Re: structurally integrated panels
From: John Faust (
Date: Fri, 1 Feb 2008 16:38:30 -0800 (PST)

Late or not, I appreciate the details. So far most everything has been
encouraging. I have two questions:

   1. Do I understand correctly when you say it was the contractor's
   problem in installing the upstairs decks and not the architects design? The
   design wasn't difficult to implement?

   2. Given the sound transmission characteristics of SIPs, was it simply
   a matter of dollars that dictated the use of standard (albeit offset) stick
   walls for the walls separating units? Or, do I overestimate their ability to
   attenuate sound?

Thanks again.

John Faust

On Feb 1, 2008 5:18 PM, Kay Argyle <kay.argyle [at]> wrote:

> Sorry for a late response. This got lost in my "drafts" folder ...
> > Have any communities used or are any communities planning to use SIPs in
> > their structures. It would seem to have many advantages (well insulated,
> > rapid construction, precision and accuracy, sound attenuation) and at
> least
> > one disadvantage (formaldehyde emissions).
> Wasatch Commons (SLC, Utah) was built using R-Control brand structurally
> insulated panels (SIPs), cut to the architect's specifications at the
> factory, trucked to our location, and assembled.  They consist of a 6"(?)
> foam core, like fine-grained styrofoam, sandwiched between strandboard.
> Apparently the foam contains boron for pest control - you really do not
> want
> to handle broken pieces and then touch your eyes (as I found out the hard
> way).  I didn't notice any offgassing smells from the panels, even during
> construction.
> We have natural stucco outside the SIPs.  Interior walls are stud
> construction, with offset studs and batting between attached townhouses.
> Insulation is excellent. During the summer our downstairs is typically
> about
> 15 degrees cooler than outside.  We have a lot of windows, so any
> advantage
> in sound attenuation isn't that noticeable.
> I do recommend offset studs! We can occasionally hear the neighbors' music
> or washing machine, but only faintly - a vast improvement over the usual
> attached unit. I wish the architect had had the sense to use offset studs
> or
> other soundproofing for walls within the units as well - as one resident
> put
> it, if she sneezed in the kitchen, her husband said gesundheit from the
> bedroom, on the opposite end of the unit.
> SIPs are more stable in earthquakes than stud construction (theoretically;
> I
> hope not to be a test case) - a consideration in an area that has averaged
> a
> magnitude 7 or higher approximately every 350 years for the last several
> thousand (currently 250 years overdue :O).  On the other hand, our
> location
> in the valley puts us in more danger from soil liquefaction or a seche
> wave
> than from shaking.
> The time benefits of SIP construction are greatest for long straight
> stretches of wall, dropping 8x24-ft panels into place one after another.
> Oops - Our architect liked corners. The exterior walls zigzag in and out,
> and most are shorter than 24'.
> The electrician's opinion of SIP construction was profane.  The foam has
> open channels about two inches in diameter, horizontally at knee and chest
> height, and vertically every six feet or so, for wires. Many places he had
> to run multiple wires, and had a major struggle them all through that
> narrow
> tube.  Pipes and ducts had to go through interior (stud) walls - except
> downstairs has an floorplan, meaning every pipe, wire, duct, and cable for
> the upstairs had to be fed through a single three-foot-long wall.
> A serious shortcoming is strandboard's behavior when wet.  An error in
> construction of the upstairs decks on half a dozen units resulted in water
> running down inside the stucco.  We kept finding little crumbs on the
> floor
> near a gap in the baseboards. Finally my roommate pulled off the drywall
> to
> see what was going on (she was thinking insect infestation).  The
> strandboard had rotted out, leaving only the foam to support the weight
> above. Fortunately that was not a major load-bearing wall. Despite it
> being
> well past the one-year warrantee on the construction, the architectural
> firm
> and the contractor chose to take responsibility - thank heavens, otherwise
> the community would have faced at least tens, possibly hundreds, of
> thousands in repair costs, as it entailed ripping out and replacing entire
> exterior walls.
> Kay
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