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Posted by on August 14, 2007, 5:19 pm
> I am repeating a lot of what I have heard from a local home inprovment show
> down in the houston area, but the guy is heard all over the state, google
> Tom Tynan, and see what you can find, but what the barrier does is reflect
> the sun radaiant heat back, it realy dont reflect that much back into the
> attic, just keeps it from getting so hot, we put that bubble type stuff up
> in my folks house, and where it was as compared to where it was not, you can
> feel a difference, best way to figure out where to put it, is too look at
> where the sun hits the house, mostly on the south side, as that tends to
> collect most sunshine.
>
>
>
>
> > > What I know about it, its a spray on, like paint, can be spryed with
> airless
> > > equipment, as to uniform, depends on how well you can spray, like paint,
> > > down here in texas some insulators are also into spraying it, I want to
> say
> > > I have heard that Sherwin Williams stores have the paint, or check with
> the
> > > Florida Solar Energy Center, may can get more info from there.
>
>
> > > > Hi Craig.
>
> > > > I'm not failure with a spray-onradiantbarrier, do you know anything
> > > about
> > > > it?
> > > > Wonder as to how uniform it would be?
>
> > > > > One way I have seen it done is to have theradiantbarriersprayed in
> > > the
> > > > > attic, that is done a lot in retrofit, and seems to work pretty
> well,
> > > the
> > > > > plywood is still the way to go in new const though.- Hide quoted
> text -
>
> > > - Show quoted text -
>
> > All, spray on paints are, by definition of several sources, are "not"
> > radiant barriers. They are actually Interior Radiation Control
> > Coatings (IRCCs). A radiant barrier has to have a minimum of 10%
> > emissivity and 90% or more reflectivity (California Title 24 code is
> > even more stringent). There are several manufacturers of the
> > reflective paints, all with different reflectivities. A foil is a
> > "known quantitiy" by virture that the inherent properties of aluminum
> > foil have a 3% emissivity and 97% reflectivity. Paints are almost
> > always applied by a contractor just because most people do not want to
> > rent a spray applicator , deal with the mixing of the paint, etc.,
> > etc. Whereas, foils can be applied by different methodologies.
> > Another consideration about paints is that if the decking ever has to
> > be replaced due to damage, the paint goes away as well.
>
> > Regarding the San Francisco situation, concur that if you can't find
> > the OSB or plywood decking with the foil already adhered to it, there
> > are foils and other foil products that can used as underlayment.
>
> > I have a list of links to several unbiased, government and university
> > technical sources on my website: www.reflectafoam.com/technical.html.
> > If anybody needs further info or specific information, don't hesitate
> > to contact me.
>
> > Thanks, Donnie.- Hide quoted text -
>
> - Show quoted text -
Craig, unless there is shade on the roof "all day long," one should
consider radiant barrier on all areas of the roof, including attached
garages. The entire goal of the a radiant barrier system (including
ventilation) is to reduce the temperature of the attic so there is not
as much heat the attic insulation has to "resist" ("R"-value) and
thereby migrate into the living spaces of which requires the HVAC unit
to run longer. All roof areas will contribute to heating the attic
even if they face the East and North. Granted, the roof decking
surface temperature may be approximately 10 degrees F lower on a North
or East facing roof (compared to the South and West roof lines), but
when the surface temperature is 120+ degreees, those roof areas will
still be cooking the attic.
Thanks, Donnie.
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