Where & How to Install Radiant Barrier & Reflective Insulation

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RadiantGUARD® radiant barrier insulation products are useful in a wide variety of locations within residential, commercial, and agricultural building structures.

R-Values indicated below vary per installation method depending on the size of the air space surrounding the product and the direction of heat flow.  Because of these variables, you can achieve several different R-Values with one basic product.

Page Index - Jump To Topics

Attics Siding Roofs Walls Floors Crawl spaces Basement / Masonry walls Hot water heaters Garage doors

Metal Building walls & roofs Post Frame / Pole Barn walls & roofs

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Radiant Barrier Applications

Attic Installations

Most of the heat entering a home comes through the roof.  RadiantGUARD® radiant barrier insulation installed in an attics can reduce attic temperatures by up to 30 degrees when installed to the underside of roof rafters by REFLECTING 95-97% of the radiant heat that strikes its surface thereby reducing heat transfer from the attic to living spaces resulting in lower utility bills.  This method also reduces the heat subject to attic mounted AC duct work thereby allowing them to work more efficiently.

A secondary method of installation Instead of installing under the attic rafters, is to lay them over the attic floor.  Although this method of laying over the attic floor wont lower the temperature of your attic space, it will still REFLECT 95-97% of the radiant heat that strikes its surface thereby reducing heat transfer from the attic to living spaces resulting in lower utility bills.  To compensate for the exposed AC duct work with this installation method, you can easily lay a blanket of radiant barrier over the duct work to protect them from the heat.

Installation Instructions:

• Under Roof Rafters in Attic
• Under Roof Decking on top of Roof Rafters
• Over Existing Insulation on Attic Decking
  • *Note: This installation method is not recommended per the Department of Energy Radiant Barrier Attic Fact Sheet for the following reasons.
    • Dust accumulation may diminish the effectiveness over time but not nearly as much as would be expected from the increases in emissivity caused by the dust.
    • May introduce rare occurrences of condensation in colder climates.
• Cathedral Ceilings

Siding Applications

Radiant barriers can be extremely effective at lowering radiant heat transfers when used in exterior siding applications but again, it MUST have an air space on at least one side of the radiant barrier for it to work.  In this application, a radiant barrier is installed like a typical house wrap yet before the siding is installed, you must attach 1 X 2 furring strips over the top of the radiant barrier to which to attach the siding.  This creates the required air space for the radiant barrier to be effective.

 

We recommend our Xtreme perforated radiant barrier for siding applications.

Installation Instructions:

• House Wrap Behind Brick or Aluminum/Vinyl Siding
  • Behind Brick
  • Behind Aluminum/Vinyl Siding

Roofing Applications

A radiant barrier can be very effective at BLOCKING radiant heat when installed in conjunction with roofing and siding material, however, the radiant barrier MUST be installed with an air space on at least one side of it.  As long as there is at least a 3/4" air space on either side of the radiant barrier, the application will be effective at BLOCKING radiant heat.  For more information on why a radiant barrier must have an air space on one side of it to be effective, please see our Radiant Barriers 101 page.

Roofing systems that utilize purlins or batten/counter battens are ideal for the addition of a radiant barrier because the roofing easily provides for the required air space already.  Metal, tile, and slate roofing systems are examples of such roofing systems where a radiant barrier can be easily incorporated.

Equally as important as the air space on a radiant barrier is the requirement that a radiant barrier remain clean and dry in any application.

The picture below shows a batten/counter batten system with a slate/tile material with a radiant barrier on top of the counter battens.  The radiant barrier is installed on the top of the counter battens in non-watertight applications.  This allows the radiant barrier to remain dry while also achieving the 3/4" air space requirement.

If the roofing material is watertight, installing the radiant barrier on top of the felt with the batten on top of it would be sufficient.

We recommend our Xtreme SOLID (vapor barrier) radiant barrier product for roofing applications.

Don't Do This...

Because a radiant barrier needs an air space on at least one side, installing it directly below felt and shingles will NOT allow the radiant barrier to block any radiant heat.  Instead, the heat from the shingles and felt will conduct all the way through the barrier, into the attic, and eventually in the living spaces.

Instead Do This...

If an asphalt shingle roof is being installed, you should install the radiant barrier to the underside of the roof decking or roof rafters in the attic space below.

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Bubble Insulation Applications

Note:  Our bubble insulation products are solid vapor barriers (i.e. not vapor permeable) and therefore, serious moisture, health, and durability problems can result from improper installation.

Wall Installations

Most people are familiar with extreme heat found in attic, but there is secondary method of heat transfer into a building structure; through the walls.  Radiant barriers installed as house wraps during new construction projects or bubble insulation retrofitted into wall systems can block a majority of the heat that transfers through the walls into living spaces.

Installation Instructions:

• Side Walls
  • 2" X 4" wall studs with R-13 un-faced - Assembly R-Value 16.0 (horizontal heat flow) - achieved by creating a 3/4" air space between bubble insulation and interior wall.
  • 2" X 6" wall studs with R-19 un-faced - Assembly R-Value 22.0 (horizontal heat flow) - achieved by creating a 3/4" air space between bubble insulation and interior wall.

Radiant Flooring Installations

Radiant floor heating has been in use for centuries and radiant barriers help to retain the heat generated by the radiant heating system blocking it from escaping into the ground.  Radiant barrier bubble insulation is extremely tough and pliable, easy to install, and is an excellent vapor barrier for all your radiant floor heating applications.

Installation Instructions:

• Radiant Heating in Concrete - R-Value 1.1 (downward heat flow)
• Radiant Heating under Wood Joists     R-Value: 17.0 (downward heat flow) - achieved by creating a 6" enclosed air space above the bubble insulation below the flooring above.

Crawl Space Installations

Radiant barrier bubble insulation installed in crawl spaces below a building structure reflect the heat flows that are flowing downward from the flooring back up into the flooring at a 95-97% rate providing increased comfort and heat retention.  The temperature of the cold floors which cause cold feet will be raised while your heating bill is reduced, providing for increased comfort.  As heat is reflected back into the living area, it warms other objects which then radiate heat back into the room, further increasing your living comfort.

Installation Instructions:

• Crawl Space - R-Value 16.8 (downward heat flow) - achieved by creating a 9 1/2" enclosed air space between the bubble insulation and the flooring above.

Metal Building Installations

Radiant barrier bubble insulation not only blocks 95-97% of the radiant heat striking its surface, it also provides the necessary thermal break to eliminate condensation problems in metal buildings.

Roof Installation Instructions:

• New Metal Roofs (open interior)
  • With Thermal Break - R-Value 9.2 (downward heat flow)  R-Value 4.1 (upward heat flow) - achieved by creating a 3/4" enclosed air space between roofing and bubble insulation and an 8" air space between insulation and the interior finish (if exists).
  • Without Thermal Break - R-Value 7.6 (downward heat flow) R-Value 3.9 (upward heat flow)- achieved by creating a 3/4" nominal enclosed air space between roofing and bubble insulation and an 8" air space between insulation and the interior finish (if exists).
• Retrofit Metal Roofs (open interior) - R-Value 11 (downward heat flow) R-Value 4.4 (upward heat flow) - achieved by creating an 8" enclosed air space between the roofing and the bubble insulation.

Wall Installation Instructions:

• New Metal Walls (open interior)
  • With Thermal Break - R-Value 5.6 (horizontal heat flow) - achieved by creating a 3/4" enclosed air space between the exterior finish and the bubble insulation and an 8" air space between the insulation and the interior finish.
  • Without Thermal Break - R-Value 4.7 (horizontal heat flow) - achieved by creating a 3/4" nominal enclosed air space between the exterior finish and bubble insulation and an 8" air space between insulation and the interior finish (if exists)
• Retrofit Metal Walls (open interior) - R-Value 4.5 (horizontal heat flow) - achieved by creating an 8" enclosed air space between the exterior wall and the bubble insulation.

Post Frame / Pole Barn Installations

Radiant barrier bubble insulation can also help block radiant heat in post frame building structures inhibiting dew point condensation problems.  Our bubble insulation also does not provide a growth medium or nutritive value for fungus, insects, or rodents.

Roof Installation Instructions:

• New Post Frame / Pole Barn Roofs (open interior)
  • Bottom of Purlins - R-Value 9 (downward heat flow) R-Value 4.4 (upward heat flow) - achieved by attaching to the underside of 2" x 4" roof purlins creating a 2" enclosed air space between bubble insulation and metal exterior roof.
  • Above Purlins - R-Value 6.4 (downward heat flow) R-Value 4.3 (upward heat flow) - achieved by attaching to the top of 2" X 4" roof purlins with at least a 3/4" drape between purlins.
• Retrofit Post Frame / Pole Barn Roofs
  • Bottom of Purlins - R-Value 9 (downward heat flow) R-Value 4.4 (upward heat flow) - achieved by attaching to the underside of 2" x 4" roof purlins creating a 2" enclosed air space between bubble insulation and metal exterior roof.
  • Bottom of Truss - R-Value 10 (downward heat flow) R-Value 3.7 (upward heat flow) - achieved

Wall Installation Instructions:

• New Post Frame / Pole Barn Walls (open interior)
  • Inside the Girts - R-Value 5.3 (horizontal heat flow) - achieved by creating a 1" air space between the bubble insulation and the outside panel.
  • Outside the Girts - R-Value 4.7 (horizontal heat flow) - achieved by creating at least a 3/4" air space between the bubble insulation and the outside panel.
• Retrofit Post Frame / Pole Barn Walls (open interior)
  • Inside the Girts - R-Value 5.3 (horizontal heat flow) - achieved by creating a 1" air space between the bubble insulation and the outside panel.

Masonry / Basement Block Wall Installation

Radiant barrier bubble insulation is excellent as a basement wall insulator.  It performs as a vapor retarder, resists fungus and mold, and also controls dew point problems.  R-Values are unaffected by a damp moisture basement environment unlike fiberglass insulation.

• Basement / Masonry Wall

Other Installations

Radiant barrier bubble insulation applications are only limited by your imagination.  Below are a few more installation applications.

Installation Instructions:

• Hot Water Heater - R-Value 4.5 (horizontal heat flow) - achieved with 5/8" air space between product and water heater.
• Garage Doors