Help me insulate my pole barn

[NonTypicalCPA]

After 10 years the gas company has finally run natural gas on my private drive, so I'm going to add a furnace and heat my pole barn - 30x40x12. Problem is it isn't insulated, except I planned ahead when I built and put in insulated doors. I want to tackle this project myself. If I start with the ceiling how should I proceed? Currently it's open rafters. Can I just add a rigid foam board type on top of the rafters? Or should I add a sheeting to the bottom side of the rafters and blow in or roll in insulation on top of the sheeting?

 

[GManBart]

What size is the truss spacing?

The problem with the rigid insulation is that it gets pretty expensive. Since you lose the most heat through the ceiling/roof, you want the highest R-value possible in the ceiling, and that means going with the 2" thick stuff (R10) which will cost you something north of $1250 (going off normal Lowes/Home Depot pricing).

Mine has 4' truss spacing, and my neighbor gave me a big pile of 4' wide insulation rolls from a demolition project he did a while back (sound studio). I secured them with twine and some 1"x1" wood slats. I'm going to cover it with steel panels, and then blow insulation over the top. The steel panels will run me about $650 at Menards (best price I've found so far).

This is what it looks like now that it's hung, and the partition is up and insulated....it'll be a while before I get to sheeting it in steel. I'll probably add a vapor barrier as well (I already have the material left over).

 

[franklin2]

You probably will need some sort of hard sheeting. The roof above should be ventilated somehow, and all it takes is a gust of wind when you open one of the big doors to "blow out" the foam sheeting. It will probably move and squeak each time someone opens and closes a small personnel door also.

 

[Mendonsy]

Regardless of what you do about insulation you might want to look into overhead radiant heaters. They do a better job of heating areas with high ceilings than trying to heat the air.
Space Ray

 

[pmsmechanic]

I haven't checked this out myself but was told that a do it yourself kit for sprayed on foam insulation was very little more money than fiberglass bat insulation. I googled it and there are lots of kits but I didn't go to the next step of comparing prices. If I ever insulate my storage this is probably the way I would go.

 

[Cat_Driver]

I second the spray foam. It will fillr all voids that any other insulation can not get to.

 

[KennyG]

The problem with spray foam is you have to have something to spray it on. If you insulate the underside of the roofing, you have just that much more overhead space for all the heat to go into. I think a ceiling (liner panel) over a vapor barrier with lots of cellulose blown in on top of it is the most cost effective way to go.

Spray foam makes more sense in the walls to me. Of course there are lots of other options there also.

 

[franklin2]

I want to do my garage also. Besides the insulation keeping the temp more stable, I can paint the hard ceiling white and that gives a lot more light to work by underneath.

 

[NonTypicalCPA]

I definitely need to add the ceiling then insulate, I have gable vents in the peaks. I was thinking spray insulation in the walls, but I would probably hire that out and I'd like to make this a do-it-myself project. My father in law spray foamed his shed and loves it, but his pockets are deeper than mine. I'm going to get a quote just to find out the cost.

Thanks for the link Mendonsy, I was planning on looking into that type of heater, but wasn't to that point yet. Any idea how much they cost compared to a forced air unit?

 

[KennyG]

As I have advised a number of times, bite the bullet and use prefinished white metal liner panel for the ceiling. It weighs less so you don't add as much load to your trusses and it eliminates painting for the next 40 or 50 years. Plus it looks a lot better than any kind of plywood, OSB, drywall etc.