It depends, if you are installing typical asphalt shingles without an airspace then the answer is usually NO. Here is complete information on radiant barrier directly under shingles. 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. If you are using a batten system (wood nailers on top of the deck), then you will automatically have the required airspace for a radiant barrier to work properly.
Radiant heat is the transfer of heat from one object to another object without direct contact. Energy is transferred in waveform, similar to how sound travels. This energy is then converted to heat when it comes in contact with another surface. The amount of energy converted is usually determined by the reflectivity of the surface receiving the energy. Every object has some level of ability to absorb or reflect radiant heat. For example: black leather seats absorb nearly all the radiant energy that strikes them - that's why they get SO hot. If we covered black leather seats with radiant barrier AtticFoil®, the seats below the foil would only get a few degrees above the air temperature because rather than absorbing the heat, the foil is reflecting the heat waves back off the surface of the seats. Remember we are talking about heat, not the light.
The same goes for a roofing assembly. The tiles, or shingles, will get hot from absorbing radiant energy (heat) from the sun. This heat will re-radiate across the airspace below the tiles and be absorbed by the roofing underlayment. Roofing underlayments, like typical roofing felt, are usually not very reflective; therefore, they will act just like the black leather seats mentioned above and absorb the heat. The underlayment will then transfer this energy by conduction (heat transfer through objects that are touching) through the roof deck. Ultimately the roof deck will get very hot and then re-radiate this energy across the attic space which will be absorbed by the attic insulation. Then the heat will travel once again by conduction through the attic insulation and into the home. When heat is traveling through objects that are touching, it's called conductive heat transfer. When an air space has to be crossed to get to the next object, the heat converts to radiant heat form - this is where your Radiant Barrier comes in.
You only get one chance to do this right. Installing radiant barrier AtticFoil® under your tile or metal roof is almost like putting a giant tree over your home. Bang for the buck, you can not beat it. Your home will have immediate energy savings, and be more comfortable year round. If you have chosen to spend the extra money on a high quality tile or metal roof, why not spend just a little more to make the roof pay for itself through energy savings from a radiant barrier?
Your roofing company should be able to easily install AtticFoil® Radiant Barrier under your new roof. All they have to do is add one additional layer on top of the waterproofing layer (below the battens). Just a few staples or plastic caps will hold the AtticFoil® in place until the battens are installed over the foil. AtticFoil® is perforated and is not a vapor barrier, so it will allow moisture to dry out and not get trapped in the roofing assembly.
If you are a roofing contractor installing metal or tile roofs, why aren't you installing a radiant barrier on every job? Your customers are more than willing to pay for the small additional cost of installing a radiant barrier since they will definitely get the money back in energy savings. All you have to do is explain how it works (the video above will help), install the radiant barrier properly and make some extra money on your next roofing job. Before you know it, you will be including AtticFoil® Radiant Barrier on every job! Contact us for special contractor pricing on both our 48" wide Radiant Barrier Product and our 60" wide Radiant Barrier Product
|Metal shingles over a wood batten system. This image highlights the 2x2 wood battens that create the required airspace. By installing AtticFoil® radiant barrier under the battens, 97% of the the radiant heat that would have been absorbed by the roof deck is now reflected.||Generally a 1/2" air space or more is ideal between the radiant barrier and the shingle or tile roof. Roofing compaines, please contact us at 800-595-8772 We want to supply you with the best radiant barrier available. Plus, great customer service and same day shipping. Also, we manufacture a 60" product for larger applications.|
|Installing the radiant barrier foil under a metal roof is quick and easy. Installers just roll it out and cut it with a knife. Use a few staples to hold in place, then install battens. Be careful to work so the sun won't reflect in your face, it can be blinding. Sunglasses are highly recommended.||Installing corrugated metal roofs over an old roof without doing a tear-off is rapidly gaining popularity. The preferred installation method would be to install a new waterproofing layer, then radiant barrier foil, battens or furring strips (1' x 4" in this picture) and then the new corrugated roof. Economical, effective and energy efficient!!|
|Roll, Cut, Staple. It's that simple. Then install battens and this roof will save the customer thousands of dollars over the life of the roof.||When you stand inside this attic, it is hard to tell whether the sun is shining or not. Since so much of the heat is reflected before it enters the attic, it feels like a cloudy day.|
|Radiant barrier foil installed under wood battens before a metal roof is installed. Metal roofs are a big investment, and look great. Installing a radiant barrier now, will save energy and help offset the additional cost of a metal roof.||Finished metal roof with radiant barrier installed below the metal roof. Considering the expense of metal roofs, it is a small additional cost to install radiant barrier during the roofing installation.|
|This is a close up of the space (air gap) provided by using a concrete tile shingle. Radiant heat is actually easier to control than conductive heat since it can be reflected by using a radiant barrier.||Spanish tile, clay tile or slate roofing systems are perfect to install a radiant barrier on top of the roof. All these systems provide a natural air space and and easy way to install radiant barrier on top of the waterproofing layer to keep radiant heat out before it ever enters the attic.|
|Here is a framed building with no deck utilizing radiant barrier foil; this is a great way to get full coverage.||The foil has an air space on both the bottom and the topside; the corrugations in the metal allow for air space.|
|You can install the foil one strip at a time or all at once, and then add the roofing panels/sheets over the foil.||This is the view of the foil from the underside of the roof, see how it is open to the air space below the roofline?|
|With curved tile roofs, the foil can be attached directly to the deck and the tiles can be attached on top, without a batten system.||This customer took advantage of the natural air space created by the tiles to use a radiant barrier on his entire roof so he could get maximum coverage.|