The reason I had my large steel sided pole building (my toy barn) built with a wood roof and tarpapered and with high quality shingles and has a full length ridge vent down the middle was because of sweating issues which can or often occur with a steel roof. 22' high to the roof peak, has a 6" thick concrete floor angled from all 3 walls toward the wide door, 12' 6" clear span inside all the way thru under the ceiling lights which are movable should I need another 6" vertically, 14' wide by 13' high double sliding door and 2 entrance doors, not insulated inside like I'd originally planned to do but I do have heat on if I'm inside working for any length of time in cold weather. Perfect scenario for lots of condensation by frequent heating and cooling here in Michigan. Hot, cold, hot, cold, hot, cold...
Never sweats a bit nor does any thing inside rust either as I have lots of tools and works areas inside including welders, press brake, 2 hoists, gobs of bench tools, motors, fabrics/wood/steel materials/and even lots of foam cushions, lawn and yard etc equipment, drill press/saws/sanders, etc, boats, outboards, bikes, RV's etc. You name it! Yes, heat does escape in winter when heating but so does any moisture go out with it which is then replaced with outside colder dry air. Bye bye water vapor and humidity and welcome in to the dry air! Venting is ultra important!
BTW, my building was built in 1987 about Thanksgiving time which is roughly 29 years ago now and nothing, on, or in the building, has ever rusted and the original roof never leaked and is all original including the 2 X 6 trusses, the shingles, and all still in fine shape. Probably going to out live me and I plan to live to 150 young!
A superb CC LB 4X4, GM HD Diesel, airbags, Rancho's, lots more
Lance Legend TC 11' 4", loaded including 3400 PP generator and my deluxe 2' X 7' rear porch
29 ft Carriage Carri-lite 5'er - a specially built gem
A like new '07 Sunline Solaris 26' TT