Research by the Florida Solar Energy Center (FSEC) found that radiant barriers work best when installed with foil-face down (towards the building interior) and applied under the roof sheathing. Foil insulation underlayment is recommended under a metal roof, and in most cases, the shiny side should be facing up, but there's a catch. Foil insulation is a radiant barrier, and it works by reflecting heat from the metal, but for it to do its job, there has to be a layer of air between the roofing and the foil. Installation Summary: Install unfaced mass insulation between rafters ensuring a minimum of 1" ventilation space between the mass insulation and the underside of the roof decking. Unroll and staple reflective insulation to the under side of the rafters. Seal all seams with aluminum foil tape. The radiant barrier creates a cooler attic which helps reduce cooling costs. There are also some comfort improvements. Overall, when installed properly radiant barriers can provide reduced energy costs and cooler attics. The sheathing products are pretty cost effective because they add little additional cost. So, without an air space, you cannot have radiant heat. Without radiant heat there is no way to have a “Radiant Barrier”. In fact, because of the conductive nature of pure aluminum, if you install radiant barrier foil WITHOUT the required air space it will actually work AGAINST you and INCREASE Heat flow.
This works well for most insulation materials, because conduction is the main way they prevent the movement of heat. Foil insulation works slightly differently, however. It means that foil insulation is going to have a higher U-value, but may well perform better than expected in the real world.
Foil-faced batt insulation helps keep interior heat inside the living area when placed in the attic with the foil side down. This also helps prevent moisture migration to the attic through the batts. The same moisture and radiant barrier principles also work in wall insulation.
Radiant barriers and reflective insulation systems work by reducing radiant heat gain. To be effective, the reflective surface must face an air space. Radiant barriers are more effective in hot climates than in cool climates, especially when cooling air ducts are located in the attic.
In order to prevent condensation from forming, a vapor barrier should be placed on the warm side of your insulation to stop warm, moist air from condensing on a cold surface inside your wall. In cold climates like Canada, for most of the year the vapor barrier should be on the inside of the insulation.
Faced insulation has Kraft paper on one side to act as a vapor retarder and help prevent moisture from entering the wall cavity. Unfaced insulation is insulation only, for use when a vapor retarder isn't needed.
By combining radiant barrier foil with spray foam insulation you create two defenses for reducing heat flow into your home. So you can't just glue it to the shingles and add the foam afterward. The barrier reflects only radiant heat, which forms only in an air space.
5 Answers. Rigid foam insulation is usually a qualified vapor barrier. However, an installation between the studs can pose a challenge. To complete the vapor barrier you would want to foam-seal or tape all the sides where the rigid meets timber, because these gaps will facilitate vapor flow.
In general, installing a radiant barrier in your attic (or on your roof) will not affect your cell phone's signal. However, if you already have a weak signal, then installing a radiant barrier may push it to the point that you may have some reception issues.
With insulation, a higher R-value means more effective insulation. The insulation we are talking about is made of fiberglass and is commonly found in most homes. A radiant barrier, on the other hand, actually blocks and reflects heat back to where it came from, rather than just slowing down the process.
Our Selection of The 5 Best Radiant Barriers: Radiant Barrier Insulation by RadiantGUARD. 1000 sqft Diamond Radiant Barrier Solar Attic Foil Reflective Insulation. Reflectix ST16025 Staple Tab Insulation. 1000sqft (4ft Wide) of NASA TECH Commercial Grade Perforated No Tear Green Energy Radiant Barrier.
Radiant barrier roof sheathing helps to improve comfort in the building interior during the warm summer months and reduces energy costs. Because heat always moves from hot areas to cold areas, radiant barrier sheathing also prevents heat transfer from the warm interior during the cooler winter months.
If you are installing any type of roof that has an air space (either built in by the shape of the tiles or because of a batten system), then you should most definitely install a radiant barrier! These types of roofs are usually clay tile or slate roofs, metal shingle roofs & some standing seam metal roofs.
By blocking the mass insulation from absorbing heat and emitting it back to the roof, a radiant barrier can decrease the roof temperature at night by over 5 degrees. In short, radiant barrier should not void any shingle manufacturer's warranty and will not damage roof shingles or any other roofing material.