Insulating pole barn roof

[Racer_X]

I've been insulating the walls of my polebarn and now it's time to look
at the roof. As you can see, the roof sits on horizontal 2 by 3's, so
there is no soffet or ridge vents. I'll probably put in gable vents
later.

So, I am thinking of putting up something reflective, and then extruded
polystyrene (like I have on the walls) underneath that.

Searching online, I found double reflective foil insulation:
http://tinyurl.com/2ebw5wo

and a reflective radiant barrier:
http://tinyurl.com/2afdg8o

I'm inclined to think the reflective foil insulation will do a better job
because of the air gaps.

So, what do you think? Is there another solution I should consider?
I'm not interested in spray-in insulation. It's not worth the cost for this barn.

 

[nolatoolguy]

I hate to break your bubble, but spray in insalition isnt that much more expensive. We use it in some of our barns. Its well worth it. It works better then reflective foil, and radiant barriers. . Our local home depot doesnt carry it but I did a little reasearch for you http://www.homedepot.com/Building-M...splay?langId=-1&storeId=10051&catalogId=10053 it sais free blower rental with min purchase to. If not there only like 60 bucks a day to rent.

If you are absolutley possitivly opposed to blow in go with solid a sheet type

Heres what I found for that, we havent use the exact same but we got some at a local farm store but a different brand not sold at lowes or hd. Ime pretty sure it was sold at abc building supply to ime not sure exactly.

http://www.lowes.com/pd_304090-210-304090.0_4294858106_4294937087?productId=3122447&Ns=p_product_price|0&pl=1&currentURL=/pl_Insulated%2BSheathing_4294858106_4294937087_?rpp=15$No=0$Ns=p_product_price|0

Now for that sheet type stuff its not that hard to cut. Everyone sais it is but its not. I have used tablesaws to cut it. Jigsaws work well to. They say you dont have to but I put glue on the back to.

 

[Scout Driver]

If you can, put in some soffit or some ridge venting. Something tells me that the gable vents alone may not be enough.

Scott

 

[trbomax]

I think you should have put down the reflective faced polystyrene wrap from Polar before you sheeted the roof.Absolutely stops any condinsation.Another interesting thing about it is that in the winter there is no thermal "signature" where the purlins are,it melts evenly.

 

[Racer_X]

I hate to break your bubble, but spray in insalition isnt that much more expensive.

If you are absolutley possitivly opposed to blow in go with solid a sheet type

Sorry - when I said "spray-in" I was referring to expanding foam.

But, the blow-in fiber insulation you referred to - how on earth would you put that under a roof? On top of a ceiling makes sense, but under a roof doesn't.

 

[Racer_X]

I think you should have put down the reflective faced polystyrene wrap from Polar before you sheeted the roof.

This barn was built about 20 years ago. I just bought the property 2 years ago, so I have to deal with the hand I've been dealt. I think they just stored tractors in it and didn't care if it was insulated or vented.

Now, my brand new 30x60 has all the bells and whistles.

 

[trbomax]

This barn was built about 20 years ago. I just bought the property 2 years ago, so I have to deal with the hand I've been dealt. I think they just stored tractors in it and didn't care if it was insulated or vented.

Now, my brand new 30x60 has all the bells and whistles.

I'd peel the roof,a couple sheets at a time ,and putthe POLAR down. We did that on a 32' square hay barn Ive got,got the inlaws,nephews and went after it.Knocked it out in a week end.Sealed up the gables and ridge,then put forced ventilation in the top of the gables,screens on one end,2000 cfm fan in the other.never a drop of sweat.
That steel looks awful good for being up 20 yrs (IMO)

 

[ebstein]

I've been insulating the walls of my polebarn and now it's time to look
at the roof. As you can see, the roof sits on horizontal 2 by 3's, so
there is no soffet or ridge vents. I'll probably put in gable vents
later.

So, I am thinking of putting up something reflective, and then extruded
polystyrene (like I have on the walls) underneath that.

Searching online, I found double reflective foil insulation:
http://tinyurl.com/2ebw5wo

and a reflective radiant barrier:
http://tinyurl.com/2afdg8o

I'm inclined to think the reflective foil insulation will do a better job
because of the air gaps.

So, what do you think? Is there another solution I should consider?
I'm not interested in spray-in insulation. It's not worth the cost for this barn.

I'd move that junction box, and wiring, and just leave the roof the way it is unless it leaks, then just frame for a ceiling....and insulate the **** outta it...

I personally wouldnt worry about it....that's what we did yrs ago at my sisters place...the old pole buildings were just used for storage and the roofs werent insulated when building....gable vents should be fine....and put a cupola up on the peak...

 

[Racer_X]

That steel looks awful good for being up 20 yrs (IMO)

Heh. You're seeing the bottom side. It's got a bit of surface rust topside.


Thanks for the suggestions, folks.

ebstein - What are your thoughts on turbine vents versus a cupola? There was a hole in the roof from a (now gone) woodburner chimney. Last year I put a turbine vent over it, and the temperature dropped 3 degrees in about an hour. (It's pretty windy here). If a cupola will work better, I like the idea of adding one more hole than about 4 more for turbine vents.

 

[ebstein]

Heh. You're seeing the bottom side. It's got a bit of surface rust topside.


Thanks for the suggestions, folks.

ebstein - What are your thoughts on turbine vents versus a cupola? There was a hole in the roof from a (now gone) woodburner chimney. Last year I put a turbine vent over it, and the temperature dropped 3 degrees in about an hour. (It's pretty windy here). If a cupola will work better, I like the idea of adding one more hole than about 4 more for turbine vents.

the turbine would require maintenance and make noise...the cupola would make the apperence a bit more fance....you could do 2 or 3 cupolas if you wanted...I think 3 decently sized would look good..

 

[willymakeit]

Could use fiberglass batts between the purlins and fasten netting to the bottom of the pulins.

 

[trbomax]

Ive saw cut 2" sheet foam to fit between the top truss chords,then permanantly attach them with 3"screws and fender washers to the purlins.This still maintains a vent cavity,but does not address the issue of condensation on the bottom of the steel,which will happen.At least when it does "rain", it will fall on foam which will not become waterlogged.

 

[rwfabworks]

Spray foam all the way

 

[denis4x4]

I used a spray ON foam that equals R-20 over about 600 SF of shop space in my converted barn. Doesn't look all that neat, but it gets the job done and the best part was that a crew came in, did the job and was out of here in six hours for $1200. Also added some strength to the structure.

 

[trbomax]

The thing that bothers me about spraying a wood/steel building is that the area between the top of the purlin and the steel is still uninsulated and as such will still collect condensate.This "pocket" has nowhere for the moisture to go except into the wood,which is sealed all around as well.Same goes for where the screws penetrate.Over a long term,I wonder about rot forming, much the same as it does in a wood boat that has had the bottom fiberglassed.

 

[ebstein]

what are you looking to do with the building? is the whole thing going to be shop? is there 2 seperate bays/rooms where you could have like a 30*30 shop then a wall, then another room thats like 12*30? Then you could just frame for a ceiling, and insulate with blown in cellulose, and not worry about ventilation cuz you could have the little room/bay not heated and the big one heated...I'll look tomorrow and see if I have some pix of what I'm talking about...

 

[tiresmokindad]

I've been insulating the walls of my polebarn and now it's time to look
at the roof. As you can see, the roof sits on horizontal 2 by 3's, so
there is no soffet or ridge vents. I'll probably put in gable vents
later.

So, I am thinking of putting up something reflective, and then extruded
polystyrene (like I have on the walls) underneath that.

Searching online, I found double reflective foil insulation:
http://tinyurl.com/2ebw5wo

and a reflective radiant barrier:
http://tinyurl.com/2afdg8o

I'm inclined to think the reflective foil insulation will do a better job
because of the air gaps.

So, what do you think? Is there another solution I should consider?
I'm not interested in spray-in insulation. It's not worth the cost for this barn.

I think you already did a great job. I am also planning to install the air gaps. I hope that it will work too.

 

[r.turner]

I prefer spray foam if money available, vinyl backed post frame insulation too.

 

[TrustJesus]

Hello
I am in the process of insulation my pole barn, specifically the walls. My pole barn seems very similar to yours. The outside is metal, then wood framing attached to 4x6 poles, then some additional wood framing (I'm guessing for finishing with drywall or something). Anyway, for the walls I was thinking of putting in extruded
polystyrene as you did. Did you put fit them in place between the girts (butted up to the metal) or did you simply put these over the girts? Does that make sense? Did you use a vapor barrier (like plastic sheeting) on the walls? Any help would be greatly appreciated.

Steve