Pole barn Insulation Planning ?'s

[HunterDan]

I know this has been beaten over and over, but I've searched and couldn't really find any help.

My building is delivered, and am starting this weekend. 40x48x16, 8' post spacing, 4' truss.

I will be using the space as a garage/shop, and will eventually be heating it. Im in northern MD. So we have 100+ in the summer, and can get down to 0 in winter.

I'm doing the double bubble on the roof and walls. I'm at the point now, where I'm trying to decide. I know spray foam is ideal, but for a building this size, that's just out of my price range. I'd like to keep it all one open shop area.

I like the 4x8 foam board for ease. My thoughts now, would be to do 1.5" cut to fit between the perlins, then either fiberglass over top, or a bigger foam board.


So my questions:

• Would I gain much by cutting the 1.5" and going in between the purlins? Or would I be better off just doing 3" and going overtop the purlins (leaving that air gap between the double bubble and the back of the foam Board)

• For the roof, should I do the foam board in between (or over top) the girts, or hang my ceiling and just blow in insulation on top? Or both?


I'm sure ill have more questions but thank you for the input!

 

[mopar440_6]

I'm in the process of building a similar sized building in south central PA so I've got similar weather.

I think you may actually lose R-value by going in between the purlins because now the purlins will be a thermal gap. What I would like to know is why foam board? I would think it would be much more cost effective to get batts of fiberglass thick enough to fill the entire wall cavity and put those up. If you're looking to seal the building up better from an infiltration standpoint you may want start looking into spray foam rather than foam board.

As far as the attic, we're just going to put the ceiling up and run it up to R-40 worth of blow in insulation. Its the best option for me and my builder from both a time and cost standpoint.

Just for reference, according to the load calculations for my building, the biggest losses are infiltration and the walls (R-21 fiberglass batts).

 

[bullnerd]

Check out my build in my sig.

I copied what Morton buildings does.

Skip the double bubble.

Find blanket fiberglass, blow in the ceiling as much as you can afford.

Im not an HVAC guy, just my opinion based on a lot of research and spending years in my neighbors Morton building.

 

[HunterDan]

Bull, I've tried searching and could not find any 8' fiberglass rolls, where did you get yours?

I've heard both sides of the double bubble. The main reason I'm doing it is because I pushed for a little bit bigger building than I originally planned, so I may not be able to insulate it for a while. I figured the double bubble will stop any condensation problems in the mean time

 

[bullnerd]

Bull, I've tried searching and could not find any 8' fiberglass rolls, where did you get yours?

I've heard both sides of the double bubble. The main reason I'm doing it is because I pushed for a little bit bigger building than I originally planned, so I may not be able to insulate it for a while. I figured the double bubble will stop any condensation problems in the mean time

I got lucky and bought direct from a Morton contractor. There is one in N Jersey so I picked it up. He said they buy it by the rail car load, thats why such a good price. That might be worth a try still. Ive heard guys on here that are farther west say they can find it. I think the maker and part number is in my thread.

I would talk to an expert on here before the double bubble. The problem is when you go to insulate, you will have to remove it? I think.

 

[HunterDan]

Now that I have not read, I'll have to look Into it more.

Can anyone shed any light on this?