I like foil. Let me just get that out there in the open. Maybe it was growing up with aluminum foil instead of plastic wrap (I STILL cannot use plastic wrap without wadding it up into a huge mess) or maybe it just brings out the trailer park side of me. Either way, it is cheap to buy and simple to install, if you call contorting your body while crawling in a 100+ degree, dirty, fiberglass-filled attic simple. Ok, "simple", but not "easy"

Believe it or not, this became a hobby for me. I wanted one for my house, so I talked with the manufacturers, distributors, installers, and people who had it in their house. My next step was to actually buy some and start stapling. You get into the argument of where you should install the foil. do you lay it over the insulation? do you staple it to the backside of the rafters? do you staple it between the rafter? Who knew?

You can actually do any of the three methods. They all have their pros and cons. Stapling it between the rafters gives the most flexibility as far as continuing to grant you access to the rafters before during and after installation, but is certainly the most labor intensive way to do it. When done this way, you merely need to make sure that you are leaving a 2 inch air gap between the roof plywood and the radiant barrier.

Stapling the foil to the underside of the rafters is generally what I have always done. this allows me to install it faster than between the rafters and yet still grants me the ability to add more insulation later, change attic wiring, or add new things (like a suntube) easily.

Laying the foil out on top of the insulation is certainly the easiest way to install it, but you end up with a long term problem. A radiant barrier depends upon having the original shiny surface to reflect the heat. Anything sitting horizontally in an attic will eventually gather dust. that dust buildup will completely negate the bonuses of your radiant barrier. The foil is basically fancy aluminum foil. imagine taking 2 pieces of aluminum foil and gluing them on either side of a stronger wrapping material (usually polypropylene or something similar similar) and poof, you now have a radiant barrier. Aluminum excels at both reflecting heat and transferring heat. it is a great conductor (hence aluminum cooking pots). This is where you get into the 2 inches of airspace. If the foil is given its space, it does its job wonderfully. If it is touching something (like dust buildup), then you have totally blown its sweet spot. Right now I am using Armafoil brand for radiant barrier, but I have used several types. I have even showed what I buy to several other distributors to see if they can match the quality and price, but so far, no takers.

The neatest thing about foil is the expression on people's face when you finish the job and come up with a line like, "now the space aliens can't scan your brain". Hey, after the beating I take crawling around in someone's attic, don't I deserve a little fun?

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