Insulating a ceiling and rafter vents

[camnick]

I am trying to get my pole barn all insulated. I have insulation below the metal roof to keep from sweating. I just got the walls spray foamed. Do I need to install rafter vents on the sides since I going to have cellulose blown in? Will I need a vapor barrier below the cellulose?

 

[rburke65]

No answers here. I think we would need more info.....that's probably why you haven't gotten any replies. Going to have cellulose blow in.......blown in where? Walls? Ceiling? Will you have a ceiling? This is not clear at all. Of course this is just my opinion.

 

[camnick]

Sorry so confusing. I found out some answers already. I am going to put a metal ceiling in. I am going to have cellulose blown in after, on top of the ceiling metal. I found out I don't need a vapor barrier above the metal. Talking to a couple of contractors, since I have an insulation blanket below the roof metal, I won't need the Vapor Barrier. I also found out I do need rafter vents to help the attic breathe.

 

[klogan121]

Sorry so confusing. I found out some answers already. I am going to put a metal ceiling in. I am going to have cellulose blown in after, on top of the ceiling metal. I found out I don't need a vapor barrier above the metal. Talking to a couple of contractors, since I have an insulation blanket below the roof metal, I won't need the Vapor Barrier. I also found out I do need rafter vents to help the attic breathe.

You mean an insulation blanket above the roof metal, not below right?

I'm putting in a metal ceiling in my pole barn too and was wondering if a vapor barrier is required too. I am insulating with R30 fiberglass batts.

 

[Highbeam]

He has both. Inulation below the roof metal and above the ceiling metal.

I would still put the vapor barrier above the ceiling metal beneath the insulation. The vapor barrier acts as an air seal to prevent your hot air from leaking up into the attic via the chimney effect. Metal roofing/siding does not make a good seal and you will have a leaky ceiling without putting something up.

What's a rafter vent? I have installed a continuous ridge vent as well as soffit ventilation into my pole barn in preparation for a ceiling. In any case, you would want attic ventilation and there are codes you can follow to be sure it is adequate.

 

[klogan121]

What's a rafter vent? I have installed a continuous ridge vent as well as soffit ventilation into my pole barn in preparation for a ceiling. In any case, you would want attic ventilation and there are codes you can follow to be sure it is adequate.[/QUOTE]

http://products.construction.com/swts_content_files/20855/E715704.jpg

The above link shows a picture of a rafter vent, which directs air from soffit up through the ridge or can vents in attics.

 

[camnick]

That's basically the same type of rafter vent I installed. I don't have a overhang, so no soffit vent. the only air that circulates is from the corrugation on the metal on the sides and the ridge vents.
I just tried getting a couple of quotes to get the metal installed on the ceiling. I just got one back. HOLY ****!!! The metal cost approx. $2650 for 5200 square feet and that's me picking it up from the manufacturer. I thought that wasn't too bad since it includes the F channel and the screws. The labor quoted was $5000. It cost me a little more than that to have the whole pole barn shell built! I maybe putting up the metal myself.

 

[klogan121]

I am helping on a crew put up metal on a 100 x 50 shop, and its going up pretty fast with 12' long pieces and two guys installing it on a scissor lift.

After seeing this tin go up, I concluded that I'm installing this myself on my ceiling too! Looks great and no painting it either! Can only buy a few pieces at a time though!

 

[camnick]

I found out I can rent a scissor lift for $330 for a week. It may take a while but it will cost a lot less.