Most of this is wrong. On the gable ends there is no ventilation for the hot air to escape trapped between the gable surface and the radiant barrier. The air will heat and if not ventilated it will tear out the staples. A lot of rafters do not have ventilation at the top of the roof and with heat rising there can be a pressure build up. Makes it easy to install and it can work in optimal circumstances but a lot of room for inefficiency. Optimal air gap is less than an inch.
The foil should be placed directly on the floor of the attic. That is directly on top of the ceiling, facing directly up, nothing on top. So that the heat is "reflected up". Get the aluminium foil from the kitchen section at the supermarket for $5.00 a roll. $10.00-$15.00 will probably be enough for the basic three-bedroom dwelling. Install it the way the guy in the video says? Up the rafters with the aluminium reflecting back into the attic? In a warm climate your house will be perpetually overheated.
It's the aluminium's thermal emittance rather than it's reflectivity that is the radiant barrier. If you place the foil flat on the attic floor the heat will be conducted to the ceiling of the bottom room, perhaps even more efficiently that if it were bare lol. However I suspect that the aluminium foil from the supermarker probably would be a comparable material, it's aluminium right? I'd recommend to anyone experimenting to use foil with no treatment, just plain foil. I suspect the emmisivity of the plastic would be higher.
@@blazor907 it'll work but a radiant barrier has 2 layers and air gap in between the foil. the point is to reflect heat from your shingles back out, rather than in your roof. also you want to avoid moisture buildup.
Seem like once the radiation hits the barrier it's already in the attic and will just be reflected back in to the cavity. It would need to be vented out without ability to get in to the larger attic space.
Good points. I have not tried myself but think of sun shades in a car. It is useful but still the hot air is inside the car. Therefore I assume it might work
when your attic is hot, the heat sinks into your upper floors, with the radiant barrier it reflects heat from your shingles back out rather than in your attic. your bedrooms could get 10 degrees cooler and your AC can run less.
Sorry, this is not an answer, just wondering the same thing. I plan on putting a hard foam insulation board over to enclose the foil so don't know what this hole will do? wish they explained that more
They were applying it with a 6inch air gap between the roof sheathing and the foil, which is plenty. It only needs to be 2 inches or more to reflect the infrared heat.
*It does look good, but certainly not much use for saving and retaining heat. Granted it is ideal for selling to mugs meaning gullible fools. But hopeless if you sell insulation to architects, local authorities, hospitals, or government departments. Avoid*
Reminds me of hight school videos in. Science... Would always fall asleep
I'm Impressed with this video I don't know why 🤯
Most of this is wrong. On the gable ends there is no ventilation for the hot air to escape trapped between the gable surface and the radiant barrier. The air will heat and if not ventilated it will tear out the staples.
A lot of rafters do not have ventilation at the top of the roof and with heat rising there can be a pressure build up. Makes it easy to install and it can work in optimal circumstances but a lot of room for inefficiency.
Optimal air gap is less than an inch.
What effect does it have on the temperature of the roof sheathing and shingles???
Bet they get even hotter.
6-10 degrees hotter? Well below the 200 degree limit of a shingle.
Installing Foil with no safety glasses real smart thing to do.
The foil should be placed directly on the floor of the attic. That is directly on top of the ceiling, facing directly up, nothing on top. So that the heat is "reflected up". Get the aluminium foil from the kitchen section at the supermarket for $5.00 a roll. $10.00-$15.00 will probably be enough for the basic three-bedroom dwelling. Install it the way the guy in the video says? Up the rafters with the aluminium reflecting back into the attic? In a warm climate your house will be perpetually overheated.
It's the aluminium's thermal emittance rather than it's reflectivity that is the radiant barrier. If you place the foil flat on the attic floor the heat will be conducted to the ceiling of the bottom room, perhaps even more efficiently that if it were bare lol. However I suspect that the aluminium foil from the supermarker probably would be a comparable material, it's aluminium right? I'd recommend to anyone experimenting to use foil with no treatment, just plain foil. I suspect the emmisivity of the plastic would be higher.
@@blazor907 it'll work but a radiant barrier has 2 layers and air gap in between the foil.
the point is to reflect heat from your shingles back out, rather than in your roof.
also you want to avoid moisture buildup.
What century was this filmed?.
Seem like once the radiation hits the barrier it's already in the attic and will just be reflected back in to the cavity. It would need to be vented out without ability to get in to the larger attic space.
Good points. I have not tried myself but think of sun shades in a car. It is useful but still the hot air is inside the car. Therefore I assume it might work
What’s the point….does it help with insulation?
when your attic is hot, the heat sinks into your upper floors, with the radiant barrier it reflects heat from your shingles back out rather than in your attic. your bedrooms could get 10 degrees cooler and your AC can run less.
Why don't roofers put on roof before shingles are installed?
He sounds like he should do. The news or an airplane 🛬 captain
6:52 why this gap??? Isolation is open!
Sorry, this is not an answer, just wondering the same thing. I plan on putting a hard foam insulation board over to enclose the foil so don't know what this hole will do? wish they explained that more
It needs the air gap to work. Otherwise it’ll conduct the heat instead of reflecting it.
Hot air rises.
Do the face to side to face face method then do the cha cha
Spray foam anyone, lol.
Why is this so expensive to buy.
Is it? The 2000 square foot rolls I was looking at would be about $300.
@@dyoel182 whow
Needs a air gap to be radiant. Doing it this way is just wasting your money.
They were applying it with a 6inch air gap between the roof sheathing and the foil, which is plenty. It only needs to be 2 inches or more to reflect the infrared heat.
*It does look good, but certainly not much use for saving and retaining heat. Granted it is ideal for selling to mugs meaning gullible fools. But hopeless if you sell insulation to architects, local authorities, hospitals, or government departments. Avoid*