I am going to install a radiant barrier in my house. Is it best to install it on the floor or ceiling and why?
Question:There are many websites out there that tell you what is the best way to install it. Some want you to install it BETWEEN your roof support joists. Some want you to install it ON TOP of your wood joists. Some say that you should just put a layer down on top of your existing insulation and not even worry about putting it on your roof joists. Does someone have any idea what works best?? They all appear to work WELL, but if I'm spending the $400 to put it on the house, then I might as well do it right. Thanks.
Answers:
Dave S. is correct. You can't put it on to of your roof support joist (rafters) without taking off the roof deck. The barrier is designed to send radiant heat back out of your attic so the closer to the heat source the better. Most I've seen tell you to it against the attic side of your roof deck. Either horizontally between the rafters, which will require some cutting, or vertically going up and down over the rafters. I hope you have a attic that has lots of room to maneuver. It is very difficult to get it down close to the ceiling joist since you run out of room to move. There is a down side to the barrier. Since it bounces the radiant energy back through your roof it can build up a lot of heat for the roof and cook your shingles.
This would be especially bad in high heat areas. Another approach would be spend the money on better ventilation for your attic. Ridge vents work very well since heat rises to the highest point in you attic. They lowered the temperature of my attic close to outside air temp. I installed the ridge vents and then cut a large hole in the sheetrock over my washer/dryer and put 1/8" mesh hardware cloth over the hole. I framed it with moulding for aesthetics. As the heat rises it needs to be able to draw air from somewhere to leave the attic, so the more air the better. So do some more reading and ask your building supply people to see if what you are about to do is cost effecient. Good luck!
It just needs to be there to do its thing, I would install it in the way that is easiest.
You may be getting information mixed up between new construction methods and already built houses methods.
If you think is more important, then you should sidestep the websites and make a few phonecalls, otherwise you will just get
confusing opinions.
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