Rigid Foam Insulation?

[superj]

guys, no issue. guys and girls, issue

 

[09fx4guy]

I would be a little more concerned if you were insulating your house, but considering you are insulating a pole barn, I would not be as concerned about being 100% perfect. If there is a gap between the wall covering (whatever you are using) and the insulation, there should not be much of a problem. The key would be to seal as many gaps as possible between the outside and the rigid foam. That is where you will have the most heat loss.

Just curious, how are you heating the workshop, and how warm do you want to keep it?

 

[Roert42]

Now that I think about. Double pane glass makes a good insulator because of the air sealed inside does not conduct. same thing with a vacuum sealed thermos. The problem is when the air is able to move.

The cold air is able to flow through the gap vs having to transfer the temperature.

 

[rumblecloud]

Just curious, how are you heating the workshop, and how warm do you want to keep it?

It's a 40x20x10 area. I have 2 inch hard foam over the top joists. There is nothing on the outside walls other than the 3/4 inch OSB and vinyl siding. The inside wall that separates the workshop from the rest of the barn is standard 2x4 on 16-inch center. I'll use rolled insulation there.
I am currently using a barrel stove for heat with supplemental bullet heaters as needed. This past winter with no wall insulation I was able to keep it around 40 to 45. And that's fine to work in. I'd rather not use the bullet heaters for long perios while I'm in there because of the carbon monoxide issue.
So in answer to your question, I'd like to keep it or near the 50 degree mark. I'd use the bullet heaters to start until the stove gets going then shut the bullets down while I'm inside.

 

[stmitch]

If I understand window R values, air has an R value. Iirc the gap between panes cannot exceed 5/8" or the air will circulate and transfer heat from one glass pane to the other. Less gap and the air is stationary and no heat transfer. Granted, I'm no scientist , but I've installed thousands of windows and looked into the insulation properties of them. So I'm assuming the same properties would apply to an air gap with other types of material, but I dont really know. But I do know that stopping air movement is critical to making the most of whatever type of insulation you have. Pressure difference between inside and outside will cause air movement thru the walls unless dealt with. I've pulled enough dirty fiberglass to see that first hand.

Yeah, I should've specified moving air. When air is completely contained, it's R value is 3.6. But it's not going to be completely contained in a typical wall structure like it can be in a window assembly. So you limit the air movement as much as possible, and pack as much insulation in as possible. The more insulation you have, the lower the chances of warm and cold meeting and causing condensation issues. An air gap allows for more air movement, and means you've got less insulation in the same area. Conversely, going with the thicker foam benefits you both in actual R value and in limiting air movement.

 

[09fx4guy]

rumblecloud- It sounds like you have a pretty decent setup and plan. It will probably heat up quite well in there. I look forward to your progress.