Radiant barrier OSB?

[L5wolvesf]

I was looking at materials to do the ceiling of my garage. I had gone in thinking of using plywood, but I came across some radiant barrier OSB. The price is half of what the plywood is. The question is, is this good to use on a ceiling (foil side facing the interior of the garage) since it seems like it would help keep heat in the garage during cold months. Is there anything I should do or not do if I do this?

Thank you,
L

 

[2drx4]

Radiant barriers really don't do anything, except in a vacuum. So, I'd not bother. Unless you want a reflective ceiling.

Good quality OSB paints over nicely. It'll never looks 100% smooth, but that's the trade off for the low price.

 

[kinglake]

Radiant barriers absolutely do something. They don't help with lighting, but they very much radiate heat. I used the OSB with in a previous shop and it helped tremendously. I recommend facing the foil outside though.

If you want to see how much it works, take a sheet of OSB with the foil and point one of the electric radiant heaters at it. Hold your hand on the opposite side and time how long it takes to feel. Then do the same with normal OSB.

A radiant barrier is really meant to keep heat out in the summar by reflecting the sun's rays.

 

[bigdav160]

Radiant barriers really don't do anything, except in a vacuum. So, I'd not bother.

You're opinion is quite different than the studies done by the Florida Solar Energy Center. But I'm sure cooling isn't a problem in British Columbia.

I think it would work the way the OP wants to use it. The radiant barrier needs an air space and if turned over (facing up) it would get dirty and lose it's effectiveness.

 

[Falcon67]

I used barrier OSB on my roof. It was also used on the neighbor's house roof. Underdeck temps are a full 20F+ cooler in summer than the plain OSB on our house roof. Last time I took a breath, I was not in a vacuum.

> I recommend facing the foil outside though.
That is opposite the mfgs installation recommendations. Reflective side goes in, not out.

To the OP - doing that is fine but note that the reflective coating is very thin and is not perfect on the sheets. It's easy to damage. Also, here it's $1.50 more a sheet than plain 7/16" OSB. I would consider plain OSB with a white oil base primer coat for a nice light reflective ceiling. Locally, I can get oil base primer in 5 gallon qty for about $90 and that should cover nearly 1000 sq/ft with two coats.

I have a left over sheet of radiant - I stood it up on one wall for a while - I would not care for a ceiling full I think. JMO LOL.

 

[K'ledgeBldr]

You'll get better efficiency with d/wall and f/glass insulation than radiant barrier OSB- as you propose.
And the d/wall and f/glass will probably pay for itself down the road as oppose to...

 

[bigdav160]

You'll get better efficiency with d/wall and f/glass insulation than radiant barrier OSB- as you propose.
And the d/wall and f/glass will probably pay for itself down the road as oppose to...

Radiant barrier and insulation are two different things for two different paths of heat transfer.

They shouldn't be confused.

If the OP doesn't install climate control how does the insulation "pay for itself down the road"?

 

[K'ledgeBldr]

...it seems like it would help keep heat in the garage during cold months. Is there anything I should do or not do if I do this?

Thank you,
L

See this quote? I'm not confused at all- but the OP apparently is.

Radiant barrier and insulation are two different things for two different paths of heat transfer.
Heat transfer?
They shouldn't be confused.

If the OP doesn't install climate control how does the insulation "pay for itself down the road"?

From the quote above I believe it would be fair to assume that there is a 'heat source'.

 

[Socal 610]

I installed this material in my(Hot Desert) house, worth every penny. Foil down always.

 

[Falcon67]

>since it seems like it would help keep heat in the garage during cold months.

No, doesn't work like that. It helps reduce attic temps, which can reduce the heat load on the building. My new shop is just a building shell and the radiant actually reduces the heat gain I'd normally get on cold days with sun. I can warm the place faster by opening the south facing 16' door to let the sun heat the concrete. Couple of hours warms it by 10F at least, maybe more. It was low 40s this morning and will be 70s this afternoon. When I go home, it'll be maybe 60 something in there.

You will also want to be sure and construct good attic ventilation. I used eve vents (not installed yet) and regular "cut a hole" roof vents. Two 4"x12" eve vents and one 10" upper vent for every 8' of roof length on mine.

 

[L5wolvesf]

The garage (concrete block walls) has a heat source, wood stove – mesquite to be more precise. My aim is to keep heat in during cold months. My thought is the radiant barrier, foil facing down toward the interior of the garage, will help keep heat in. There seems to be differing opinions on the direction it should face. I would think the foil would keep some heat from passing through into the attic space. Facing up (toward the attic space) not so much - and like bigdav160 said “it would get dirty and lose it's effectiveness”.

As a follow up question I was going to ask if I should used paper backed f’glass batt insulation above the OSB (I have some left over from doing the house). Or if I should use f’glass batts without paper.

I am less concerned about what it would look like, but Falcon67’s idea is something I will consider.

Thank you,
L

 

[bigdav160]

See this quote? I'm not confused at all- but the OP apparently is.

Sorry, my reading skills are getting worse. Perhaps I need an eye doctor.

L, you need insulation to hold the heat in.

 

[brokenknee]

The garage (concrete block walls) has a heat source, wood stove – mesquite to be more precise. My aim is to keep heat in during cold months. My thought is the radiant barrier, foil facing down toward the interior of the garage, will help keep heat in. There seems to be differing opinions on the direction it should face. I would think the foil would keep some heat from passing through into the attic space. Facing up (toward the attic space) not so much - and like bigdav160 said “it would get dirty and lose it's effectiveness”.

As a follow up question I was going to ask if I should used paper backed f’glass batt insulation above the OSB (I have some left over from doing the house). Or if I should use f’glass batts without paper.

I am less concerned about what it would look like, but Falcon67’s idea is something I will consider.

Thank you,
L

you should have a vapor barrier, either paper or plastic sheathing is fine. I prefer the plastic. Vapor barrier on the warm side.

 

[2drx4]

I stand by my comment that the radiant barrier will be largely useless, especially given what the OP wants to do.

I had considered using it as an insulation, so I decided to do a little reading. I read through a lot of the links on this page:

http://www.healthyheating.com/Page 55/Page_55_o_bldg_sys.htm

It has it's uses, yes, but it will be ineffective installed as a ceiling in a shop. Especially when it comes to trying to keep the heat in.

Spend a couple bucks more and buy some fiberglass or roxul batts and put them above the ceiling (in the attic). Stick some poly film up before you put whatever ceiling on. And vent the attic. Or do any of the other conventional/proven methods of insulating against cold (spray foam, blown in cellulose, rigid foam, etc).

Not trying to sound like an ***, but I come off that way sometimes