Sounds like good info. Thanks Bob-tx


"neutralexistence" wrote in
message m...
neutralexistence had written this in response to
http://www.thestuccocompany.com/main...rs-378805-.htm
:

Bob-tx wrote:


I have been reading about everything I can find on radiant
barriers,
but still have a few questions and concerns.

I am not talking new construction here, where radiant barrier can
be
installed under the roof sheeting. I am talking about existing
homes, and then, primarily the spray on type.

Here is what I think I understand - -

Sprayed on radiant barrier will cut down 65 to 75 percent of the
sun's radiation, - but I really don't know how much cooler that
makes the attic.

Sprayed on radiant barrier effectiveness depends primarily on the
people who do the work. They can thin out the paint so it is
much
less effective, they can spray it on to thin as well, and not get
the complete underside of the roof. Most homeowners would never
know they didn't get a good job. This is a major concern.

Dust on a radiant barrier surface decreases its effectiveness -
the
more dust, the less effective. Although there generally is not a
lot of dust floating around in most attics, it can be stirred up
easily. For example, adding more insulation is a dusty
procedure,
and if there is a previously installed radiant barrier, you will
decrease its effectiveness - to some varying extent.

There is a company that advertises radiant barriers for half
price
(whatever that is) and free added insulation. If they spray
their
cheap radiant barrier (about which I would have concern about how
it
was mixed/thinned) and then add the insulation - instant dust.

This company has been advertising for months with some fantastic
deal or other and will only quote prices through an in home
salesman. I smell high pressure here.

Has anyone used this company? Has anyone used other companies
to
spray a radiant barrier, and how satisfied are you?

I know I am asking a lot of questions, but I sure don't relish
the
idea of getting ripped off. Thanks,

Bob-tx


Hey Bob,

Let me see if I can shed some light on the questions. First of all
the
paint type radiant barriers(term used loosely) have a
"reflectivity" of no
more than 75% which "technically" is not, by definition, a radiant
barrier. A radiant barrier, technically defined, will have a
reflectivity
of at least 95%.

I highly recommend a foil sheet type a
href="http://www.raflect.com"radiant barrier/a with a
reflectivity
value of 97% to 98%. While the installation is a bit more
challenging, the
results will be much better.

To address you question about dust and radiant barriers. While it
is true
that dust can degrade the effectiveness of a radiant barrier, by
purchasing a double sided radiant barrier, you eliminate this
problem.
Also, even if you do have some dust on the single sided radiant
barrier,
it is still more effective then the paint type radiant barriers.

As far as installation, I highly recommend stapling the radiant
barrier to
the bottom of your roof rafters. This will leave a gap (usually
5-1/2")
for air to move from your soffit vents up to your ridge vent,
effectively
moving the hot reflected air up and out of your attic causing your
whole
attic to be cooler.

Cooler attic means lower strain on your HVAC system causing lower
energy
bills.

I also recommend getting a perforated type radiant barrier so you
do not
run the risk of any condensation issues which could lead to
structure rot
and/or mold.

Anyway, if you have any other questions let me know.

Adam

-------------------------------------
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http://www.neutralexistence.com



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