My pole barn roof sweats like nobody’s business.
Nothing between the rafters, just metal roof on wood.
What are my options?
TIA!!
Tyvek or the like? When does it sweat/drip? Mine will if it is really foggy out, but just a tiny bit. My ceiling is bare metal with that plasticky material over it.
Maybe someone else can better answer your question, but AIR FLOW is going to be your friend to deal with condensation.
What sort of circulation system do you have in place?
After the fact, you have a few options. Insulating during construction would have been best. I would look at cutting and placing rigid pink foam between the trusses or having foam sprayed.
You can dry up condensation (or avoid it), like beau159 suggests, with air flow. I am interested in this. Do you use fans or vents? Is this comfortable in very cold weather?
You can also insulate to avoid condensation in the first place. The idea there is to insulate the ceiling so that the warm air doesn’t touch the cold surface of your metal roof. That can be done with a cold roof system or a warm roof system. (You may use different terminology but that’s what I learned). Both systems have their advantages and disadvantages.
The warm roof system would be something like spray-on foam insulation applied directly to the underneath surface of the roof. No additional vapor barrier or air space is needed.
The cold roof system would use fiberglass or blown in stuff. A cold roof uses a vapor barrier, then the insulation, then an air space with plentiful vents. The vents are important because any little bit of warm air which makes its way past the insulation will then pass out through the vents, rather than create a pocket of warmth next to the cold metal roof. I had a retrofit done on my house once and the guys blocked the vent holes when they installed the extra insulation. The weather was super cold and a lot of ice must have formed up there because the weather warmed up, the ice melted, and water poured through my ceiling. What a mess!
If I were you, I would make a pros and cons list of the various systems.
Material cost
Installation/labor cost
Time to install
Durability/Replacement life
Maintenance needs/problems
I have heard a few things about maintenance issues. Some people report problems with mice and birds and bugs getting into the fiberglass. That might be an issue of poor installation. The foam insulation is a bear to remove if you have to access a conduit or pipe or anything under the foam.
I wouldn’t bother insulating, because it’s expensive, and a great big bed for rodents, unless you do a fantabulous job at sealing it.
I’ve seen cupolas successfully added to barn roofs, with vents (similar to shutter vents). They look nice, and act as chimneys to exhaust air and humidity up and out of the barn, whether in freezing cold winters, or baking hot summers. Makes for a much more comfortable environment.
[QUOTE=Romany;7818690]
I wouldn’t bother insulating, because it’s expensive, and a great big bed for rodents, unless you do a fantabulous job at sealing it.[/QUOTE]
I concur on the rodents in the insulation…and the subsequent black snakes chasing said rodents! We had some exciting times last fall when a large black snake took over mouse patrol in the barn insulation - he fell out a couple times almost on top of us.
What are insulation options for new construction? I’m planning on a 36x36 barn with 6/12 roof and loft sheeted only in the center (floor open over the stalls) 12 ft or so. Vented eaves and continuous roof vent. Will I need insulation to keep my roof from raining condensation?
[QUOTE=gypsymare;7820423]
Will I need insulation to keep my roof from raining condensation?[/QUOTE]
Yes. Typically, they roll insulation out between the trusses and steel.
But what type? My previous barn builder never told me what they priced out and this new one didn’t sound very informed on the options so I’d like to be able to say I want brand xxx.
No brand, it comes in long rolls that they put down as the roof goes on. It does not have a very high R value, just enough to prevent condensation.
[QUOTE=gypsymare;7820423]
What are insulation options for new construction? I’m planning on a 36x36 barn with 6/12 roof and loft sheeted only in the center (floor open over the stalls) 12 ft or so. Vented eaves and continuous roof vent. Will I need insulation to keep my roof from raining condensation?[/QUOTE]
IMO and experiance don’t use metal that is not installed over a decked roof. Even then the life span of the decking may be cut considerbly because of the mositure build up between the wood deck and the matal roofing. Even then I am not sure if it will completly eliminate the problem. I don’t think it is recomended to intall metal roofing panels over decking.
Metal is generally chosen because it is cost effective. It does not require the additiional expense of materials and labor that shingles do. It is secured using perlings which leaves the underside exposed. So any building that is located in a high humity area is going to “sweat” under certian conditions. Compounded by water vapor with horses breathing. A barn load of horses is going to produce a lot of warm water vapor. In the winter the underside of a metal roof can and will ice up. As the day warms up and or solar gain will melt the frost and it will drip. And or melt and run down the sheeting to a cooler/freezing area of the roof and form icecycles.
I would think a properly sized cupola may fix and or cut down on the problem. Plus the added benifit of eliminating the “stuffyness” of a hot barn in the summer. Warm rises, cool air sinks.
IMO, but not experiance because I do not like metal roofing for various reasons, to fix the problem in an existing barn is to have spray foam insulation installed. It should be far more cost effective then installion anything else which would be very labor intensive. And problematic as others have pointed out. Foaming is priced by thickness and I don’t think it would have to be very thick to take care of the problem. An HVAC engineer should be able to give the exact thickness needed.
If you deck and shingle there shouldn’t be a problem. My 22 stall barn doesn’t sweat . Nor has any barn I have worked in that is decked and shingled. All have been in high humidity locations. Adding a cupola not only looks good but has its benefits also.
[QUOTE=Vindicated;7817628]
My pole barn roof sweats like nobody’s business.
Nothing between the rafters, just metal roof on wood.
What are my options?
TIA!![/QUOTE]
Are the metal roof panels installed on a wood deck or are the undersides exposed?
paint the roof black as the metal is cooling allowing the vapor to condense
You might want to give more details about the size of your barn, how many horses are stalled inside, whether you store hay in the loft, and what part of the country you live in for an idea of weather extremes and humidity. That way, people from different parts of the country can give you opinions based on similar conditions.
