stick building - metal or shingles?

What you're doing unfortunately sounds to me like you could have some major condensation issues. What is the reason for not insulating this area? I assume it has something to do with not wanting to hold heat in during the summer but keep in mind that insulation also keeps heat out during the summer.

We will be putting up a stick framed (wood trusses) building to be used as a pet crematory. We have been told to not insulation the building area where the cremators will be housed. The building will be 24' x 40' and will have and office and meeting room taking up about 12' x 24' of one end. The office area will be 2" x 6" walls with sprayed insulation and the ceiling will have at least and R-38 insulation. It will be very hot, easily over 120 degrees in the building during cremation. We plan on using 7/16" OSB, house wrap and vertical metal siding on the walls. There will be 2 overhead garage doors, a 9' x 8' on the east (front) of the crematory and a 8' x 8' door on the west side. We will also have make-up air and exhaust fans per the manufacturers requirements with about 20 air changes per hour. We also will put in soffit vents and a continuous ridge vent system. My question is: with no insulation in the walls or ceiling, could we put down 5/8" sheathing, ice & water shield, and standing seam metal roofing, or would we be better off with shingles.

The heat inside the crematory area will be pretty high whenever the cremator is running. The exhaust fans will be set to kick in at about 85 to 90 degrees. The overhead doors will be open while operating, even in sub zero weather. None of the crematory operators that we talked to had ceilings in their buildings, they said the heat would be to much, even in the winter with the doors open. Maybe we could possibly spray insulation between the trusses against the bottom of the sheathing (I'm not sure how that would work?). I'm also concerned about the walls, they recommend not insulating them either.