On Aug 11, 5:34 am, "Craig M" wrote:
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.
Hope this wrote in message

oups.com...



On Jul 31, 5:53 am, "Craig M" wrote:
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.
Hope this helps"Dennis" wrote in message

news:V5uri.3010$6f4.61@trndny01...

Hi Craig.

I'm not failure with a spray-onradiantbarrier, do you know anything
about
it?
Wonder as to how uniform it would be?

M" wrote in message
.net...
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.