Metal Pole Barn Ceiling Insulation, After It's Built

[flingwing1969]

I purchased the property next to mine for a few reasons, not least of which was the 36' x 48' metal pole barn, with 12' x 48' carport along one side, on the place. Besides the obvious, I didn't want some pot growers moving in and setting up a grow operation within sight of my main home.

At any rate, it is a nicely built pole barn with good room for three full height bays deep enough to put my firetruck in and still have room for a large mezzanine across the back of the shop. The roof is full span wood trusses, the posts are treated 4x6s, and no part of the building was insulated when it was built. I live at 4000' in the extreme southern Cascades and it gets chilly up here during the winter and we get a fair amount of snow and a total of around 70" of precip every year. As a result, I get times when it rains in the shop - condensation on the inside of the metal roof panels simply rains down on my stuff with the expected results.

I know most of the option available to me - leave it be and tarp my stuff, closed cell foam, open cell foam, blankets between the trusses, etc. I like Roxol for bats and certainly might consider using it, it's a tad expensive but easy to work with and self supporting. What I'm looking for is anyone with experience doing an insulation retrofit in a metal sided/roofed wooden pole barn and what you think. Thanks in advance.

 

[davedj1]

Is it cathedral or flat ceiling? If you are going to insulate on the flat then the Roxul would be OK. I'm not understanding the self supporting part unless you are talking in the walls. Most likely you will need to use something to support in in the ceiling. You may need gable vents, ridge vent and soffet vents. If you are talking about insulating the cathedral it's more involved for proper ventilation.

 

[mcfarmall]

Use white pole barn metal and screw it to the bottom chord of the trusses to provide an attractive finished ceiling then blow a foot of insulation in the attic with vent chutes stapled to the underside of the sheathing between the trusses at the eave. I did this in my pole building shop and in my attached garage...looks beautiful and a lot less work and weight than sheetrock. I assume the trusses are on 24" centers.

 

[coldsteelva]

Rather than try to insulate the roof proper, could you make it a cold roof from inside? Install a metal 'false' roof inside to capture and redirect any condensation and then insulate that false roof/ceiling. I'm not sure if I'm explaining that right, but hopefully others will chime in.

 

[KennyG]

mcfarmall has the right idea - metal ceiling with blown in insulation. That's what I did. Put a vapor barrier on bottom of the trusses before you attach the metal. Form in access holes to get into the ceiling. Because of the condensation issues, you might even consider vent fans in the attic space on the ends of the building.

 

[747driver]

First thing I would do is get some free flow ventilation going. You need to somehow get the eaves and roof ridge ventilated to create a airflow. Maybe install a exhaust/ventilation fan on the top gable ends. As already said ...what are the trusses centered on ( 2',4',8' ) as that will tell you what you can hang from the bottom chord.

 

[Brake Weight]

My uncle used roll insulation and then held it in place with chicken wire. Not very attractive but gets the job done and can be put up with just two people and an extension ladder. Measure your run, roll out the chicken wire and cut a little long, roll the insulation on top of the wire and attach in a few spots, tack up the low side then work your way to the high side.

 

[flingwing1969]

Is it cathedral or flat ceiling? If you are going to insulate on the flat then the Roxul would be OK. I'm not understanding the self supporting part unless you are talking in the walls. Most likely you will need to use something to support in in the ceiling. You may need gable vents, ridge vent and soffet vents. If you are talking about insulating the cathedral it's more involved for proper ventilation.

Thanks for the reply, I was beginning to think I was going to have to think this out for myself and thinking is hard.

I'm talking self supporting on a temporarily basis in the ceiling if slightly larger than the cavity, not floppy like fiberglass. I will likely use bird netting or the like until I get around to sheathing across the purlins. It is an open truss ceiling and I want to put the insulation between the 2' oc purlins to preserve the volume above the trusses' bottom cords; the purlins are mounted between the adjacent trusses' top cords so I have a nice 8" pocket.

No mater what I put up it is not going to be cheep but if the cost of installed urethane foam is more effective and only 10% or 15% more than Roxul, I would certainly think about going that route.

 

[flingwing1969]

Use white pole barn metal and screw it to the bottom chord of the trusses to provide an attractive finished ceiling then blow a foot of insulation in the attic with vent chutes stapled to the underside of the sheathing between the trusses at the eave. I did this in my pole building shop and in my attached garage...looks beautiful and a lot less work and weight than sheetrock. I assume the trusses are on 24" centers.

Thank you for that. It was a real consideration for me to do that but I really want to preserve the space between the trusses as my mezzanine floor will only be about 7' below the trusses bottom chords. I could do this on the part of the shop that is not above the mezzanine and may do that - cuts down on the heated volume as well. I'll have to keep that under consideration for sure.

Sheetrock has never been a possibility in the shop, I agree with you strongly there. It is for making things pretty but otherwise it serves little purpose (except maybe a bit of fire mitigation in doubled sheets). Even simple corrugated galvanized would make a nice ceiling and would reflect a lot of light - a thought if it is less expensive than the 5-rib.

 

[flingwing1969]

mcfarmall has the right idea - metal ceiling with blown in insulation. That's what I did. Put a vapor barrier on bottom of the trusses before you attach the metal. Form in access holes to get into the ceiling. Because of the condensation issues, you might even consider vent fans in the attic space on the ends of the building.

Thank you.