[Greenbuilding] [BULK] Re: metal roof sheathing, fastening, and noise

[Lawrence Lile]

My roof was installed over 30# felt paper as well (sorry, the contractor did it, so I can't recommend any guides). 
 
Having lived there for a while, I know that the roof condenses mightily.  I have a downspout next to my bedroom, and every time there is a clear night, it sounds like rain all night!  THat's just heavy dew condensing ont he metal roof.  almost all of the dew will eventually drip off, and thus I hear it.  It is most prevalent on clear summer nights, because objects exposed to clear sky cool off below the dewpoint more readily.  I would suppose some of that could be condensing under the roof, if there is much airflow under there.  That would make me argue for no airspace under the roof, just 30# felt. 
 
--Lawrence Lile

________________________________

From: greenbuilding-bounces at listserv.repp.org on behalf of Thomas Lewis
Sent: Sat 8/25/2007 4:29 PM
To: Sacie Lambertson; greenbuilding at listserv.repp.org
Subject: [BULK] Re: [Greenbuilding] metal roof sheathing, fastening, and noise



So the red paper, red rosin paper?, or the perlins
precluded a condensation problem? 
I would think that the perlins may allow for air to
come and go and allow drying, but wouldn't there still
be condesation under the metal?

Best
Tom

--- Sacie Lambertson <sacie.lambertson at gmail.com>
wrote:

> At 05:37 AM 8/25/2007, Thomas Lewis wrote:
> >I have been thinking of replacing my aged asphalt
> roof
> >with metal, I want to put the metal up on perlins
> so I
> >can shim the roof out to a flat plane, but I want
> to
> >allow condensation to drain.
>
>
> Back in Virginia 20+ years ago where experienced
> standing seam
> roofers installed one over our asphalt single
> sheathed roof, they put
> down 'red' paper immediately under the metal roof
> (as I recall)--we
> put purlins immediately on top of the shingles.  My
> understanding of
> this procedure was that it precluded a condensation
> problem.   Around
> here 30# felt is used under metal roofs, both
> standing seam and the
> commercial type. Sacie
>
>
>


"Time makes more converts than reason."  Thomas Paine, Common Sense


      
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