I am having a metal roof installed on my house and the roofing contractor is telling me that I should install Polaralum prior to the roof going on. We are adding a bonus room in the attic, so thwarting the heat from getting into the attic is a huge priority.

Does anybody have experience with this material installed on their house?

I understand that a radiant barrier needs air on one side of it to work, so in this application, the Polaralum is a thermal barrier.

Also, Could I put the Polaralum on the deck boards and still add a radiant barrier under the decking. It seems like the Polaralum would lesson the heat transferred to the decking, then the radiant barrier would trap it there and it could be vented.

Option 1: Install Polaralum only
Option 2: Forego Polaralum and install radiant barrier instead
Option 3: Install both the Polaralum and the radiant barrier (venting the radiant barrier air gap through the ridge vent

What option is the best?

I don't mind paying for this stuff (it is expensive), I just want my system to work and not be throwing my money away.

Thanks in advance for the replies.

My roof is a standard roof of about 10 years ago. Plywood decking, felt, shingles. I had to replace the shingles, but not the decking, so I used the polaralum as a replacement for the felt. I think the charge was about $1500 higher than just using the felt. The attic is noticibly cooler.

I don't know the proper way to install it with a metal roof, so I can't offer any special insight with your application.

Here is what I could gather from my historical electrical usage. Some periods are longer than others. They seem to range from the high 20's to the mid 30's, so one period might be 28 days, and another might be 34. It seems to be rather inexact. In addition, my A/C air handler blew up at one point and we were without the A/C for about a week in the summer and I'm not sure which month and year that happened. It appears my usage is down about 56-57 kw per period. Of course that doesn't account for the different weather patterns we've had for the last few years.


Hopefully, this helps. Best of luck.

Edited to add - The column with the red month is the most recent years usage. The final column is the difference in the two most recent year's electric usage.

If it matters, our heat runs on natural gas.

Thanks for the effort in your reply. We are weighing all options.

Parents have radiant barrier and they can't use cell phone in house / no signal because of it.

the polaralum hasn't affected our cell phone reception

I'm a huge fan of radiant barrier, but if you plan on having a room in the attic (and I'm assuming the ceiling will be high) why not just use closed cell foam up there?

The house we're in now has radiant barrier that's applied to the decking, and our attic is noticeably cooler than my parent's which doesn't have the barrier. We don't have any issues with cell reception in our house with it, but I did try to put an OTA TV antenna in the attic and got no reception. Going to a metal roof, if the cell reception is already low it will probably be an issue either way.

FWIW I took a lot of measurements of the attic temperature before/after radiant barrier and it dropped about 40 degrees in the middle of summer. Mobile reception was not affected at all.

Are you guys talking the foil radiant barrier or the spray on stuff?

My numbers are for attic foil. The manufacturer / distributor is somewhere in DFW I think.

Thanks Fife.

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Parents have radiant barrier and they can't use cell phone in house / no signal because of it.

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we have radiant barrier and do not have this problem.

www.atticfoil.com

I did mine and our attic only gets to ambient temperature. Our house is a 2 story so we don't get as much energy savings as if it was a single story with more roof area. It's been awhile, but I seem to recall that our cell quality did drop some and ended up getting a Sprint Airrave to help boost the signal.

What I was talking about is a product like this where the barrier is part of the decking board.

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What I was talking about is a product like this where the barrier is part of the decking board.

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Had this same decking installed on our roof this fall. Looking forward to seeing how much difference it really makes as our neighbor had his done a few years ago and he claims it lowered their attic temperatures by as much as 40 degrees.

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FWIW I took a lot of measurements of the attic temperature before/after radiant barrier and it dropped about 40 degrees in the middle of summer. Mobile reception was not affected at all.

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same here. I also had a tv antennae in the attic and no reception issues.

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What I was talking about is a product like this where the barrier is part of the decking board.

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this is what our house has.