[Greenbuilding] Insulation fasteners

[John Salmen]

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 [mailto:greenbuilding-bounces at lists.bioenergylists.org]
On Behalf Of George J. Nesbitt
Sent: November-14-12 6:57 PM
To: jfstraube at gmail.com; 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:
> We have tested up to 8" of foam (EPS, XPS is stronger) with #10 screws and
furring strips. Works fine with siding ( safety factor of more than 10).
> 3/8" lags is crazy: never need it. The foam provides a lot of the
strength.
> Check our buildingscience.com website or my book for more detail on how
this works.
>
> Sent wirelessly from my BlackBerry device on the Bell network.
>
> -----Original Message-----
> From: Clarke Olsen <colsen at fairpoint.net>
> Sender: "Greenbuilding" 
> <greenbuilding-bounces at lists.bioenergylists.org>
> Date: Wed, 14 Nov 2012 09:50:23
> To: Green Building<greenbuilding at lists.bioenergylists.org>
> Reply-To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Insulation fasteners
>
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--
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, www.houseisasystem.com, (510)
655-8532 office, (510) 599-5708 mobile

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