Condensation on metal roof

[Southern Gardener]

Not too long ago I converted my chicken coop to my potting shed / tool shed. It has a metal roof and is "open" or "vented" around the eaves and is not insulated and I have no plans to do so. The problem is the condensation that drips off the roof inside the shed. Is there anything I can spray or paint on the inside of the roof to keep the roof dry?

 

[Collector]

Maybe you need more ventilation, only thing I can think of. I used the 1/2" foam board under our metal shed roof and have no moisture problems. We may be in a dryer climate than you also.

 

[Ridgerunner]

There was a recent thread somewhat about this on the chicken forum. If the air inside is humid and the roof is cooler than the air, you are going to get condensation on the inside, or even frost, not matter how well it is ventilated. I get exactly the same thing you are talking about in my coop and under a very open shed roof. If you are getting condensation or frost on the inside and not on the outside, then it probably is a ventilation issue if you have a moisture source inside, like chickens breathing and pooping. I would not expect a moisture source inside that shed, so I'd think it is just humidity from the air.

The only things I can think of are to insulate the roof (which you said no to already), box it up tight where outside air can't bring moisture in (yes, less ventilation), or find a way to live with it.

 

[thistlebloom]

My tool shed is sided and roofed with metal and has open eaves all around. It always drips from condensation, and the air around here is generally dry. I think that just comes with metal roofing and the only remedy that I've seen used is insulation.
I'm interested to see if anybody comes up with a different solution though.

 

[lesa]

Being in the metal storage business, this is a problem. The industry calls it "condensation barrier". On my old buildings that consisted of 4 inch insulation with the outside a layer of plastic. In the newer buildings it is a very thin layer of foamy insulation (similar to the padding you put under wood floors.) I have also used tyvek for that purpose. You just need something to catch the drips. It isn't a whole lot of water, just dripping moisture. The roof heats up fast and everything dries right up.... I think the rigid foam would work fine too. Good luck!

 

[Southern Gardener]

Being in the metal storage business, this is a problem. The industry calls it "condensation barrier". On my old buildings that consisted of 4 inch insulation with the outside a layer of plastic. In the newer buildings it is a very thin layer of foamy insulation (similar to the padding you put under wood floors.) I have also used tyvek for that purpose. You just need something to catch the drips. It isn't a whole lot of water, just dripping moisture. The roof heats up fast and everything dries right up.... I think the rigid foam would work fine too. Good luck!

It is very humid here - pretty much all the time. Lesa, how does this rigid foam attach to the metal roof?

 

[lesa]

The problem with attaching anything to a metal roof is you don't want to put anything through it.... Take a look at the structure and see what you can figure out. We have metal 2x4's that we can attach to. You might be able to use wire, etc. You'll have to be creative, and I am not promising it will be an elegant solution! Whatever you use for material doesn't need to go right up against the roof- just catch the moisture. Keep us posted!

 

[Southern Gardener]

The problem with attaching anything to a metal roof is you don't want to put anything through it.... Take a look at the structure and see what you can figure out. We have metal 2x4's that we can attach to. You might be able to use wire, etc. You'll have to be creative, and I am not promising it will be an elegant solution! Whatever you use for material doesn't need to go right up against the roof- just catch the moisture. Keep us posted!

Oh! That makes sense. I have wood 2x4's holding up my roof so, yes I can rig up something to catch the moisture.

 

[lesa]

Oh how I wish I had something wood in my buildings to attach to! You should have no problem, with wood beams!