On Aug 9, 5:41 pm, "Dennis" wrote:
One of the major problems with any radiant system is that the dust that
forms on its surface will degrade it reflectivity. One of the biggest
problems with radiant barriers. Oak Ridge has a good deal of info on this,
one doc I see referenced from your website "Radiation Control Fact Sheet"
found on the Oak Ridge website. It discusses how these barriers defrade over
time. Even so, people who live in the sun belt, Arizona and the like, would
benefit greatly from adding a radiant control barrier to their homes.

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 -

Dennis, you are correct but studies, especially by FSEC show that dust
collection and the resulting radiant barrier degradation is when a
foil is placed on top of attic floor insulation. System deterioration
is nil or minimal when the foil is placed on the bottom of the
rafters, between the rafters or next to the roof decking.

Thanks, Donnie.