It reflects, infrared, not ultraviolet. There is no ultraviolet that makes it through a typical roof; it does not need to block ultraviolet. For proof, if ultraviolet made it through a typical roof, everything under the roof would be sun faded. for this reason, things that are used outdoors are what they call, UV stable.
Yeah, that was physically painful to watch. I thought it was an honest mistake the first time he said it, but then he just kept repeating it to the point I started wincing as he said it.
@@whatthefunction9140Oddly enough, my infant seems to have gotten a tan through the roof. He barely goes outside but he’s quite tan. Me and my wife are both really pale, so it’s gotta be a tan.
I had to reroof in GA a few years ago - unconditioned attic. My GC could only source 7/16" OSB with radiant barrier ( I went with a thicker OSB) so I had him lay the thin foil type barrier down on the rafters before laying the new sheathing. With 24" rafter spacing I'm only loosing 6% effectiveness, where the rafter touches the radiant barrier and renders it useless. The difference was before I could only stay in the attic for 10 minutes during the summer, to being able to be up there continuously (yet uncomfortably hot). Regardless of how well your attic floor is insulated, a 140 degree attic will transfer more heat to the 72 degree rooms below than a 110 degree attic - higher temperature differentials cause heat to transfer faster in one direction, given any R-value.
It works if installed with air gap! I would highly suggest using radiant barrier OSB over skip sheathing as well. (Over an exsiting shake tear off /conversion ) It will still provide half the value as if it was installed direct over rafters.
Why do all the videos show the Sharkskin layer down and the other layer of Sharkskin with foil over that, wouldn't it be more economical to put down Sharkskin with radiant first with foil facing up then just put battens over that for the air space?
Good info I am in central FL. will need new roof next year or following. Was considering radiant barrier in attic makes since to put on roof when doing new roof.😄
Thank you for taking the time to create this channel and the content on it. It’s been helpful. Do you have any standard details, showing the assemblies discussed in this video? If using an air gap, similar as Matt R. with battens on top of the sheathing, how is the low side vented with a standing seam metal roof? I can see how the ridge is vented, but how are you getting the air moving on top of the sheathing up through the ridge? I’m in South Florida, so need to see some details to see if this can work for me
Thanks for the kind words! There is typically some kind of venting material behind the eave metal or perforated soffit for the air to enter the assembly. If you're in Florida, you definitely want to check on your engineering and code requirements before making any decisions. -Thad
What about putting Styrofoam boards in between the 1x4 boards and screwing down the metal roof down onto that? I know that it will reduce the air gap but, you are gaining a layer of insulation. Maybe use one of the boards that has foil on one side?
The air gap is actually superior to insulation as it has some venting properties. Air is a great insulator as well. I think you’d be better off keeping that gap and adding more blown in insulation to the attic floor. Alternatively, you could use something like Reflectix in the attic across the bottom of the trusses to give you another radiant barrier.
Aluminiu is a very good heat conductor too. It deal's the radiation heat but it s exposé on conduction heat. Does anyone make a real test to see a win lose scenario?
Hit the send button too soon.... My question is, I have an existing steel clad (roof and sides) building. Vaulted pitch with blowen in insulation and continus ridge venting. I live in a dry Denver like climate. My summer heat ventilation flows up the walls (between metal siding and insulation. Then over the top of my insulation and out the ridge vents. My 2 questions are, can I lay the radiant barrier on top of my blowen in insulation? Also if I do that it sounds like it should be shinny side up to create the air space? Thanks again for your great video and advice!! Jim at 4800 feet in the mostly snowy dry partl of Oregon
Actually aluminum will reflect the majority of the em range of frequencies, depending on how thick of a deposit is made on the underlying plastic film, from microwave through infrared through visible to most of the ultraviolet. Not all bands will reflect back into space, especially the infrared and parts of the uv. What bands do make it back out to space is most of the visible and a fair part of the microwave frequencies. Overall it’s significantly better nothing. The air gap Carrie’s of the ir that radiates from the inner and the underside of the outer layer through convection, transferring that energy directly from the surface of the inner layers.
At :54 secs in he states that it's to reflect "ultraviolet ... radiation" back to space, and repeatedly says so. Are you sure it's ultraviolet? Because infrared is heat specifically, not UV.
would any radiant thermal break work? does it have to be air? i used a rubber tape i got super cheap, (for adhering a template to a commercial printer roll), on the walls of campervan. idea was as a thermal break for aluminium sheet. the sheet is for radiant reflection, what about the air gap for radiant heat now? is it a thing?
The topic is not about skin cancer, suntan or furniture upholstery fading… Solar heat gain in buildings has nothing to do with UV radiation. Heat is carried from Sun by infrared IR radiation. Otherwise good presentation
The bigger the air gap, the better effect you’re going to get. The manufacturers of radiant barriers always do their testing with 1” of air space. The more space you can get the better.
No matter how you install this you’ll have a few places in contact, how else would you hold it in place?? I would think the rain screen would be a good air gap
You’re going to get the biggest benefit from this on whichever side has the biggest air gap and the most ventilation. In most cases, that’s the attic. Reflectix and a few other companies sell a product that can be stapled to your trusses fairly easily. I did 1500sqft of it in a few hours. At a certain point, you’re splitting hairs with this stuff too. A much bigger impact is going to be found by ensuring your attic has enough ventilation and maybe even adding more ventilation than the 1sqft of NFA for every 150sqft of attic space that’s typically recommended.
I hear there's a huge difference in using the radiant barrier created by "AtticFoil" compared to all the others. I heard that the quality of the sheets created by "AtticFoil" are far more superior than all the rest of the other radiant barriers out there. Again, it's just what I've heard.
Yeah, it’s a tough product. It’s designed to be added after the fact, so it needs to hold up to people bumping their head on it, grabbing it for support if the lose their balance, stacking storage containers against it, etc. Radiant barriers that are glued to OSB don’t really need to be that tough.
@@kungfoochicken08 I'd just rather stick to atticfoil, with this product you know you are getting your money's worth and you know it's going to last a lot longer than the others. cause most things made these days are purposely made to be flimsy and weak and definitely made to not last very long, and that's not by accident, that is done on purpose by design so that company's know they will have a returning customer to buy more products. Every business revenue is made by when customers return to the store to purchase more. What better way to keep themselves in business, making products that are purposely not built to last. That goes for everything you can think of. Remember that saying, "they don't make them like they use to" that's all on purpose.
I'm in South Central Texas, between San Antonio and Austin. I have an OSB roof deck with a foil radiant barrier facing the attic. The roof is standing seam galv-alum steel. Now that I have no air gap between the radiant barrier and the roof deck, what do you suggest I do? The home was built 7 years ago with this roof. The builder is also an architect! Was this roof / radiant barrier system the accepted practice in 2016? Thanks, Barry
That’s the proper application. The air gap is the attic space. Radiant barriers work because aluminum isn’t very good at emitting heat. It will absorb the heat from the roof deck, but it’s not going to emit most of it. Where you run into problems is if the radiant barrier didn’t have an air gap on either side. The material on either side would absorb the heat from the aluminum through conduction. If you really want to overkill this, you can get a product called Reflectix and add another radiant barrier underneath your trusses. It’s about 25 cents a square foot and you simply staple it to the underside of the truss. I did my 1500sqft house in about 2 hours. There’s a bunch of videos online. Reflectix claims you can get R-21 from two layers of radiant barrier, but that might be a stretch. I only used the one layer of radiant barrier and noticed a 20 degree drop in my attic.
@@kungfoochicken08 Thanks for the education on radiant barriers. Did your Attic already have a radiant barrier BEFORE you added the reflectex? I wouldn't expect a 20° drop in Attic temp. It's already WAY Cooler than the house I had before without any radient barrier.
@@barrylitchfield8357 There wasn’t a radiant barrier before I added the Reflectix. I got about a 20 degree drop from the Reflectix and another 10 degree drop from doubling my ventilation. I went from 1500 square inches of NFA to 3000 in a 1500sqft house. I think ventilation is going to be your biggest bang for your buck, even before adding the first layer of radiant barrier. A radiant barrier is fairly cheap. I got the 4’ by 100’ roll of Reflectix from Lowe’s. For $500 I did my whole attic, leaving a gap at the top and bottom for venting, and adding another layer over my ductwork using styrofoam as a spacer. If you’re looking to cool your house down, the first place to look is your venting though. Check your soffits and make sure you have at least 72 sq inches of soffit venting for every 150sqft of attic space. Most people have vinyl soffit vents and those are 12 inches of NFA per square foot.
@@kungfoochicken08 Thanks for the venting information. This house is 9 years old, and the Attic is the coolest one I've ever been inside of in summer heat in south Texas. Ridge vents and soffit vents were included when the house was built, as well as the foil backed roof deck. The builder is an architect, and he builds good homes.
@@barrylitchfield8357 That’s great. It seems like you’ve already got all the low-hanging fruit. You could bump up to R-60 insulation or add a product like Reflectix or AtticFoil to create another radiant barrier. If you’re doing the work yourself, both of those will still take 10-15 years for you to get your money back out of them if your attic is already vented well and insulated.
What a long and droning video., You made the video for roofing nerds, not people wanting to learn. 10 minutes and I have had to fast forward 20 times.. Still haven't gotten to the meat of the information. I gave up at 18 minutes. So this won't help me insulate my existing attic. It must be installed under the metal roof with some plastic panels to jack it up a little to have an air gap. And evidently it won't help installing it in the floor joists.
It reflects, infrared, not ultraviolet. There is no ultraviolet that makes it through a typical roof; it does not need to block ultraviolet. For proof, if ultraviolet made it through a typical roof, everything under the roof would be sun faded. for this reason, things that are used outdoors are what they call, UV stable.
IR not uv...
That guy... what a joke he destroyed the whole thing 😂
Absolutely IR not UV 😂
@@voramuj if you get a tan through your roof there's a problem
Yeah, that was physically painful to watch. I thought it was an honest mistake the first time he said it, but then he just kept repeating it to the point I started wincing as he said it.
@@whatthefunction9140Oddly enough, my infant seems to have gotten a tan through the roof. He barely goes outside but he’s quite tan. Me and my wife are both really pale, so it’s gotta be a tan.
While experimenting, I found silver reflecting on both sides works best, reflects heat out while keeping a more constant temp inside.
Great panel of guest with good information! Thank you.
I had to reroof in GA a few years ago - unconditioned attic. My GC could only source 7/16" OSB with radiant barrier ( I went with a thicker OSB) so I had him lay the thin foil type barrier down on the rafters before laying the new sheathing. With 24" rafter spacing I'm only loosing 6% effectiveness, where the rafter touches the radiant barrier and renders it useless. The difference was before I could only stay in the attic for 10 minutes during the summer, to being able to be up there continuously (yet uncomfortably hot). Regardless of how well your attic floor is insulated, a 140 degree attic will transfer more heat to the 72 degree rooms below than a 110 degree attic - higher temperature differentials cause heat to transfer faster in one direction, given any R-value.
It works if installed with air gap! I would highly suggest using radiant barrier OSB over skip sheathing as well. (Over an exsiting shake tear off /conversion ) It will still provide half the value as if it was installed direct over rafters.
Good comment. Explaining why the air gap is required is a full time job at www.RoofingFoil.com
What?
Come on… Talking about UV instead of IR doesn’t give me confidence in the claimed but not proven efficiency of the barrier !
What if it is double sided reflected
Props to calling out Matt with the Build show 👍🏻
Thanks for giving us an educated view on radiant Barriers that is unbiased. :):)
Why do all the videos show the Sharkskin layer down and the other layer of Sharkskin with foil over that, wouldn't it be more economical to put down Sharkskin with radiant first with foil facing up then just put battens over that for the air space?
Can you make a video on how to install radiant barrier and roll on insulation? Which one goes on first and the detail steps to it.
Love the titles! Very creative and they look great. Good content. Thank you!
Thanks for watching! -Thad
So, after all that, does the shiny side go up or down???????
To the side with gap/air. Thus, facing toward the attic side in most roofing system.
Thanks guys.
Good info I am in central FL. will need new roof next year or following. Was considering radiant barrier in attic makes since to put on roof when doing new roof.😄
Thank you for taking the time to create this channel and the content on it. It’s been helpful.
Do you have any standard details, showing the assemblies discussed in this video?
If using an air gap, similar as Matt R. with battens on top of the sheathing, how is the low side vented with a standing seam metal roof? I can see how the ridge is vented, but how are you getting the air moving on top of the sheathing up through the ridge?
I’m in South Florida, so need to see some details to see if this can work for me
Thanks for the kind words! There is typically some kind of venting material behind the eave metal or perforated soffit for the air to enter the assembly. If you're in Florida, you definitely want to check on your engineering and code requirements before making any decisions. -Thad
What about putting Styrofoam boards in between the 1x4 boards and screwing down the metal roof down onto that? I know that it will reduce the air gap but, you are gaining a layer of insulation. Maybe use one of the boards that has foil on one side?
The air gap is actually superior to insulation as it has some venting properties. Air is a great insulator as well.
I think you’d be better off keeping that gap and adding more blown in insulation to the attic floor. Alternatively, you could use something like Reflectix in the attic across the bottom of the trusses to give you another radiant barrier.
Ultraviolet? I would say that is infrared what reflects. UV can't pass through tiles or any roofing cover.
Aluminiu is a very good heat conductor too. It deal's the radiation heat but it s exposé on conduction heat. Does anyone make a real test to see a win lose scenario?
Hey great informative video! So thanks
Hit the send button too soon....
My question is, I have an existing steel clad (roof and sides) building. Vaulted pitch with blowen in insulation and continus ridge venting. I live in a dry Denver like climate. My summer heat ventilation flows up the walls (between metal siding and insulation. Then over the top of my insulation and out the ridge vents.
My 2 questions are, can I lay the radiant barrier on top of my blowen in insulation?
Also if I do that it sounds like it should be shinny side up to create the air space?
Thanks again for your great video and advice!!
Jim at 4800 feet in the mostly snowy dry partl of Oregon
Actually aluminum will reflect the majority of the em range of frequencies, depending on how thick of a deposit is made on the underlying plastic film, from microwave through infrared through visible to most of the ultraviolet. Not all bands will reflect back into space, especially the infrared and parts of the uv. What bands do make it back out to space is most of the visible and a fair part of the microwave frequencies. Overall it’s significantly better nothing. The air gap Carrie’s of the ir that radiates from the inner and the underside of the outer layer through convection, transferring that energy directly from the surface of the inner layers.
At :54 secs in he states that it's to reflect "ultraviolet ... radiation" back to space, and repeatedly says so. Are you sure it's ultraviolet? Because infrared is heat specifically, not UV.
I caught that too - you are correct
would any radiant thermal break work? does it have to be air? i used a rubber tape i got super cheap, (for adhering a template to a commercial printer roll), on the walls of campervan.
idea was as a thermal break for aluminium sheet.
the sheet is for radiant reflection, what about the air gap for radiant heat now? is it a thing?
The topic is not about skin cancer, suntan or furniture upholstery fading…
Solar heat gain in buildings has nothing to do with UV radiation. Heat is carried from Sun by infrared IR radiation.
Otherwise good presentation
how much air gap is required between the barrier and the metal roof?
Judging by that black mat 1/4 inch.
The bigger the air gap, the better effect you’re going to get. The manufacturers of radiant barriers always do their testing with 1” of air space. The more space you can get the better.
What if you face it up on your roof but have a rain screen? You would have a gap but there are points where you don’t along the wood strips?
No matter how you install this you’ll have a few places in contact, how else would you hold it in place?? I would think the rain screen would be a good air gap
You’re going to get the biggest benefit from this on whichever side has the biggest air gap and the most ventilation. In most cases, that’s the attic.
Reflectix and a few other companies sell a product that can be stapled to your trusses fairly easily. I did 1500sqft of it in a few hours.
At a certain point, you’re splitting hairs with this stuff too. A much bigger impact is going to be found by ensuring your attic has enough ventilation and maybe even adding more ventilation than the 1sqft of NFA for every 150sqft of attic space that’s typically recommended.
I hear there's a huge difference in using the radiant barrier created by "AtticFoil" compared to all the others. I heard that the quality of the sheets created by "AtticFoil" are far more superior than all the rest of the other radiant barriers out there. Again, it's just what I've heard.
Yeah, it’s a tough product. It’s designed to be added after the fact, so it needs to hold up to people bumping their head on it, grabbing it for support if the lose their balance, stacking storage containers against it, etc. Radiant barriers that are glued to OSB don’t really need to be that tough.
@@kungfoochicken08 I'd just rather stick to atticfoil, with this product you know you are getting your money's worth and you know it's going to last a lot longer than the others. cause most things made these days are purposely made to be flimsy and weak and definitely made to not last very long, and that's not by accident, that is done on purpose by design so that company's know they will have a returning customer to buy more products. Every business revenue is made by when customers return to the store to purchase more. What better way to keep themselves in business, making products that are purposely not built to last. That goes for everything you can think of. Remember that saying, "they don't make them like they use to" that's all on purpose.
Sharkskin guy keeps saying UV, I think he means IR.
What about peel and stick rubber? To make a second wet membrane.
I'm in South Central Texas, between San Antonio and Austin. I have an OSB roof deck with a foil radiant barrier facing the attic. The roof is standing seam galv-alum steel. Now that I have no air gap between the radiant barrier and the roof deck, what do you suggest I do? The home was built 7 years ago with this roof. The builder is also an architect! Was this roof / radiant barrier system the accepted practice in 2016? Thanks, Barry
That’s the proper application. The air gap is the attic space. Radiant barriers work because aluminum isn’t very good at emitting heat. It will absorb the heat from the roof deck, but it’s not going to emit most of it.
Where you run into problems is if the radiant barrier didn’t have an air gap on either side. The material on either side would absorb the heat from the aluminum through conduction.
If you really want to overkill this, you can get a product called Reflectix and add another radiant barrier underneath your trusses. It’s about 25 cents a square foot and you simply staple it to the underside of the truss. I did my 1500sqft house in about 2 hours. There’s a bunch of videos online. Reflectix claims you can get R-21 from two layers of radiant barrier, but that might be a stretch.
I only used the one layer of radiant barrier and noticed a 20 degree drop in my attic.
@@kungfoochicken08 Thanks for the education on radiant barriers. Did your Attic already have a radiant barrier BEFORE you added the reflectex?
I wouldn't expect a 20° drop in Attic temp. It's already WAY Cooler than the house I had before without any radient barrier.
@@barrylitchfield8357 There wasn’t a radiant barrier before I added the Reflectix. I got about a 20 degree drop from the Reflectix and another 10 degree drop from doubling my ventilation. I went from 1500 square inches of NFA to 3000 in a 1500sqft house. I think ventilation is going to be your biggest bang for your buck, even before adding the first layer of radiant barrier.
A radiant barrier is fairly cheap. I got the 4’ by 100’ roll of Reflectix from Lowe’s. For $500 I did my whole attic, leaving a gap at the top and bottom for venting, and adding another layer over my ductwork using styrofoam as a spacer.
If you’re looking to cool your house down, the first place to look is your venting though. Check your soffits and make sure you have at least 72 sq inches of soffit venting for every 150sqft of attic space. Most people have vinyl soffit vents and those are 12 inches of NFA per square foot.
@@kungfoochicken08 Thanks for the venting information. This house is 9 years old, and the Attic is the coolest one I've ever been inside of in summer heat in south Texas. Ridge vents and soffit vents were included when the house was built, as well as the foil backed roof deck. The builder is an architect, and he builds good homes.
@@barrylitchfield8357 That’s great. It seems like you’ve already got all the low-hanging fruit. You could bump up to R-60 insulation or add a product like Reflectix or AtticFoil to create another radiant barrier. If you’re doing the work yourself, both of those will still take 10-15 years for you to get your money back out of them if your attic is already vented well and insulated.
5 to 10% energy savings is not much. About $20/month for something that cost $thousands to install.
How much does the radiant barriers cost.
Check out www.AtticFoil.com and www.RoofingFoil.com pricing is on websites.
Uv huh. Lol
😂😂guess they don't even able to tell uv and ir differences..
What a long and droning video., You made the video for roofing nerds, not people wanting to learn. 10 minutes and I have had to fast forward 20 times.. Still haven't gotten to the meat of the information.
I gave up at 18 minutes. So this won't help me insulate my existing attic. It must be installed under the metal roof with some plastic panels to jack it up a little to have an air gap.
And evidently it won't help installing it in the floor joists.