Pole barn condensation

[karman 4564]

Thanks everyone,
From what I learned from all of you was,I should make sure the contractor installs tyvec on the outside walls prior to the steel going on to act as a vapor barrier and install ceiling fans,
I like he idea of vents at each end of the building and will look into that.
Here's what I plan to do...install insulation covered by 1/2 " osb,on the walls.white steel on the ceiling with blown in insulation in the ceiling.
Will this alleviate any condensation,

I got inspiration and ideas from all the threads I've read about post barn builds and I plan to post pictures,

 

[RayfromTX]

Tyvek (spun polyolefin) is not a vapor barrier. It is designed as a drainage plane that allows vapor to pass freely through it. It has a perm rating depending on which version or manufacturer that varies between 7 and 60 perms. It resists liquid water if it is properly installed but it almost never is.

Fiberglass insulation allows water vapor to pass freely through it and also suffers from movement of air through it. It will allow convective loops to form within a wall that can carry large amounts of water vapor through it where it will collect on any cool surfaces that it finds. I have seen dramatic failures caused by this phenomenon but it will not be your problem. Your problem will be allowing water vapor to pass straight through your assembly and collect on the underside of the roof structure.

The second biggest problem you will encounter is related to the steel framing members. Steel passes heat easily through it and not only will you suffer thermal losses that create comfort and cooling and heating cost issues, you will also have moisture collect in certain climate conditions when the steel is cold in winter months.

Unfortunately, these issues are too complex to teach as an aside in a discussion forum related to other topics such as pole barns and tractors. There are discussion forums related to building science where these issues are discussed and understood. I'm sorry if my ability to convey the issues is inadequate. It is very important to me as I hate to see building failures and it happens all around me. People never find the money to do it right the first time but they seem to find the money to fix it later at a much higher cost.

Best of luck with your project.

 

[ultrarunner]

Sounds like it would be better to avoid metal buildings all together unless it is something like an open carport or lento?

 

[bkrgi]

RayfromtTX is hitting the nail hard on the head....take his advice 100%
For outright steel buildings I would spray foam them ...only viable option IMO.
If your doing a wood pole barn with steel sheeting exterior I would frame in insulate the walls and ceiling with fibreglass or better yet rock wool or even blown in cellulose and vapor barrier the whole inside before putting up the interior cladding/sheet rock or ?
Before adding the exterior steel cladding, strap to add a airspace to vent for the walls then tyvek then cladding...for roof use tar paper below the roof steel as no matter what the steel is going to condensate regardless...the tar paper will help mitigate and if moisture collects it follows the tar paper down and out the eaves and not drip onto your insulation.
Yes the attic space needs to be very well ventilated ever how you decide to do that (full ridge vent with open eaves say)



My 2 cents for what it is worth

 

[ultrarunner]

We have a 1860 Barn with 14 to 24 inch wide vertical board redwood siding (No batons) with a 80 year old tin roof from with lead washer nails.

The barn is 40 x 60 and summer/winter... never a hint of moisture and no insulation anywhere or wraps or building paper/felt.

Could the condensation aspect be high dependent on local conditions?

 

[bkrgi]

We have a 1860 Barn with 14 to 24 inch wide vertical board redwood siding (No batons) with a 80 year old tin roof from with lead washer nails.

The barn is 40 x 60 and summer/winter... never a hint of moisture and no insulation anywhere or wraps or building paper/felt.

Could the condensation aspect be high dependent on local conditions?

Yes totally

 

[Diggin It]

All that stuff uses energy .... LOTS of energy.

Unless you're planning on living out there or you're Jay Leno with millions in classic cars to store, what's the point? Barns and sheds store yard machines and tools under cover from direct weather. Most older barns are well ventilated and have stood for decades. My shed with a galvanized tin roof sweats a bit, but I don't sweat the sweat.

 

[gregb46]

I built a pole barn myself 2 years ago. There is a product called foil faced bubble insulation that is installed on the roof system then the metal roof is installed on top. I haven’t had a drop of condensation in my building. It is basically bubble wrap with foil on one or both sides. It’s expensive but it does the job. There are other types out there that are foil faced foam. Any reputable pole barn material supplier or lumber yard should be able to help you out.

 

[Barnbuilder]

Gregb46,
In a out 12 years that bubble wrap will deteriorate. It has on every barn I used it on. Just finished putting a ceiling in a very nice barn to cover that mess. I have a thread in here on it.

 

[gregb46]

Good to know. Wish I knew that 2 years ago.