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Posted by Dan Deckert on December 12, 2006, 1:37 am
I'd really like to see the design/erection/detail drawings for this setup.
I'd also really like to hear if you reach a conclusion for the noise. I've
never heard of a deal like this before. Personally I can only 'suspect'
thermal expansion. On a stupid note, any chance the building itself is
transferring noise from the walls to the roof? As in does the noise start on
one side of the building and transfer across the roof? Radiant
heating/cooling on 1 side 1st?
Dan
> Tom, thanks for the reply, it is the first one we rec'd.
>
> I will post what we ultimately (hopefully) find out to be the cause.
>
> At this point I suppose possibilities may include the need for a
> separation layer (thermal break) or vapor barrier between the metal
> deck and the bottom of the iso; perhaps the iso was installed too
> quickly after manufacture, i.e. foam not fully cured/conditioned; lack
> of separation (gap) between the iso panels; loss of bond between OSB
> and foam; improper or inconsistent fastening of the iso panels to the
> deck; some reason that thermal bridging is occuring down to the metal
> deck proper, etc.
>
> In NJ do you ever install a vapor barrier or separation layer atop the
> metal deck when it is used in a situation where it is left exposed to
> the interior?
>
> After this problem became apparent, time was spent going around to
> other buildings in the area with exposed metal deck, notably the bigger
> box retail structures, and similar noise was heard, to varying degrees,
> although in those installations (much higher ceilings, relatively noisy
> interior simply based on usage) it is not as problematic as for office
> space, where a quieter environment is needed.
>
> In a school (gymnasium, cafeteria, etc.) for example, perhaps the noise
> does exist, but is not as noticeable? If this type of roof cross
> section were ever used in classrooms, or a library, the noise likely
> would be more of an issue.
>
> Dan Wind
> Tom Cular wrote:
> > Any responses you receive will be interesting; we do a lot of this type
> > roofing on schools in NJ (similar climate ), but have not yet heard
noise
> > complaints.
> >
> > Tom
> >
> >
> > > Anyone ever experienced what appears to be much (and loud) thermal
> > > noise from polyiso nail base panels? We are involved in a
> > > recently-completed office bldg in St. Louis. The sloped part of the
> > > roof system is comprised of acoustical `F' deck attached via puddle
> > > welds to open web bar joists, atop which is polyiso nail base (R-30)
> > > and standing seam metal panels. There is an ice and water shield below
> > > the standing seam panels, on top of the nail base OSB. There is,
> > > however, no separation layer or vapor barrier between the metal deck
> > > and the bottom of the polyiso. The building was designed so that the
> > > top floor has a "loft" look, i.e. the roof structure is fully exposed.
> > > The noise sounds like thermal expansion, but is very loud, and
> > > widespread. Seems to be more prevalent in the morning on a sunny day
> > > or, given the current climate in St. Louis, when the heat kicks either
> > > `on' or `off'. Diagnostics to-date have included removing some of the
> > > standing seam metal panels, as it was thought the standing seam metal
> > > was the source of the noise, perhaps the clips were binding. However,
> > > after removing the metal panels the noise still persists and, as the
> > > cold weather has really set in, we also now hear much `popping' on a
> > > flat section of the roof that has solid (non acoustical) metal deck,
> > > topped with polyiso panels and a white colored TPO membrane (no metal
> > > panels). On the sloped portions of the roof, besides "popping" it
> > > sounds almost like a `tarp flopping in the breeze', rolling across the
> > > entire roof, even on calm days with no breeze. This noise (the
> > > "rolling" widespread variety) also existed in the summer when weather
> > > was warm. We are now focusing on the nail base insulation. Tentatively
> > > we are planning to remove some of the nail base panels to see how they
> > > look. The noise is so great the upper floor is untenable for
> > > professional office space. I had thought polyiso was relatively
stable,
> > > inert stuff that should not be subject to thermal expansion. Almost
> > > seems like the polyiso is binding to the metal deck and then releasing
> > > itself. Any advice/history anyone can offer much appreciated.
> > >
>
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