When installing Radiant Barrier with the Open-Ridge or Flat-Top Method, your main objective is to get foil between the roof deck and the insulation. Pretty simple right? You are not trying to make the foil air tight. All you are trying to do is bounce the radiant heat that is coming off your roof back toward the roof and outside. 

Do's and Dont's:

• Don't- Overthink this; it's really pretty simple
• Don't - Worry about the impossible and hard to reach areas. Foil is like shade. It has a cumulative effect. The more the better.
• Do - Work on the big wide open areas first, then worry about the harder areas.
• Do - Get a helper. The install will go much faster with fewer headaches.
• Don't - Concern yourself about the hot air that might accumulate; it's not toxic waste. Just remember this: holes in the bottom and holes in the top of the attic. Is there a path (no matter how) for air to flow from the bottom holes to the top holes? If yes, then your good. If not, create a pathway.
• Don't - Distress if it's not pretty. Ugly, crooked, wrinkled foil works just the same as perfectly smooth pretty foil. Remember, it is your attic, not your living room.
• Don't - Tape the seams. It's is a waste of time and all it does is make it look pretty.
• Don't - Worry, yes you can do this. It's actually pretty hard to screw it up.
• Do - Think safety first!

Supplies Needed:

• Staple guns - One for each person. Front squeeze PowerShot staplers are good. Or, electric or air driven are fine. Don't use a hammer staple; you won't be able to see the rafters to staple into. Attach a colored string or ribbon to the staple gun in case it falls into the insulation.
• Staples - 1/4" or 5/16" These sizes work perfect. Plan for about 1 staple for every 2-3 square feet of foil. 1,000 staples should take care of 2,000-3,000 square ft. of foil then worry about the harder areas.
• Lights - Get a couple of clamp lights, at about $6.00 each they are a good investment and they will clamp on to anything and can be moved around easily. Use CFL bulbs to keep from burning yourself.
• Measuring tape - to measure foil, pretty obvious.
• Utility knife - A standard box cutter type utility knife with some extra blades. Don't use scissors since the foil will dull them very quickly. Some installers like using a hook carpet blade.
• Standing platform - A few 2x6's boards about 8 feet long work great or plywood cut into 1 ft by 8 ft sections. They are strong and easy to move around and you want to minimize compressing any insulation in your attic. If you will be using a ladder in the attic get a sheet of plywood at least 4'x4' to put across floor ceiling joists to create a solid base to place ladder.
• Foil tape - Not needed to tape the seams, but will come in handy if you need to patch the foil around something. Do not use duct tape; use foil air conditioning tape, it is available in your air conditioning supply department at your home improvement store.
• Dust mask that fits tightly and is of good quality, or you can spend about $20 and buy a half-face respirator with P100 Particulate Filter.

foil air conditioning tape - good for sealing seams/cuts	3M respirator/air filtration mask
Powershot staple guns - manual & electric models	close up of the manual Powershot staple gun
3M half mask respirator	closeup of the P100 pancake filters used on the half mask respirator
another staple gun option - the Cobra by Arrow	Taping a nail to a broom handle (or a 1x2 board or a PVC pipe) is useful for pushing pieces to the eaves in an over the attic insulation installation

Buy DIY Radiant Barrier Foil Insulation.