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TOPIC: Condensation Issues

Condensation Metal Roof

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4 Years ago I had a 40x50 feet red iron building with 20 feet side walls built. It is on a concrete slab. 1/12 foof pitch. The back 20 feet of the shop I built a two story apartment and that is what my family is currently living in. When I had it built I put fabric over the metal rafters and blew in fiberglass insullation to fill the gap. I do not have a drop ceiling in the apartment upstairs so the fabric is what you see. I noticed it was sagging really bad by the eaves of the apartment. I checked it out and the fabric is full of water. I punch a hole it it and probably around 10 gallons of water from each side. Would this much water be caused from condisation because it can't breathe above the apartment area or is that even possible. I have a wood stove burning in the garage and keep it really hot in there. I would say up at the top of the roof line could reach 120 degress would be a fair guess. The shop does have gutters and I let them get full last fall so thought maybe it was from that but nothing ever got in the shop part of the building. Any help would be great. Thanks
Guest User

1/21/2010
Great article on condensation in Ice arenas. The water in the insulation is from the relative humidity in the air and it is condensing as it reaches dew point against the cold underside of the roof. You will need to either vapor barrier the underside of the roof, reduce indoor humidity (not really possible to get it low enough), or ventilate through insulation. The pdf is as it pertains to summer ventilation, however, the situation is reversed in your application if you are talking about winter time frames. Google search "Summer Condensation in Ice Arenas" Eric Novotny
Eric Novotny
An informed customer is the Best Customer!

1/25/2010