OSB w/ Foil Radiant Barrier

[karoc]

Guys before I pull trigger for this OSB with radiant barrier for my shop area, I was wondering if it’s worth the extra cost? Here in Texas, a shop with metal would be like oven. My plan is radiant barrier for roof decking and insulation for walls, and have ventilation. Shop not going to be condition space, so going try make it as comfortable as possible without adding AC. I just don’t think that open ceil spray foam is in my budget. Looking for opinions

 

[Hank11]

The ceiling is by far the best return for insulation money.

 

[duneslider]

The osb with the foil is NOT better than insulation. It has a little benefit but not much.

 

[dcg9381]

My understanding and I'm in your state:

OSB + reflective coating - this is an excellent reflective barrier, but to be effective, you need an air gap between the radiant barrier and insulation. Traditional "attic" design allows for this gap, as the attic is the air gap and typically has vents.

A metal shop is not like an oven any more than an uninsulated stick and brick house is an oven. It's all about how you insulate it and how reflective you can make the roof. IMHO, a highly reflective steel roof is superior to a composite roof, OSB, and a radiant barrier.

Shop not going to be condition space, so going try make it as comfortable as possible without adding AC.

Dude, you're in Texas. You're gonna fry without AC. Even if you build Yeti cooler to R40. It's just about "how long does it take" to reach ambient temps. Maybe you can survive in the evenings if you can move air through the building... I'm just getting to be an old man.

What's your building design? Size, height, etc?

Spray foam is expensive. Absolutely. But you can do some "budget" combo of insulation like 2-3 inches on the roof deck, insulate the walls with bat yourself, and then over-HVAC a bit (inverter/ductless) and you'll have a structure you can live in. Even if you can't write a check for it now, design for it so you can slowly add...

 

[Hank11]

Its gonna be an oven without insulation.
Insulate the ceiling and as much as you can in the walls.

 

[428PI]

Haven't any of you guys felt the radiant heat coming through the side metal walls when the sun hits it?

 

[readhead]

I use it on all of my sheds as a standard feature. When I first started using it I had sheds that didn’t have it and it was about 8-10 degrees cooler in the new ones. I think it is well worth the money.

 

[CamMark]

In my neck of the woods (with climate similar to east TX) the price difference to have the radiant barrier OSB was about $1.50/sheet. That works out to about $50 extra in total for my project so I decided to use it. If it makes even a small difference I will consider it worthwhile.

Though I do have insulation, good ventilation and full shade on the wall with the most solar gain. But no A/C (yet!). Only time will tell if that's good enough for my comfort goal.

 

[ycgoat]

I put up foil only on the ceiling in my un insulated metal building, in the Mid Atlantic region and the interior temps stay ambient. The foil is reflective on both sides and has air gaps on both sides since there is no paneling. I can not speak on the OSB.

 

[karoc]

Thanks for responding and opinions, it’s all stick build with 12 ceiling height using trusses. Wasn’t planning on putting ceiling in, but if I did I would try get metal panels with perforated holes. I was told that can expect about 30* temperature difference with OSB foil barrier. In my area it’s about 10.00 more sheet vs OSB without foil, which I need 60 sheets. I really like to insulate it as Cathedral ceiling. But going to get price just for giggles grins for OC spray foam

 

[bluedog225]

100% worth it.

Must have a gap. Must have a gap. Min 3/4 inch. On either side. Otherwise it’s wasted money.

Gap on “sun” side is highly reflective. Gap in the inside is low emissivity. Two different phenomena. Aluminum is great at reflecting heat, and great at not emitting heat. On the order of 97-99%. That is, a hot piece of aluminum will not radiate the heat to a nearby surface.

You can also paint your roof with Henry’s “cool roof” elastomeric paint. Really cools off the roof. To the point you can put your hand on it when it’s 110 eff.

 

[My Old Tools]

Insulate the roof if you don't want a ceiling/attic. I did 12 inches on mine vs the 4" on the previous shop. Huge difference. Also, the MrCool is worth the money in Texas.

 

[aqr81]

I built a faily large shop in Bakersfield, Ca for my son finishing last year. Bakersfield is much like Texas in terms of heat, and it also gets in the low 30's. I used radiant barrier roof pannels with air gap and R38 in the ceiling and R19 in the walls (3 coat stucco system) with metal roofing. It is conditioned space with (2) 2 ton mini splits but even without the minisplits it never gets unacceptably hot or cold. Running the minis it holds the temperatures extremely well. It was well worth the extra cost in my mind and would do it again.

 

[FL Guy]

Central FL here.
I just installed a radiant barrier and 2” foam board throughout my building. Along with an exhaust fan it’s very very comfortable in there. I can maintain 85°