">This issue is of interest to
me. </font></div>
<div> </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> </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> </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> </div>
<div><font size="4">Eli </font></div>
<div> </div>
<div> </div>
<div> </div>
<div> </div>
<div>
<div style="FONT: 10pt tahoma">
<div style="BACKGROUND: #f5f5f5">
<div style="font-color: black"><b>From:</b>
<a moz-do-not-send="true"
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 moz-do-not-send="true"
title="terrain@shaw.ca"
href="mailto:terrain@shaw.ca">John
Salmen</a> </div>
<div><b>Cc:</b> <a moz-do-not-send="true"
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 moz-do-not-send="true"
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 moz-do-not-send="true"
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 moz-do-not-send="true" 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 moz-do-not-send="true" 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 <a moz-do-not-send="true" href="http://buildingscience.com">buildingscience.com</a> 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 moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:colsen@fairpoint.net">mailto:colsen@fairpoint.net</a>
Sender: "Greenbuilding"
<a moz-do-not-send="true" 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 moz-do-not-send="true" class="moz-txt-link-rfc2396E" href="mailto:greenbuilding@lists.bioenergylists.org">mailto:greenbuilding@lists.bioenergylists.org</a>
Reply-To: Green Building <a moz-do-not-send="true" 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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</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 moz-do-not-send="true" 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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