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Do
I have to install your radiant barrier shiny side up?
No. Radiant Barriers work
by reflecting infra-red energy which is not visible light. Most products
have one shiny side and one dull side. This finish look is created
in rolling mills, when they make the aluminum sheeting. Both sides
could be dull and they would work the same.
Will
the radiant barrier work if I use it in place of the felt, when I replace
my roof ?
No.
All Radiant Barriers must face an airspace on one side to work.
That space can be as small as 3/4" but, it is the foil surface AND the
air space it faces that together become the barrier. If
you used barrier material in place of felt you would have two problems:
First, if the metallic barrier material is in direct contact with the roofing material
on one side and the roof sheathing on the other, it will act as a conductor
for heat rather than a barrier.
Second, the local building dept. might be unhappy
with you for using a product that is not approved for that installation.
Being approved as a good vapor retarder, as all our RB products are (unperforated),
doesn't qualify them as underlayments.
Can
I install your products directly under my roof sheeting ?
Yes, but only the two products that are offered perforated. The foil
side, of the Aluma-Foil HD product must, face the airspace below.
The perforations in this type of installation are necessary to prevent
the trapping of moisture in the roof that may pre-exist in the OSB or
plywood sheathing. This is a very popular method of installation in
either new construction or re-roofing of an existing structure.
Do not forget to install RB on the gable ends and knee walls when installing
in this method.
How
important is venting in my attic ?
Very. The primary
reason attics are vented to begin with is to remove moisture that
moves into your attic from your home below. Without venting, damage
could develop in the form of mildew and dry-rot over the years and be
both unhealthful, as well as very expensive to repair. A good rule to
remember is to allow one square foot of ventilation for every 150 square
feet of roof area. Good venting will improve the performance of your
radiant barrier and insulation.
How
do I know which radiant barrier is best for what I want to do?
First of all, all
radiant barriers perform the same, as long as their emittance is the
same. It doesn't matter whether they have a paper core material, a bubble,
mylar or any other substrate. They all do the same thing. It is
a matter of cost, handling and how the manufacturer warrants their product.
Don't be afraid to ask a manufacturer for a specification sheet and
sample of the product your choosing. All attic radiant barriers must
have a Class "A" flame spread rating and if they are to be used as a
vapor retarder also they must have a rating of 1.0 perm or less. All
aluminum foil sheeting has an emittance of .02 to .05 and a reflectance
of 98-95%.
Are
moisture and dust a problem if I lay a radiant barrier on top of my
existing attic insulation ?
Moisture should
not be a problem as long as you use the Super Plus perforated product.
This should adequately remove the moisture moving from your home below
into the attic above. The dust issue is simple. If you live in an area
that is windy, and dusty, you will have a problem. Dust is very conductive
and will reduce the reflectance over time. However, if you don't
have this problem , and it takes years to accumulate any dust, don't
worry about it. The reduction in the amount of reflection would take
many, many years and your comfort and savings starts the day you install
your RB. This is the best method of installation in areas where winter
savings are critical.
If
I have ducts in my attic, above my insulation, should I cover them with
RB ?
Absolutely, the
average duct, if it is insulated at all, will only have an R-3 to R-5
insulation wrapped around it. That is considerably less than the insulation
below it! And, its closer to the source of heat gain in the summer.
Who knows why anyone would built like that! RB will greatly improve
your energy savings when you wrap the ducts. However, if the ducts are
already wrapped in foil, even if they only have an R-3 or R-5, you don't
need to wrap them again.
What
other uses are there for your radiant barriers ?
Many. You can put
it on the back of your garage doors to knock down the heat. Its excellent
for wrapping water heaters, pipes, lining crawl spaces, ferring pens,
pole barns, tool sheds, airplane hangars and many other applications.
It can also be used in walls and floors, as long as a minimum airspace
of 3/4" is allowed between the building material and the foil surface.
Anytime you want to prevent heat gain, or heat loss, you probably should
consider using a radiant barrier.
What
about using "foil chips" in my attic ? Wouldn't that be just as good
as laying down your product on my existing insulation ?
No. Some
manufacturers claim their product performs better than other RB products
and that they are not subjected to such problems as dust on the surface, affecting
its performance. When in doubt, you
need to demand that the seller provide you with acceptable test data
on their product. Compare and don't be taken in by false claims.
For example, all RB products installed in attics must have a flame spread
rating of 25 or less according to UBC(Uniform Building Code). That means
the supplier must be able to provide you with a copy of this test if
you request it. When in doubt, ask them to supply documentation!
Those companies who sell radiant barriers in the state of California
must also be approved, and listed, by the State of California, Bureau of Home
Furnishings.
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