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Re: SIP spec

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I think Premier's ICC report (or equivalent report) has shearwall values for SDC D,E,F.

The aspect ratio of the wall is 1:1 IIRC.... for those zones...


On Fri, Mar 19, 2010 at 12:11 PM, Scott Maxwell <smaxwell(--nospam--at)> wrote:
Ah, SIPs!  Nothing like discussing the dysfunctional world of SIPs.

The first thing you are going to have to do is narrow down what you wan to consider as SIPs for your projects.  I would first assume that we are talking about wood based SIPs (i.e. wood skin - insulation - wood skin).  There are concrete based SIPs as well as metal based SIPs (either might also be called a sandwich panel as Harold mentioned).  Some SIPs will also have drywall skins, but they are usually not truly considered SIPs as they are basically typically non-structural.

Assuming we are talking about wood based SIPs, you next need to decide if you are only interest in EPS based SIPs or if you will also consider XPS and/or foam in place (aka polyurethane) SIPs.  You will find that the "big boys" in the SIP industry will generally be EPS based SIPs with OSB skins.

As far as a sample contract specifications, you can usually find the "big boys" will have a sample specification that you can start with.  Of course, they will be tailored to THEIR product.  Since most of the "big boys" use EPS, such sample specs will only typically be written to permit EPS.  So, if you want XPS or polyurethane, then you will need to add those in.

Here are some samples:

General PBS Roofs, Walls & Floors Specification (PDF) (Premier)

General PBS Roofs, Walls & Floors Specification (Word Document) (Premier)

Insulspan Master Guide Specification (PDF)

Insulspan Master Guide Specification (Word) 

SIP Specification (R-Control in Word format)

There are likely others that might have something.

As to "code reports", the "big boys" (Insulspan, R-Control, & Premier) will all have ICC-ES reports.  Not too many beyond them will.  SIPA has gone about getting a "generic" "code report" that members of SIPA can get listed on, but it is not a ICC-ES report, but rather an NTA report.  You can find information about it here:

All of the "big boys" should now have shearwall values that exceed 335 plf in their ICC-ES reports I believe.  I will note, however, that technically any current ICC-ES report that has been done under the current Acceptance Criteria for SIPs (AC04) will only permit those shearwalls to be used for wind and for Seismic Design Categories A, B, and C.  If you have a Seismic Design Category D, E, or F, then current ICC-ES reports will not apply.  Some of the manufacturer's might have "legacy reports" that supposedly would permit use in high seismic zones, but those older ICC-ES, ICBO, NER, etc reports are not technically valid for the most recent editions of the IBC codes.  So, if your jurisdiction is using more recent IBC code (i.e. 2006 or 2009...and maybe even would have to check what the specific reports are valid for), then you might be SOL for high seismic as far as code report goes.  Most of the "big boys" will have a technical bulletin, however, that reports on some testing that you could potentially use to try to convince a code official to allow for high seismic use., but that will force you to try to convince the code official.

As Gary noted, there is also the prescriptive SIP provisions in the IRC.  It should be noted that they are only for walls made of either 4" or 6" SIPs and of a certain height.  So from a design point of view for engineers, those provisions are kind of useless.  He is correct in that it might help provide some guidance for creating a specification.

The link that Harold linked to is the APA effort to create a SIP standards.  I am a member of that committee, but that committee is kind of "in a coma" at the moment.  The efforts of that committee are basically turning out to be fleshing out the prescriptive provisions from the IRC.  As such, it is debatable how useful that standard would be to engineers if it ever comes to be.  Once again, however, it might be a good source of some "guidance" for a specification.

If you have further questions, feel free to ask...either here on the list or privately.  Since I have been "living" in the messy world of SIPs for the last five years or so, I should be able to help.



On Mar 19, 2010, at 1:45 PM, Harold Sprague wrote:

Good question and very timely!  There are no rules in this knife fight ....yet.  I like SIP's, but it is the wild west right now for standards.  And what can add a lot of complication are things like EIFS and other siding.  We structural engineers need to at least have an awareness of those other things that go bump in the night.  
APA is in the process of developing some standards.  They have a draft standard that is pretty good.  And pretty good now is a whole lot better than perfect in a year.
For your enlightenment:
You should make sure that they have a current ICC ES report.  It is important to note that not all SIP's are the same.  Manufacturers use different insulation, different skins, and different construction.  Aside from the structural issues there are off gassing issues, air quality, water ingress issues, mold, etc.  All the issues can be addressed with good backing from the manufacturer.  Attached is one manufacturer that has done some homework.
I would start off with a search of the ICC ES to determine which manufacturer has done the testing required to get listed.  You have to be careful on the search.  They will come up as sandwich panel, insulated panel, structural panel, etc.  There is no single search that will have all SIP's listed in the ICC ES.  But the ICC ES is a pretty good benchmark, but you have to look at each one to see if it fills all of your needs.  

Regards, Harold Sprague


Subject: SIP spec
Date: Fri, 19 Mar 2010 08:50:07 -0600
From: GordonGoodell(--nospam--at)
To: seaint(--nospam--at)

Has any of you written SIP specs to include in your GSN that youd be willing to share?

Gordon Goodell

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