How Radiant Barrier Works - AtticFoil® Reflects Heat Coming Off The Roof

[EclecticFortune]

Suppose the roof develops a leak. Wouldn't the water drip down the inside of the foil into the eaves area and rot the lumber?

[AtticFoil]

@EclecticFortune It depends. If you start the foil at the bottom and and work up, then most likely any water from a leak will only go a couple of feet before it hits a seam. At that point it would drip down to the sheetrock and you would see a wet spot on the ceiling and have the opportunity to fix the leak. (hopefully before much damage). Any water on the foil would also leave a "trail" which would help pinpoint the source of the leak.

[AtticFoil]

First, I would try to get some form of ventilation. Ideally, you want air coming in the bottom and out the top. As for install method? It really depends if you PRIMARY goal is to reduce cooling or heating costs. Staple up if trying to reduce cooling costs and lay out if trying to reduce heating costs or if you have NO ductwork in the attic. See "best install method" at AtticFoil(dot).com

[dogfan4lyfe]

I live in the midwest with hot humid summers and brutal cold winters. What's best - laying the foil down on top of the insulation on the floor or stapling the foil to the rafters? I only have two gable vents, that's it. My house is old so I have no soffits.

[julebuggy]

Wouldn't the reflected heat in the summer time build up on the roof. The heat going out combined with the heat coming in may raise the temperature of the roof, causing the shingles and roofing materials to bubble. No?

[AtticFoil]

@julebuggy No, shingle and roof temperatures only go up between 2-10 degrees on a roof with radiant barrier. This is generally insignificant to the life span of the roof. The color of the roof can easily make a 30 degree difference alone. Go to RadiantBarrierGuru(dot)com and search on the word BAKE. There is an article I wrote called "Am I Going To Bake My Shingles"

[prdgyair]

hey all , i installed this exact product to my attic rafters in my 2100sq ft house in the DFW metroplex. i installed it in the heat of august to see how much difference it would really make. so? it saved me 1.10 PER DAY in the august heat! i did the install myself in two days and the material will easily pay for itself in a year! oh, and my house in in fact MUCH more comfortable! inexpensive and i highly recommend it!

[tps70124]

Two questions:

In the winter would it defeat the heat from the sun thus making one run the heater more to keep warm?

Does it shorten the life of your roof shingle?

[AtticFoil]

@tps70124 Yes and No. Since the sun is pretty low and the days are short in the winter, most areas don't get much added heat from the roof through the attic in the winter. Yes, it would actually keep this heat out. However, it also reduces heat loss in the winter by keeping heat in.

[AtticFoil]

@Xytos To be honest, you could use plain aluminum foil. The problem is that plain aluminum foil has no strength. You might be able to get it up, but one wind burst or even bird a bird in the attic would pull it down pretty quick. Thanks for the comment.

[01mustang05]

Keep the heat out. OK but where I live I spend more money in the colder days heating my home so I would imagine the sun's radiant heat would help me in the winter. Yes? No?

[AtticFoil]

@01mustang05 Radiant barrier also helps to reduce heat loss. Remember, heat always moves from hot to cold.  So, you want both r-value and low emissivity surfaces to reduce heat flowing out by conduction and radiation.