[LisainOH]

We are building a pole barn which will be heated continually in the winter months, there will be no air conditioning and the building is well shaded in the summer. We are framing and sheet rocking the interior. Our finished walls will be 8' high. My question, should the wall insulation and vapor barrier extend only to the height of our finished wall and where the ceiling will meet or should it continue all the way up the side of the building into the unused attic space.

 

[Bud9051]

I assume you are in a cold area. If you also insulate and air seal the ceiling between the conditioned space and the unused attic area, then the vapor barrier would not extend up the walls of the attic. The VB needs to be on the inside just under the drywall and careful attention to all air sealing is a must.

If your interior wall framing is separate from the pole barn framing then you would want a layer of house wrap in there somewhere. Where TBD. What is your code required insulation level?

Bud

 

[LisainOH]

We are in central Ohio, zone 5. The building is for agricultural use and does not have to follow any codes or permits. The building will have R19 in the walls and R38 in the ceiling. Should the height of the wall insulation stop at the point of where the ceiling will be or is it ok to have it going up the wall in the unconditioned space

 

[Bud9051]

Will the upper unconditioned space be ventilated like a traditional attic? Since some moisture will find its way through the ceiling, that space will need to deal with it. Continuing the insulation up the walls in the unconditioned space should not be an issue, however, the air sealing and insulation (the thermal envelope) needs to remain continuous at the ceiling. If the walls of the pole barn are providing a path from floor to attic, that path needs to be blocked both for fire and air flow.

Without the detains of the construction it is hard to advise. Is the pole barn frame being used as the interior wall? Are there future plans for finishing the upstairs?

Bud

 

[LisainOH]

The upper unconditioned area has 2 18x24" gable vents, and a versa vent running the length of the roof. We are also considering adding an attic fan. The pole barn frame is being used with the interior walls, the framing is running between the posts. The ceiling will be a suspended grid ceiling, with vapor barrier and then insulation about a foot above the grid. The unconditioned space will not be finished in the future

 

[Bud9051]

A couple of problems here.
1. With just gable and ridge venting you have minimal height difference between high and low vents, thus minimal natural air flow. Normally a ridge vent will be installed along with soffit or low roof venting.
2. Use of an attic fan will depressurize the attic space and increase leakage of warm moist air from below.
3. A suspended ceiling does little to slow air leakage. Using a vapor barrier below the insulation is not the desired location. A vapor barrier needs to be in full contact with a rigid surface. As doors are opened and closed people are used to seeing curtains billow in and out in front of open windows. The same thing happens with a vapor barrier hanging below the insulation. As the wind huffs and puffs that sheet of plastic will pump air in and out of both spaces.

Being an agricultural application I have no background to say what is desired or required so that puts the ball back into your court. All I can do is state what approaches we use in residential construction and let you choose. Choose well.

If the inhabitants of this lower space will be generating lots of moisture then the exhaust fan might be better located in the lower portion, along with provisions for incoming air. What is your heating source?

Bud

 

[LisainOH]

Thanks for taking so much time to explain everything, we will be using separated combustion propane shop heating

 

[Bud9051]

I'm not sure what you mean by "separated combustion propane shop heating". Does it have a chimney venting to the outside or is it unvented?

Bud

 

[LisainOH]

A separated combustion unit is one that draws fresh air in from the outside and doesn't create a negative pressure in the heated space, yes it is vented.