I just finished some numbers on insulating the "cold 60ft" end of our shop.

Frankly, I was quite surprised...........first, at the total cost after adding in all of the little things, like Cokes every two hours, etc............and secondly, the cost of foam vs blown in.

Foam was a lot closer to the cost of blown in-----------except that the RValue of foam for the dollars consumed are a lot less than the RValue for the dollars for blown in fiberglass.

However..........some of you indicated before, and it "feels" rightfully so, that the foam closes so many holes that it produces more retained heat than would be expected, so the "RValue" might not tell all of the story in this type of drafty environment.

I stood in the middle of that pole bldg this afternoon---------I guess there is a difference in looking at something over and over, and then finally actually seeing it----------and there are so many damned air leaks that I am surprised the snow doesnt blow in.

Ok------the question.............

The only thing that really bothers me is the unknown about what the heating conditions will be if we...........foam the roof itself.........as compared to dropping the ceiling.

If we drop the ceiling, we do not heat anything above 16ft.........and therefore the area above can get cold all it wants.  We have decreased the number of cubic feet heated.

If we spray the roof.........then we are still heating the area above the ceiling joists (16ft.).  That additional area is about (60ft wide x 8ft tall x .5 x 60ft long) = 14,400 cubic ft.

If we put in a, say, 36 or 48 inch cage fan (like we use in the current shop) to bring the heat down from the "attic" area........and given the insulating barrier characteristics of the foam.................would the heat at ground level still be reasonably the same as it would be if we were heating only the 16ft???

I suspect that heating that space above the joists would probably not amount to a Tinkers Dam as to effect at ground level............any opinions??

 Do you who have sprayed the roof, and not dropped the ceiling..........wish you would have done otherwise?

It appears that it would cost about 4,000+ to correct the hicky later.

Thanks.