The Open-Ridge Method is the Standard Method is used for many roofs. Basically, the foil is stapled on the bottom of the rafters and run almost to the top of the rafters. A slot is left along the ridge and around roof vents to allow air to flow from the soffits to the top of the attic and then vent out the top of the attic. Radiant barrier should be installed so that it does NOT interfere with attic ventilation.

If you have a tall attic or high ridge, consider the Flat Top Installation Method. This method will keep you from having to climb ladders inside your attic. With this method, you will run the foil up the roof slopes about 7 ft. Then create a grid or a false ceiling for the foil to run across the top. Complete FlatTop install instructions HERE.

Run the foil horizontally ACROSS the rafters Left-Right. Do not try to run the foil up and down the rafters from top to bottom. You want to cover the largest area possible. Use either a measuring tape or just count the rafters. The rafters are usually 24” or 2 feet apart. Count them up and add about a foot to make sure you don’t run short.

Cut pieces outside the attic. The best way is to cut several pieces at a time and work in sections. The driveway works well. Use a standard utility knife and have some extra blades handy. Don’t use scissors, they will quickly get dull. Use a cardboard box as a cutting board. If you plan ahead, you can cut 5-10 pieces at a time and minimize trips into the attic.

Here is cool trick. Take the ENDS of a cut piece of foil and pull them together. Then fold or roll up the foil. When you are in the attic, you and your helper can each grab and end and pull it out full length. This method will keep the foil from getting folded up or wrinkled. The foil is VERY DURABLE. You do NOT have to worry about it tearing or ripping while handling.

TIP: Get yourself TWO staple guns. They are about $20 at home improvement stores like Home Depot and Lowe’s and use a “Front Squeeze” method that is much easier on your hands then the old type staple guns. Figure about 500 staples for every 1000 square ft. of foil. Electric staplers work fine, and there are some really good new staplers for about $25. Use 1⁄4” or 5/16” staples. Tie a colored string or ribbon to the stapler in case you drop the staple gun in the insulation to help find it. Complete list of Radiant Barrier Supplies

Most installs go best when you start at the bottom with larger pieces and work up. This enables the first piece to be pulled across and level. Use your helper and pull the first piece across. You can EITHER leave a small gap (3-5”) at the bottom OR put the foil all the way down the rafter. IF you go all the way down MAKE SURE you have some open soffit vents in the section to provide intake attic ventilation. If you have no soffit vents, or lack of vents leave a gap at the bottom.

Another method is to create a “Skirt”. This method should ONLY be used if you have adequate soffit vents in the area where the skirt method is used. The skirt method is good if you plan on adding additional insulation later. It will act as “back stop” to keep the insulation from blowing into the soffits. The RED line shows how the foil is folded back.

Pull the first piece across the lowest part of the roof. You can either staple both ends, then come back and put 3-4 staples on the rafters in between. Or, staple one end and pull the foil tight from the other end as one person staples the foil to the rafters. This will result in a "tighter" look. AtticFoil is so strong you can skip 1 or 2 rafters without stapling. The foil will not be as "tight", but will not fall down.

Proceed moving up with your next piece of foil. It does NOT have to be pretty. If you get the foil between the roof and the attic insulation, the foil will work correctly. SEAMS can be overlapped, butted against each other or leave a small gap between pieces. You DO NOT NEED TO TAPE THE SEAMS!! It will not have any effect on the foil performance. You are using PERFORATED foil. You are NOT trying to make it airtight. All foil tape does is to make it look prettier.

Either cut around bracing and other obstacles or just go over them. The foil does not have to be perfectly smooth. Use a roll of foil air-conditioning tape to patch foil back together after cutting. When cutting around objects, don’t worry if it is not “tight”. A few gaps are OK.

Sometimes the foil and the attic framing supports don’t line up perfectly. Notice the 10" gap below the horizontal support in the picture above. You can either cut a strip and staple below the support. Or, you could go OVER the TOP of the support and encapsulate it in foil and connect to the bottom piece of foil.

Continue to work your way up to the ridge. STOP the foil about 3-6” from the ridge. This gap will allow a pathway for air to “pool” in the top of the attic. The hot air will then exit the attic through either your ridge vents, wind turbines, electric or solor fans or static vents. Homeowners really tend to get too concerned about this. It's OK if your "holes" in the attic are not at the ridge. Just think of the air like water and it is "draining" out the top.

Cut holes below ALL exhaust vents about 6” larger then the actual vent holes. It is important to create a pathway for cool air to come in the bottom of the attic and heated air to go out the top of the attic. With proper ventilation foil will ONLY increase shingle temperatures 2º-5º which is acceptable and will not damage or shorten the life of your roof.

Gables – Run the foil across the framing. Leave a small air gap at the bottom. Do not cover gable vents.

Truss Type Framing – These can be a little tricky because of all the supports. However this type of construction usually has long open areas to run foil. Pull a long piece of foil and staple on the ends. For truss type roofs it is often best to start AT THE TOP and work down. If the foil piece is wider then the rafter, staple above each support and use support as a “Cutting Board”. Then wrap around support and staple to rafter on other side of support. The video above shows how to do the "T" cut.

Finished Attic – Notice the open slot at the ridge for ventilation. Use this method in lower attics and dormers even if there are no exhaust vents. The air will move out and then make its way to the upper attic sections.

Finished Attic – Notice the duct on the attic floor. To make install easier, you can cut or pull down the ducts straps. Then, when complete, nail the straps back into the rafters through the foil. Or, if codes will allow it, leave the ducts on the ground. Keep them straight and try to eliminate sharp turns. Then, "Bury" the ducts with blown in insulation.