Barn roof insulation

texas42 · Jan 21, 2018

After having owned several metal roofed buildings, from uninsulated to batts, to styrofoam to now spray foam, I can attest the best insulation on a metal roof in sprayed closed cell foam. The closed cell foam sticks really well, does not fall down, eliminates condensation and quiets the roof noise in a rain storm.
A good cell foam installed would make it look good.

Deere Dude · Jan 21, 2018

What about tack spray where you would spray the metal that is showing, wait a few seconds and put the same insulation back in place. It wouldn't be invisible but maybe some white tape on the seam after it is glued in place.

goeduck · Jan 21, 2018

texas42 said:
After having owned several metal roofed buildings, from uninsulated to batts, to styrofoam to now spray foam, I can attest the best insulation on a metal roof in sprayed closed cell foam. The closed cell foam sticks really well, does not fall down, eliminates condensation and quiets the roof noise in a rain storm.
A good cell foam installed would make it look good.

How do you deal with the purlins?

texas42 · Jan 21, 2018

My "rafters" are "C" channels - just encased them with foam also

Barnbuilder · Jan 22, 2018

I would be concerned with lumber absorbing moisturewith spray foam.

The bubble wrap that is up there is just deteriorating. If I touch it it pieces will just fall. And it will be a continual process.

EddieWalker · Jan 22, 2018

Closed cell foam will keep out moisture. That's why it's used for floating boat docks. Open cell foam absorbs it. Open cell is cheaper and easier to install. It has a lower R rating then the same thickness of closed cell.

Barnbuilder · Jan 22, 2018

Yes but if the moisture runs down to the purlin it will get absorbed will it not?

texas42 · Jan 22, 2018

My observation is that with the closed cell foam insulation, moisture does not collect on underside of metal roof, therefore no moisture to run down to the wood purlin. If really concerned about this leave the bottom of the purlin bare so it could "breathe"
You might try contacting a local closed foam installer and see if he has jobs he had done like yours and go look at them.

Barnbuilder · Mar 17, 2018

Well we're going forward with this project. I tried to sway them to take the roof off. Put new insulation down then put the old metal back down with new screws. Even gave them an a cost to replace the metal. They went with the option to put a metal ceiling up with foam board insulation between the rafters. Looks like we will put some T&G YP under the collar ties to give a little contrast to the metal.