Metal building condensation (help please)!

[Bama67]

I'd call the builder and tell them of the problems, and ask for a solution. If they request new money, cross that bridge when you come to it.

I contacted the maker of the steel building, we'll see what they say.

I am kinda pissed at the builder that put it up for me, he is a big time construction guy around here, and builds lots of steel buildings.
It seems as if he would have known that it would do this, or at least while while he was building it and said (Hey Bama, you might want to do some type of venting while we are putting it all together.)

 

[hizoot]

To help minimize the problem...keep the doors shut . I know when I opened my doors when it was cooler inside the shop than outside...my tools would immediately condensate when the warmer air hit'em .

 

[Bama67]

To help minimize the problem...keep the doors shut . I know when I opened my doors when it was cooler inside the shop than outside...my tools would immediately condensate when the warmer air hit'em .

Thanks, but the problem I am having is with the doors shut tight.

 

[dstig1]

Real insulation will help a lot. Foil faced bubble wrap is unfortunately the snake oil of the insulation biz. It is barely R0.5, and certainly not R10.

The goal is to keep the condensing surface above the dewpoint of the air. You are obviously in a hot-humid climate so I suspect everything is inside out from up here, but the principle remains the same. If you can keep the interior of the metal warm enough (higher than the interior dewpoint), the humidity in the air will not condense on it. You need to do two things to accomplish this: keep the surface warm and keep the interior air away from the surface (air leaking past insulation will carry the humidity with it and then condense on the colder metal). Closed cell spray foam is a great way to do that, though it is pricey.

Sources of moisture include the air and also the ground. Sealing the ground will stop moisture from coming up through it and remove one major source, but that isn't really an option if you don't pour a slab inside. If you do, then you need to put plastic underneath and seal it (even better would be some insulation board, sealed).

 

[Bama67]

Real insulation will help a lot. Foil faced bubble wrap is unfortunately the snake oil of the insulation biz. It is barely R0.5, and certainly not R10.

The goal is to keep the condensing surface above the dewpoint of the air. You are obviously in a hot-humid climate so I suspect everything is inside out from up here, but the principle remains the same. If you can keep the interior of the metal warm enough (higher than the interior dewpoint), the humidity in the air will not condense on it. You need to do two things to accomplish this: keep the surface warm and keep the interior air away from the surface (air leaking past insulation will carry the humidity with it and then condense on the colder metal). Closed cell spray foam is a great way to do that, though it is pricey.

Sources of moisture include the air and also the ground. Sealing the ground will stop moisture from coming up through it and remove one major source, but that isn't really an option if you don't pour a slab inside. If you do, then you need to put plastic underneath and seal it (even better would be some insulation board, sealed).

I do have a full slab, with sheeting underneath it.

Reckon what it would take to heat this huge building up to prevent the issue. I could probably source some used poultry house propane heaters, but I have heard that those contribute more moisture to the air, and those units are far from efficient.

I am thinking two cupolas, maybe 30"x30" with exhaust fans in them would pull out alot of air, and outside air could come in thru all the gaps above the roll up doors.
It seems to me that this would move alot of air thru the building. But as you can tell, this definately isn't my area of expertise.

 

[dstig1]

Go to Building Science Corporation and look around a bit. You may find a case study that is similar enough to yours to help.

My guess is that short of sealed insulation, you will probably need to go with serious fans, like you are suggesting.

 

[AGGIE00]

Okay, say I did tear down all the new insulation in my building. How much would it cost me to spray an entire 40x60 building with 16ft eaves, roughly?

$1.00/SF, so about $5600 minus whatever doors you have. It obviously isn't cheap, but will serve you well. Closed cell foam is structural and will significantly stiffen up the walls and make it very hard to remove screws and break into. It also ensures there is never any moisture between it and your sheetmetal. Closed cell foam will also seal any and every leak that may exist. The one major downside is that if you ever damage a panel it is not easy to replace and when you do it will need to be resprayed. PM me if you have any questions.

 

[AGGIE00]

BTW, my building is 50x75x16 and is not vented. We have no problems with moisture. I'm not trying to get business from you as there is no way I could travel that far, I just know how good the product is.

 

[Bama67]

I know the foam is some good stuff. There is just no way I can afford to do that right now. If the venting doesn't do it, then I guess eventually I have no choice.

 

[beppington]

Is this a metal bldg characteristic more so than wood? I have a wood barn (plywood walls) with a metal roof, & I think the metal roof does get wet sometimes, but not so much that everything else is wet, too. I wonder if maybe the wood is just enough better of an insulator than metal walls?

I would be very disappointed if my bldg was doing what yours is :thumbdown: