Yeah, I had to research that as well. The roof temp is only raised by 5 to 10 degrees, which is easily within the roof specs. Also, by installing it on the rafters, you prevent the dust from getting on it (unlike installing it on the floorboards).
Installing a radiant barrier as shown above will cook the roof deck, the shingles and signficantly lower the life of any roofing system...unless it's steel. Further, once dust settles on the top surface the effect of the reflecting of infrared heat is reduced signficantly.
I'm in Dallas, so my recommendation has always been Ventilate, Insulate, Radiant Barrier. I say that, because half of the houses that i crawled up in the attic, barely covered the 2x4 (yes, the cheaper homes use 2x4 rather than 2x6 or 2x8 for the attic floor). Radiant Barrier is awesome at keeping heat out, but without the insulation, you immediately lose the AC you are blowing around inside the house. If you have decent insulation, that's when the barrier is the next step.
Also, if the objective is to keep heat from coming in from the roof line where the suns radiant heat transfers in, the insulation Batts will not effect this, and it would still be counterproductive in keeping the place warmer during the colder seasons, and still blocking the radiant heat in the summer..
additional insulation is always good, but its also more expensive. you can get 500sqft of foil for about $70. If you are going to add extra insulation, the blow in cellulose is cheaper and easier to add as opposed to putting batts on the roof.
thats not the way we install it in the northeat. we install it in between the rafters. the foil has layers that can't be stapled.
TheMark76ers 5 months ago
Yeah, I had to research that as well. The roof temp is only raised by 5 to 10 degrees, which is easily within the roof specs. Also, by installing it on the rafters, you prevent the dust from getting on it (unlike installing it on the floorboards).
peddlewin 1 year ago
Installing a radiant barrier as shown above will cook the roof deck, the shingles and signficantly lower the life of any roofing system...unless it's steel. Further, once dust settles on the top surface the effect of the reflecting of infrared heat is reduced signficantly.
nrgsaver 1 year ago
I know what it cost... Im an been in the insulation trade for over 10 years as an installer..
faithsno1dad 1 year ago
@faithsno1dad
I'm in Dallas, so my recommendation has always been Ventilate, Insulate, Radiant Barrier. I say that, because half of the houses that i crawled up in the attic, barely covered the 2x4 (yes, the cheaper homes use 2x4 rather than 2x6 or 2x8 for the attic floor). Radiant Barrier is awesome at keeping heat out, but without the insulation, you immediately lose the AC you are blowing around inside the house. If you have decent insulation, that's when the barrier is the next step.
peddlewin 1 year ago
Also, if the objective is to keep heat from coming in from the roof line where the suns radiant heat transfers in, the insulation Batts will not effect this, and it would still be counterproductive in keeping the place warmer during the colder seasons, and still blocking the radiant heat in the summer..
faithsno1dad 1 year ago
I would recommend also add some Un-face crafted batts first, then applying the foil.
Even if it is a none heated space, the add insulation behind, with the foil face will do a stellar job.
faithsno1dad 1 year ago
additional insulation is always good, but its also more expensive. you can get 500sqft of foil for about $70. If you are going to add extra insulation, the blow in cellulose is cheaper and easier to add as opposed to putting batts on the roof.
peddlewin 1 year ago