Non-faced insulation question

[shawn84&92]

I have a pole barn with double bubble insulation between the metal and the perlins. I have built 2x4 walls even with the posts and plan to insulate and sheet the walls with osb.

Today, I got a great deal on unfaced r-11 insulation 7ft wide and 100 ft long for $30 per roll. My question is since I have double bubble is it okay to use the unfaced insulation or do I need to put a vapor barrier between the osb and the unfaced insulation? If I need a vapor barrier, what do I need to use. I plan to sandwich the insulation between the osb and the 2x4's.
Thanks,
Shawn

 

[shawn84&92]

bump

 

[bullnerd]

I cant help you on this one .Over my head. I dont think you would want a moisture retarder on both sides of the insulation? I always thought it was supposed to "breath" to the outside. This will require a pros advice. Good luck.

 

[Highbeam]

You shouldn't have put in the bubble wrap. That is now the vapor barrier and it is on the wrong side assuming you live in a heating area and not way down south.

The problem is that warm moist air from inside the building will move on through the OSB and fiberglass until it hits that cold bubble wrap where it will condense like a cold can of coke. The trapped water will saturate your FG batts and rot your wood, grow mold like crazy.

First, remove the bubble ****. It's not doing you any good anyways. Then insulate, then cover with a poly VB on the inside and then put up the OSB.

 

[shawn84&92]

You shouldn't have put in the bubble wrap. That is now the vapor barrier and it is on the wrong side assuming you live in a heating area and not way down south.

The problem is that warm moist air from inside the building will move on through the OSB and fiberglass until it hits that cold bubble wrap where it will condense like a cold can of coke. The trapped water will saturate your FG batts and rot your wood, grow mold like crazy.

First, remove the bubble ****. It's not doing you any good anyways. Then insulate, then cover with a poly VB on the inside and then put up the OSB.

There will be about a 4 inch ir gap between the insulation and the double bubble, will that help the situation any?

 

[shawn84&92]

"The problem is that warm moist air from inside the building will move on through the OSB and fiberglass until it hits that cold bubble wrap where it will condense like a cold can of coke. The trapped water will saturate your FG batts and rot your wood, grow mold like crazy."

I don't understand, wouldn't it do the same thing when it hits the cold metal on the building?
Thanks,
Shawn

 

[Highbeam]

It won't hit the metal if you put the vapor barrier where it belongs which is on the warm side of the wall. The idea is to keep the warm, moist, room air from entering the wall cavity where it will eventually find a place cold enough to condense and then it is stuck there.

If you have a ventilated 4" air gap between the insulation and the metal skin then you are in better shape but still, not ideal. The foil wrap can only hurt you. Tyvek house wrap would have been a better idea.

 

[jannan]

You will be alright as long as you are very careful installing the poly vapor barrier. Be sure to tape all seams and tears. JMO

 

[shawn84&92]

You will be alright as long as you are very careful installing the poly vapor barrier. Be sure to tape all seams and tears. JMO

What I will end up with is:
OSB
plastic vapor barrier
unfaced insulation
3 to 4 inch air gap
double bubble
outside metal

Will this be okay?
Sorry to keep asking,but this is out of my knowledge range and I don't want to mess up.
Thanks,
Shawn

 

[CNGsaves]

What environment you in . . . hot, cold, or moderate?? What country?? State and city??

Now would be good time to Update GJ Profile with your Location.

 

[shawn84&92]

What environment you in . . . hot, cold, or moderate?? What country?? State and city??

Now would be good time to Update GJ Profile with your Location.

I am in Fort Smith, Arkansas.

 

[jannan]

What I will end up with is:
OSB
plastic vapor barrier
unfaced insulation
3 to 4 inch air gap
double bubble
outside metal

Will this be okay?
Sorry to keep asking,but this is out of my knowledge range and I don't want to mess up.
Thanks,
Shawn

Yes, as long as you are careful when installing the VB. Moisture that cannot travel thru the VB, cannot condense on the other side of the VB. Your reasoning, that you stated earlier, is correct.