Enclosed Pole Barn

[rokhunter]

...since it seems many of you have them! I'm getting a 30x40x12 enclosed pole barn built and am planning to get closed cell spray foam insulation. For those who've done that, 1) did you have any problems with the foam expansion and your electrical (wires, plugs, etc.), and 2) would you recommend OSB over the foam or just leave it exposed? I know I do not need the thermal barrier in my area for code purpose. Thanks!

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[GeoBx2680]

With the spray foam have them tyvek the building that way if you ever have to replace metal it can be easily removed. The foam will be stuck to that and not the metal.

I believe more then 2" of foam is considered a thermal barrier

 

[biglefty]

If done right you will have no problems with your electrical boxes or wires. Make sure you have all the outlets you will ever need cause you wont be fishing in new ones later. OSB would be a definite yes for me.

 

[GeoBx2680]

If done right you will have no problems with your electrical boxes or wires. Make sure you have all the outlets you will ever need cause you wont be fishing in new ones later. OSB would be a definite yes for me.

Or you can finish the shed first walls and ceiling. Then pipe all your electrical that way its easier to add later.

Only problem is it will cost more if piping then just pulling Romex

 

[niteshiftfromkc]

I would second the recommendation to have the house wrap put in under the outside skin. If you have time, check out the videos from RR Buildings. They build some amazing barns and even have a video on why they use the house wrap. They rarely use the spray foam with their way of building. It's standard fiberglass in the walls and blown in in the ceiling. https://www.youtube.com/channel/UCWXEQsK3UiHszjwgGN5HUeQ/featured

As far as the osb is concerned, I would spend the money and use 3/4" plywood instead. That way you have something to nail or screw to if adding shelves, places to hang tools, etc. I would also spend the money to have the electrical run in conduit after the plywood is installed.

 

[Workerbee]

Unless you plan to get along without an electrical inspection, you would need to surface mount your wiring. Most run it in conduit. Putting it in behind a wall or insulation doesn’t meet the NEC anymore.

 

[GeoBx2680]

Unless you plan to get along without an electrical inspection, you would need to surface mount your wiring. Most run it in conduit. Putting it in behind a wall or insulation doesn’t meet the NEC anymore.

I wired mine spring of 2018 inside the walls with Romex and it passed inspection. Maybe code has change since then ?
But at the time I wasn't finishing the walls. Soon hopefully I will be

 

[thebicman]

Spray foam will need to be covered for two reasons. Fire code and it will degrade from sunlight.

 

[Workerbee]

Geo, actually thats been code for a long time. In 2012 I did some wiring in an outside building and that was code then. If its attached to a residence as a garage would be, then its fine to put it behind walls. Otherwise its enforced up here and should be everywhere as thats the national code. But maybe your inspector lets things slide? Some do in certain instances.

 

[rokhunter]

Yeah wiring will be done to code, whichever way I go. I've verified the foam doesn't need to be covered for fire code where I'm at because it's not a residential building; UV breakdown could be a consideration though.

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[Poohbear]

My building was foamed before I wired it. I ran conduit & MC cable afterword & set my boxes out for when I get around to putting up 3/4 for finished wall. My building is all steel frame but doesn't matter as in a shop I wouldn't run romex.

 

[GeoBx2680]

Geo, actually thats been code for a long time. In 2012 I did some wiring in an outside building and that was code then. If its attached to a residence as a garage would be, then its fine to put it behind walls. Otherwise its enforced up here and should be everywhere as thats the national code. But maybe your inspector lets things slide? Some do in certain instances.

Its a new post frame building so definitely not a attached garage. Maybe he thought I did nice work. For a Tinner/Sparky

I know what your saying about letting things slide. I do HVAC for a living and every inspector is different even tho they got one code book to follow. But some do also make good judgement calls when you don't have any choice and your bending the code some

 

[North Idaho Wolfman]

With the spray foam have them tyvek the building that way if you ever have to replace metal it can be easily removed. The foam will be stuck to that and not the metal.

I believe more then 2" of foam is considered a thermal barrier

Poly is much cheaper and will do the same thing as it's closed cell so it's not going to breath anyways.

 

[North Idaho Wolfman]

Unless you plan to get along without an electrical inspection, you would need to surface mount your wiring. Most run it in conduit. Putting it in behind a wall or insulation doesn’t meet the NEC anymore.

Are you saying NEC does not allow you to run electrical wire and spray foam over it?
Code number?

The only thing you can't encapsulate in foam are vented can lights.

We are using fire block foam around every electrical box in the house, light switches, outlets, ceiling J boxes and even behind several electrical panels, and yes it's inspected and it passes.

 

[North Idaho Wolfman]

Yeah wiring will be done to code, whichever way I go. I've verified the foam doesn't need to be covered for fire code where I'm at because it's not a residential building; UV breakdown could be a consideration though.

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If your worried about UV killing it, just paint it.

 

[Workerbee]

Are you saying NEC does not allow you to run electrical wire and spray foam over it?
Code number?

The only thing you can't encapsulate in foam are vented can lights.

We are using fire block foam around every electrical box in the house, light switches, outlets, ceiling J boxes and even behind several electrical panels, and yes it's inspected and it passes.

Where did I say anything about wiring in a house? Im saying in any non residential building wiring has to be surface mounted. It cant be behind walls which would come after insulation. Im not thinking you could understand the code But I will get the book out and find the section for you.

 

[skeets]

I understand the code, I would like to see the section, you could be right but the last NEC I have is 68 dont know the new ones are,, that happens when you retire,,lol

 

[D2Cat]

Where did I say anything about wiring in a house? Im saying in any non residential building wiring has to be surface mounted. It cant be behind walls which would come after insulation. Im not thinking you could understand the code But I will get the book out and find the section for you.

This self isolation must be getting to you, pretty snarky comment.

 

[Donystoy]

Your codes must be different than what we have up here in Ontario (Canada).
I recently finished a large non residential two story shop which was constructed similar to residential with insulated walls and drywall throughout. Electrical wiring was done using residential specs inside the walls with no surface mounting. Now if the inside was not finished or concrete with no way to conceal the wiring I would have had to use conduit or armored cable.

 

[North Idaho Wolfman]

Where did I say anything about wiring in a house? Im saying in any non residential building wiring has to be surface mounted. It cant be behind walls which would come after insulation. Im not thinking you could understand the code But I will get the book out and find the section for you.

A pole barn for non commercial use still falls under the residential code, and not commercial codes.

Yes this definition of commercial use or residential use is different in different states.

I was a commercial electrician for 10 years before I became a general contractor.

I have a full understanding of codes and how to read them, thank you very much.

EDIT: I just reread what you wrote to me... Thanks for thinking I'm too simple/ dense to understand a simple wiring code!