Radiant Barrier Decking

Ra-flect™ Radiant Barrier Sheathing:

There are several companies who offer sheathing products with aluminum foil laminated to the back. However, these pre-laminated sheathing sheets are not recommended as the perforations in the aluminum sheets tend to get plugged up by the adhesives causing and unintended vapor retardant. This vapor retardant could stop the passage of water vapor through the material causing condensation to form at the roof decking leading to mold and/or rot.

With our Perforated Ra-flect™ Radiant Barrier, you can make your own durable reflective sheathing for a fraction of the cost. Just staple our 48” wide foil products to regular OSB or Plywood sheathing for a superior product.

Installation Tips:

  • Use our industrial grade perforated Ra-flect™ Radiant Barrier for this job
  • Unroll 51” wide Ra-flect™ Radiant Barrier over the sheathing and staple it in place.
  • Cut foil off at the end of the sheathing.
  • You have just made reflective roof decking at a savings of about 35 cents per sq ft.
  • When installing, face aluminum side down toward the attic space.

Cathedral Ceiling Installation

Ra-flect™ Radiant Barrier Between Rafters:

This installation method holds your insulation away from the roof decking, providing a 3/4" minimum space where the reflected radiant heat can be ventilated. This method will reflect radiant heat gain from the sun during the summer and the Radiant Barrier/insulation combo will help to keep heat in during the winter.

Installation Tips:

  • You must use Perforated Ra-flect™ Radiant Barrier when installing in a cathedral ceiling.
  • Run the 25.5” wide strips parallel to roof rafters as shown in the image.
  • Staple the appropriate width material between joist leaving 3/4” to 1” airspace between the Radiant Barrier and roof decking.
  • Fill the remaining joists space with regular batting type insulation. Adding an optional 2x2 furring strip of wood will give even more space for insulation.
  • Attach drywall or interior finish to bottom of roof rafters.

Ra-flect™ Radiant Barrier Rafter Wrap Method:

This installation is similar to the method mentioned above, however, this installation would be considered a bit easier by most. The results of this installation method will be very similar to the method above, however, by wrapping the rafters additional protection against thermal bridging will be attained. I this installation method full 51” Ra-flect™ Radiant Barrier sheets are run perpendicular to the direction of the roof rafters, allowing the material to reach inside each cavity approximately 3/4” away from the roof decking.

  • You must use Perforated Ra-flect™ Radiant Barrier when installing in a cathedral ceiling.
  • Run Ra-flect™ strips perpendicular to the direction of the roof rafters.
  • Allow material to wrap around each rafter inside each cavity stopping and stapling at about 3/4” to 1” from roof decking.
  • Pull the material taunt across the cavity and staple on opposite side at 3/4” to 1” from roof decking.
  • Run Ra-flect™ strip over the next rafter and into the next cavity.
  • Overlap 51” Ra-flect™ strips by roughly 2” on each row.
  • Fill the remaining rafter cavities with regular batting type insulation.
  • Attach drywall or interior finish to bottom of roof rafters.

Floor Installation

Ra-flect™ Radiant Barrier Under Floor Installation:

Our Ra-flect™ Radiant Barrier can be used under an elevated floor to cut down on heat gain or heat loss through the flooring.

Installation Tips:

  • Perforated Ra-flect™ Radiant Barrier is recommended for this job
  • Unroll the Ra-flect™ Radiant Barrier and staple to bottom of floor joists
  • Overlap each run by about 2 inches
  • Tape seams to reduce air infiltration
  • Widths: 52” and 25.5”

Ra-flect™ Radiant Barrier in Radiant Heat Flooring:

Radiant heat floors are becoming very popular, however, they have a tendency to loose their heat to the space below. Our Ra-flect™ Radiant Barrier will increase the efficiency of these radiant floors by reflecting the majority of this heat back into the conditioned space.

Installation Tips:

  • Perforated Ra-flect™ Radiant Barrier is recommended for this job
  • Ra-flect™ Radiant Barrier should be sized in width to match your floor joist spacing
  • Install Radiant Barrier directly beneath radiant heat tubing
  • Staple in place or allow the material to rest on top of the floor insulation
  • Add conventional insulation to the underside of the Radiant Barrier
  • Widths for dimensional lumber - 25.5” (24” o.c.) or 51” (3 x 16” o.c.)
  • Widths for manufactured floor joists - 25.5” (24” o.c.) or 51” (3 x 16” o.c.)

Ra-flect™ Radiant Barrier Between Radiant Heated Floors:

When used in the floor between two radiant heated floors, our Ra-flect™ Radiant Barrier helps direct the heat to the zone in which it is needed.

Installation Tips:

  • Perforated Ra-flect™ Radiant Barrier is recommended for this job
  • Ra-flect™ Radiant Barrier should be sized in width to match your floor joist spacing
  • Install Radiant Barrier directly beneath radiant heat tubing
  • Staple in place
  • Typically, conventional insulation is not used, except for sound control
  • Widths for dimensional lumber - 25.5” (24” o.c.) or 51” (3 x 16” o.c.)
  • Widths for manufactured floor joists - 25.5” (24” o.c.) or 51” (3 x 16” o.c.)

Wall Installation

Ra-flect™ Radiant Barrier as House Wrap:

Our Ra-flect™ Radiant Barrier can double as a building wrap to create a “air tight” structure. Our Perforated Radiant Barrier is industrial strength and has the ability to “breathe” (let moisture pass) while still sealing and preventing air infiltration. Not only that, but it will cut down on radiant heat gain or radiant heat loss through your walls. Why not benefit from both properties by installing it as a building wrap?

Installation Tips:

  • Perforated Ra-flect™ Radiant Barrier is recommended (creates air barrier)
  • Non-perforated Ra-flect™ Radiant Barrier is acceptable in some areas (creates vapor barrier)
  • Unroll Ra-flect™ Radiant Barrier and staple to the outside of the wall board or exterior sheathing
  • Tape all seams and around all penetrations
  • Install 1x furring strips if necessary to create 3/4" air space to allow radiant barrier to work. Note: an air space is required on at least one side of the material for proper performance
  • Apply exterior veneer

Ra-flect™ Radiant Barrier on Walls:

Ra-flect™ Radiant Barrier can be attached to the interior side of a wall or knee wall to cut down on radiant heat loss in the winter or radiant heat gain in the summer. Not only that, but this installation technique will help reduce the effects of wind washing on the insulation.

Installation Tips:

  • Perforated Ra-flect™ Radiant Barrier is recommended for this job
  • Unroll the Ra-flect™ Radiant Barrier and staple to the in-side of the wall studs, leaving a 3/4" space between the radiant barrier and the exterior sheathing
  • Overlap each run by approximately 2 inches
  • Tape seams to help reduce air infiltration
  • Install insulation in cavity space left over
  • Ensure that insulation does not make radiant barrier touch exterior sheathing

Attic Installation (New)

Ra-flect™ Radiant Barrier Sheathing:

There are several companies who offer sheathing products with aluminum foil laminated to the back. However, these pre-laminated sheathing sheets are not recommended as the perforations in the aluminum sheets tend to get plugged up by the adhesives causing and unintended vapor retardant. This vapor retardant could stop the passage of water vapor through the material causing condensation to form at the roof decking leading to mold and/or rot.

With our Perforated Ra-flect™ Radiant Barrier, you can make your own durable reflective sheathing for a fraction of the cost. Just staple our 48” wide foil products to regular OSB or Plywood sheathing for a superior product.

Installation Tips:

  • Use our industrial grade perforated Ra-flect™ Radiant Barrier for this job
  • Unroll 51” wide Ra-flect™ Radiant Barrier over the sheathing and staple it in place.
  • Cut foil off at the end of the sheathing.
  • You have just made reflective roof decking at a savings of about 35 cents per sq ft.
  • When installing, face aluminum side down toward the attic space.

Ra-flect™ Under Roof Decking:

This installation is primarily used in new construction or when replacing roof decking. It works by draping the Radiant Barrier over the open roof rafters during construction and stapling it to the top of the rafters.

Installation Tips:

  • Perforated Ra-flect™ Radiant Barrier is preferable for this job
  • Unroll the Ra-flect™ Radiant Barrier over the top of the roof rafters
  • Allow the material to sag about 2 inches between each rafter
  • Staple periodically to hold Radiant Barrier in place
  • Use custom tool as shown for ease of installation and proper sag
  • Overlap runs by approximately 2 inches
  • Taped seams are not required in this installation
  • Nail roof decking on top as usual

Attic Installation (Existing)

Ra-flect™ Stapled to Bottom of Roof Rafters:

This installation is considered to be the best method in hot climates where cooling is far more important than heating. This type of installation will generally keep the entire attic space much cooler compared to a non radiant barrier insulated attic, and will effectively block radiant heat from striking air handlers and ductwork in the attic. Also, any attic air which happens to leak into the return side of the ductwork will be cooler, causing less stress on the cooling equipment, increasing its efficiency and lengthening its life.

Although this installation method is the most efficient, it is also the most challenging and requires the most work and time to install. However, once complete, this is a maintenance free installation method requiring no cleaning as it is generally not affected by dust.

Installation Tips:

  • Perforated Ra-felct™ Radiant Barrier should be used for this job
  • Pre-measure installation areas with tape measure and cut pieces to length on flat surface
  • Re-roll Radiant Barrier into smaller lighter rolls for better mobility
  • Unroll the Radiant Barrier, hold in place and staple to bottom of roof joists
  • Trim around vertical bracing
  • It is generally easiest to apply the strips perpendicular to the direction of the roof rafters
  • Overlap runs by approximately 2 inches, or meet at vertical rafters if installing parallel to rafters
  • Taped seams are not required in this installation

Ra-flect™ Over Attic Floor

This installation method is the most common installation in the north, and easiest way of installing a Radiant Barrier in an existing attic. This method helps to reduce radiant heat gain through the ceiling in the summer and helps to retain interior heat in the winter. This installation method is susceptible to some dust accumulation, however Ra-flect™ Radiant Barrier is a double sided product and will continue to perform, but if left uncleaned, a slight degradation can be expected.

Installation Tips:

  • You must use Perforated Ra-felct™ Radiant Barrier for this job
  • Unroll the Radiant Barrier over the existing attic insulation along ceiling joist
  • Trim around vertical bracing
  • Periodically staple to the ceiling joists to hold in place
  • Overlap strips by approximately 3-4 inches
  • Taped seams are not required in this installation

Installation Intro – Required Tools

A Radiant Barrier installation can be a very daunting task. But with a little know how and the proper tools, any handy man (or woman) can definitely do the job.

There are a variety of different installation procedures depending on a number of factors, and we will address all of the most common applications in this guide. Regardless of the application, one common factor is the required tools for the job.

Required Tools:

  • Staple Gun
  • Utility Knife or Box Cutter
  • Measuring Tape

Safety:

  • Dust Mask
  • Safety Glasses

Optional, but Helpful:

  • Ladder
  • Shop Light

Once you have all of the above tools, check out out the different installation procedures below:

Floor Installations
Attic Installations
Cathedral Ceiling Installation
Wall and House Wrap Installations
Do-It-Yourself Radiant Barrier Sheathing

Raflect Specifications

Laser Perforated Radiant Barrier
Property Value Test Method
Description: Double Sided | Laser Perforated -
Core Material: Polyethylene fabric -
Barrier Material: Aluminum; VaporPhase Thin Film Encapsulation -
Sizes: 17"x235' | 25.5"x235' | 51"x235' -
Thickness: 4 Mils (101.6 Microns) Caliper
Unit Weight: 2.7 oz/sq yd (ASTM D-3776)
Emissivity: 0.05 (ASTM C-1371)
Reflectivity: 95% (ASTM C-1371)
Fire Rating: Class 1 / Class A (ASTM E-84-10 / ASTM 2599)
Flame Spread: 0 (ASTM E-84-10 / ASTM 2599)
Smoke Development: 10 (ASTM E-84-10 / ASTM 2599)
Corrosion: 100% Humidity|PASS (ASTM D-3310)
Fungi Resistance: No Growth (ASTM D-1338)
Vapor Permeance: 6.9 Perms (ASTM E-96 A)
Shear/Tear Strength (Length): 10.47 in-lbs. (ASTM D2261)
Shear/Tear Strength (Width): 17.84 in-lbs. (ASTM D2261)
*Meets ASTM C1313 specifications for Sheet Radiant Barriers for Building Construction Applications.

 

Non-Perforated (Vapor Barrier) Radiant Barrier
Property Value Test Method
Description: Double Sided | Non-perforated -
Core Material: Polyethylene fabric -
Barrier Material: Aluminum; VaporPhase Thin Film Encapsulation -
Sizes: 17"x235' | 25.5"x235' | 51"x235' -
Thickness: 4 Mils (101.6 Microns) Caliper
Unit Weight: 2.7 oz/sq yd (ASTM D-3776)
Emissivity: 0.05 (ASTM C-1371)
Reflectivity: 95% (ASTM C-1371)
Fire Rating: Class 1 / Class A (ASTM E-84-10 / ASTM 2599)
Flame Spread: 0 (ASTM E-84-10 / ASTM 2599)
Smoke Development: 10 (ASTM E-84-10 / ASTM 2599)
Corrosion: 100% Humidity|PASS (ASTM D-3310)
Fungi Resistance: No Growth (ASTM D-1338)
Vapor Permeance: Non Permeable (ASTM E-96 A)
Shear/Tear Strength (Length): 10.47 in-lbs. (ASTM D2261)
Shear/Tear Strength (Width): 17.84 in-lbs. (ASTM D2261)
*Meets ASTM C1313 specifications for Sheet Radiant Barriers for Building Construction Applications.

Average Savings

While results will vary from climate to climate, attic installed radiant barrier will reduce heat gain through the ceiling by roughly 40%, which translates into a 17% average reduction in heating & cooling costs. The local climate and the installation technique chosen, will affect the performance of the radiant barrier, so be sure to choose the right installation for your local climate.

While this 17% figure holds true for many climates using a typical installation, it will vary from place to place. Many independent studies and radiant barrier users have tested their results and reported energy savings varying from as low as 12% up to as high as 39%.

Below is one such independent study in which the attic temperature of two similar neighboring houses where tracked over the course of one day. As you can see from the image below, the attic with radiant barrier(blue) performed quite nicely and stayed very close to the ambient temperatures outside(green) when compared to the house with no radiant barrier(red).

The above study is not meant to give hard figures, rather it is meant to give the potential radiant barrier user/installer the proper information to make the most informed decision possible. With that being said, the list below will give some of the main factors which will affect the performance of a radiant barrier installation.

Factors Determining Radiant Barrier Effectiveness:

  • Attic Ductwork – If ductwork or air handlers are located in the attic, the temperature of the attic area will affect the efficiency of the HVAC system. Using a radiant barrier to control attic temperatures will increase the HVAC system’s efficiency, thus reducing energy costs.
  • Existing Insulation – If existing attic insulation is less than a R39, a radiant barrier installation will help to stop excess radiant heat. Homes with a R39 or higher ceiling-insulation, and have no ductwork in the attic will not achieve much energy savings from a radiant barrier installation.
  • Cold Climates – In climates where the majority of annual energy usage goes towards heating the structure, a radiant barrier on the floor of the attic, above the insulation and ductwork will provide substantial energy savings.
  • Hot Climates – In climates where the majority of annual energy usage goes towards cooling the structure, a radiant barrier stapled to the bottom of the roof rafters will provide maximum energy savings.
  • Mild Climates – In more mild climates where neither heating nor cooling is used much, a radiant barrier installation will not create massive energy savings. However, the radiant barrier will increase the overall comfort of the structure while providing small to moderate energy savings.

How Does Radiant Barrier Work?

In order to understand how and why radiant barriers are so effective at reducing heat transfer, you must first understand how heat transfer actually works.

How Heat Transfer Works:

There are three basic types of heat transfer from least efficient to most efficient; conduction, convection and radiant. I am going to use a kitchen analogy to help explain the different types of heat and the different methods of controlling them.

Conduction is the least efficient method of transferring heat and in our kitchen analogy, that would be an equivalent of boiling water in a pot over a stove. The fire heats the pot and the pot transfers its heat to the water and the water eventually comes to a boil. The key point here is that conduction is the transferred through direct physical contact.

Convection is more efficient than conduction, and in our kitchen analogy would be the use of an oven to heat some food. Convection heat transfer is the process by which heat is circulated in an area through the air and/or fluid. The key point here is that heat is transferred through air/fluid circulation.

Radiant heat otherwise known as thermal radiation is the most efficient type of heat transfer and the best example in our kitchen analogy would be the use of a microwave. Radiant heat is generated when heat from the movement of charged particles within atoms is converted to electromagnetic radiation. In a home or building, radiant heat refers to heat radiated from materials, incandescent lights and the sun. It is also important to note that radiant heat moves through the air without heating the air, instead it will heat the first surface that it touches, and this surface will then re-radiate that heat in the space making it feel warmer when you are in that space. This principle causes interior spaces to feel hotter in the summer and reverse during winter months where interior heat is radiated towards the outside of the structure.

The following images help to explain the difference between conductive, convective and radiant heat transfer.

How Radiant Barriers Work?

A radiant barrier is a reflective insulation type system that offers a permanent way to reduce energy costs. Most people are familiar with traditional insulating materials such as fiberglass, cellulose, Styrofoam, and rock wool. These products use their ability to absorb or resist convective and conductive heat transfer to insulate (R-value). Radiant barriers are not an insulation material, due to the fact they are only a thin sheet of reinforced aluminum foil, however with an air space of 3/4” or more, radiant barriers have a theoretical R-value of 53.

Radiant barriers address radiant (Electromagnetic) heat transfer, the single most efficient type of heat transfer, by reflecting that radiation away from the radiant barrier (as shown in the image above). A typical home will lose heat in the winter and gain heat in the summer and the majority of that heat is radiant heat, so stopping radiant heat transfer in both the winter and summer months is the most effective way to reduce energy cost. Ra-flect™ radiant barrier reduces energy costs in both summer months and winter months because it is double sided, and will keep heat in during the winter months and reflect radiant heat away during the hot summer months. Installing a radiant barrier in your attic is the most cost effective way of reducing your heating and cooling cost while providing the quickest payback(less than a year) of any energy efficient material or product.

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