The shop is a free standing 28x36 w/h cathedral ceiling , i should tear it down and put up a new 40x40 but i'll reno the thing for one last time and make it last a bit longer . Years ago it was ok when it was used for personal use being dry walled , now its where a fair amount of welding / repairs takes place plus i'd like to be able to wash equipment in doors thru the winter instead of out side . So yes , the walls are insulated and has plastic barrier under the dry wall " i checked" . I just did'nt know what was needed to keep the frost from happening to the sheeting , looks like am good to go then . Thank you guys for your help , it sure feels good knowing when your not making a mistake from guessing . Thanks again for all the good info ............ Ron .