metal roof will it sweat ?

here the question building a pole barn style home w/t metal roof. installed gable vents down both side 50Ft each. also installed temp control side ex fan. we will have 12" of blow in insultion on ceiling (still framing) so i'm asking will the roof sweat?

 

My hangar is not insulated and the building and everything inside sweats during fall, winter & spring. It has only one roof vent so it does not have the proper ventilation like your barn roof.

It sounds like you will have good ventilation which should minimize sweating. If the metal roof stays close to the outside temperature or warmer you will not have sweating. Good ventilation will help keep the roof temp close to the outside air temp. Then once the sun hits it the roof will warm and dry what little bit bit of condensation formed during the night.

 

Welcome to the forums lee!

I agree with Pilot Dane. Both my house and barn/shop have metal roofs. The underside of the barn roof sweats from time to time but I've never noticed the underside of my house roof being wet. My house has good insulation and ventilation, the barn has neither.

 

Metal is one of the more sought-after roofing materials for log homes. Usually made of steel, aluminum or copper, the most commonly discussed metal roof is the standing seam - sometimes called vertical panel - roof. You can also get metal shingles that resemble cedar shakes, slate, or tile. There are several advantages to using a metal roof, not the least of which is its fire resistance. These roofs are also remarkably lightweight, and stand up to hurricane-force winds. This roof will generally cost about $100-$600 per 100 square feet (very big range of materials and composition). Life expectancy is anywhere from 30-50 years up to 100 years.

 

It appears you plan to install your metal roof w/o having an underlayment. I could see that roof sweating although agree w/ the points made by Pilot Dane.

I have three buildings with metal roofs, and none sweat. These metal roofs have a plywood sheath and a peel & stick rubber membrane across the entire plywood deck that prevents moisture from coming into contact w/ plywood . . . the rubber membrane was mainly installed as an added layer of protection in the event a hurricane ripped a metal panel(s) from roof thereby preventing heavy rain from soaking the plywood or allowing water to enter through seams.