Radiant Barrier in attic (Deport: houses, neighborhood, roofing)

[LastStraw]

We're wanting to do something about the heat coming in the house and are thinking about maybe adding Radiant Barrier or something similar in the attic. We would like to add Ridge Vents but the roofing company said they are out of the question because of the design of our roof.
I've also heard about putting something similar to radiant barrier on the inside of the garage door.

If anyone has had recent experience doing this sort of thing I would really appreciate opinions and possibly some recommendations of what company to use to do the job. I don't mean just for the garage doors, but the attic as well.
TIA

[bigtexan99]

I know a guy that does radiant barrier for under $4 a foot. I'll PM you his details tonight.

[TrapperL]

Radiant barriers are worth their weight in gold. There are different types. One is a foil faced decking material. On existing houses that would mean tearing the roof down to the rafters and replacing the roof decking. Then there is the spray on type. It sprays on like a paint. It requires some knowledge of the material as it can be put on too thick and it destroys the value of it. A proper job will have the attic white but you can still see the wood grain thru it. I've been in attics where the outside temp was over 100F yet the attic temp was just in the 90's, it makes that much of a difference. It's like owning a home that is completely under trees. Adding more vents buys you nothing as the heat source, radiant heat, isn't being stopped. If you were to laser temp probe the insulation, it remains hot even with power vents installed. Put a radiant barrier in and insulation temps fall dramatically, as much as 40F which eliminates conductive heat. In this area, radiant barriers should be a requirement, not an option. It might surprise you to know it also helps with winter heating too. It works by reflecting the heat back into the home. Look at it as an item that reflects heat regardless of where it comes from. I'd suggest researching the spray on materials as they are not all the same. Some are better than others but any at all is great. I won't suggest an installer but I'd avoid the ones that advertise they will spray it on and include an insulation upgrade free. Nothing in the building trades is free. All they're doing is draining your wallet. Check with insulation companies around town and get several prices. Obviously, depending on the size of the attic, an average house will run somewhere just under a grand for spray.
Depending on the garage doors, there are doors that have insulation panels available. They are made specifically for that size and brand door. Might check with Overhead Door Company and ask them about it.

[geargrinder70]

LastStraw, I found a garage door insulation kit by Owens Corning at Home Deport which was very easy to put up on the inside of the door. It made a big difference in the garage temp during the day.

[markintosh]

Originally Posted by TrapperL

Radiant barriers are worth their weight in gold...

Trapper, is this the same as the "spray-on foam" method that you sometimes see advertised? This is sprayed/applied directly to the underside of the roof decking, correct? Our house is older and I can see the roofing nails in some spots coming through the decking... I'm assuming that in the future when we re-roof, this underside would need to be touched up?

Thanks!

[TrapperL]

Trapper, is this the same as the "spray-on foam" method that you sometimes see advertised?

No, the radiant barrier is a ceramic crystal paint and looks like paint that's been put on too thin. That's the correct way for it to look.

BigTexan99, kindly PM me yer buds info as well. I can always use good subs especially for the existing home market.

[LastStraw]

Thanks....I appreciate all the information.
"bigtexan99" .... I look forward to receiving the PM with the name of the person that does it.

Several days ago, I saw some installers parked at a house in my neighborhood and it looked like they were putting in insulation, so I stopped and asked them. .. The guy said yes,.. so I asked for his business card and told him we were interested in doing something like that too.
He said they were installing both Radiant Barrier and Blow-in Insulation in that particular house they were working on.
I told him I was more interested in the Radiant Barrier, since our house already has insulation. He told me they staple the Radiant Barrier in and he showed me a small 4" x 5" sample. I was surprised because it was very thin and flimsy,.. almost like a piece of paper. Not what I expected at all.
His business card has the website on it and explains the installation methods are either "Lay-Over" or "Staple-Up". The Staple-up installation is perfect for those who have the HVAC unit and duct work in the attic. It is stapled-up against the roof rafters. Since we have our HVAC unit and duct work in the attic, I guess Staple-up would be the option for us.
It was also on the website that I saw about the Garage door being done too.
I don't know if I am allowed to mention the name of that business or give their website.


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[bigtexan99]

PM's sent.

Radiant barrier is basically just a thin foil. The staple up method creates an air pocket between it and the inside of your roof. The heat then travels up this air pocket and out the ridge vent.

It's literally stapled onto the rafters. If you are agile and have a staple gun, its tedious but easy work in the winter.

The lay over method is not as popular since its just laid over the existing insulation on your attic floor. The heat stays in the attic and like you said, with the duct work there its just more heat for the ductwork.

Stapled to the rafters and with a ridge vent installed is the way to go. Some say that this new radiant hot air pocket 'cooks' your shingles as they get hotter than before. I don't have any hard data on that.

[dpantle]

Originally Posted by bigtexan99

Some say that this new radiant hot air pocket 'cooks' your shingles as they get hotter than before. I don't have any hard data on that.

It seems to me that there wouldn't be a difference than not having it, provided you are vented the same. I would think the temp in the pocket would be similar than if no pocket at all.

I've got a roof that's 25'+ higher than my attic floor, so this method appeals to me. Anyone out there with this method of Radiant Barrier? Any pro's or con's either way?

[LastStraw]

Originally Posted by bigtexan99

PM's sent.

I haven't received a PM from you ???



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