Radiant barrier insulation reflects radiant heat and prevents it from passing through the attic. It can be a reflective foil painted on a surface, a sheet of aluminum or an insulated sheathing such as oriented strand board (OSB) with foil attached to one side.

While fiberglass and spray foam insulation work well to prevent conductive and convective transfers, radiant barriers are the only material that stop radiant transfer altogether. For more information about Radiant Barrier Foil Houston read the article below.

Reflective foil insulation, also known as radiant barrier insulation, works by preventing heat flow through walls and roofs. This reduces the amount of energy needed to keep a building warm, which in turn lowers utility bills and increases the resale value. It’s a great choice for homes in hot, humid climates that struggle with condensation and mold development.

In addition to keeping a home cool, reflective insulation can prevent moisture build-up, which is a major issue in many homes and buildings. Moisture can damage or weaken drywall and wood structures, leading to mold and mildew growth. Foil insulation, like Prodex, is a class 1 vapor barrier and will limit the transfer of moisture into the home or structure, keeping walls and roofs dry and safe from potential mold and mildew growth.

Foil insulation has a low R-Value, but it is effective when installed correctly. To maximize its effectiveness, it must be installed with a 3/4 inch gap left between the material and the wall or ceiling. This airspace allows the material to perform its job of reflecting the sun’s heat.

If you’ve ever placed a silver foil over a coffee thermos to prevent the sun from warming it up, you’ve seen reflective insulation in action. It’s a simple concept that has been used by people for centuries to make their lives more comfortable.

Foil-Backed Sheathing

Foil radiant barriers can be applied to the underside of the roof sheathing in homes and commercial buildings. They help lower cooling costs by reflecting the sun’s radiant heat away from the building, thus reducing energy loss. The foil surface also helps keep the attic space cool, reducing the air temperature and energy needed to cool the building. In hot climates, a radiant barrier can cut cooling costs by 10 to 15 percent when added to standard ceiling insulation such as R-19.

Oriented strand board (OSB) with a layer of low-emitting aluminum foil attached to one side is a common form of sheathing that serves as a radiant barrier. This type of sheathing is typically used in attics but can also be installed in wall systems. This sheathing is not as energy efficient as traditional thermal insulation such as fiberglass batts. This is because the foil only reflects radiant heat, not conductive heat, which can still flow through the OSB and contribute to the Delta-T.

The reflective surface of a radiant barrier can degrade over time, decreasing its ability to reflect heat. In addition, if the foil is not protected from moisture, it can develop mold and mildew problems. To minimize this, the radiant barrier sheathing should be protected from moisture by covering it with a vapor retarder.

This sheathing is available in both single-layer and double-layer formats. It is used in new construction and remodeling with furred masonry, wood or steel framing. It can be used as the sole sheathing in wood frame construction or as a bottom layer over a vapor retarder in non-fire-rated framing. It is also commonly used as a sub-surface sheathing in metal stud construction and for nonfire-rated foundation walls. Foil-backed gypsum board is also available in both single- and double-layer formats. It is used for interior walls and ceilings in new construction or remodeling with furred masonry, wood or stucco framing, and as a back-up layer for sheathing in fire-rated and non-fire-rated construction. It is an ideal choice for sheathing in wood framing, especially when a vapor retarder is required.

Foil-Backed OSB

A radiant barrier is an effective energy-saving insulator that can reduce cooling costs by lowering ceiling heat gains. It does this by absorbing the sun’s radiant energy before it can reach the living spaces of a home or building.

One common type of radiant barrier sheathing is oriented strand board (OSB) that has a thin layer of low-emitting aluminum foil attached to it. This type of sheathing is typically applied in attics, but it can also be used in wall systems. The foil layer lowers the Delta-T, and it helps cool the top of the OSB sheathing that will later be covered with shingles or other roofing materials.

The foil can be either single or double-sided. The dual-sided product offers the same benefits as a single-sided foil but allows the white side to face the airspace (or ceiling of the attic) for aesthetic purposes. Some builders prefer the perforated version of this sheathing, which allows moisture vapor to pass through it without creating condensation.

Foil-backed OSB is a popular choice for new construction because it saves time and labor by serving as both roof sheathing and radiant barrier at the same time. It is important to note that a radiant barrier sheathing does not replace the need for an adequate amount of attic insulation, however.

When it comes to stapling foil sheathing into an existing attic, contractors should be careful not to cover the entire roof surface, as this can lead to thermal bypass around the rafters. Staples placed too close together can cause a buildup of hot air near the joists and may even melt the shingle overhang.

Another potential issue with foil-backed sheathing is the fact that it can cause a loss of R-value if the sheathing is too thick. To avoid this, builders should use a sheathing with an R-value that is appropriate for the climate in which they are working. For instance, if they are working in Florida, where the cooling load is very high, they should use a higher R-value sheathing. The insulating value of the sheathing will be reduced, but it will be sufficient to reduce cooling loads and save energy.

Liquid Foil

Liquid Foil is a water-based coating that can be applied with a roller, brush or airless spray. It protects non-absorbing surfaces during transport, storage or construction and renovation. It is very easy to apply and can be easily removed without leaving residue or adhesive. Liquid foil can be used on glass, (powder-coated) aluminum and steel, closed concrete, brick, sandstone, stone tiles, natural stone, ceramic coverings and plaster models. It can also be used as a primer before applying sealers, paint or plaster. It is suitable for a wide range of substrates and it can be used in dry, unventilated rooms, such as sanitary areas, kitchens and cellars. It is compatible with most silicone sealants, solvent-free coatings and can be loosened with water.

The purpose of the radiant barrier foil is to stop the transfer of heat through radiation by reducing the amount of absorbed energy from the sun. The foil acts much like a shade tree, reflecting the radiant heat back into the air so that we don’t feel it on our skin and have to run our air conditioners.

Generally, radiant barriers save 5 to 25% on cooling costs. They work best on single story ranch style homes, although two story houses can see a smaller percentage savings. It depends on how well your home is insulated and how much of your roof surface is covered by the radiant barrier.

A radiant barrier is not designed to be a vapor retarder, meaning it can’t stop moisture in the attic from causing mold and fungal growth. When this happens, the radiant barrier may actually achieve the opposite of its intended effect, transferring the heat from the attic into the house.

If you’re considering a radiant barrier, look for a product with perforations to allow vapor transmission, such as our Fi-Foils Radiant Shield. It offers industrial strength and can be paired with our reflective insulation products for optimal results. The result is a well-insulated attic that will reduce your utility bills and help protect your home. If you’re interested in seeing how a radiant barrier could benefit your home, contact us.