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Insulation of pole barn. Radiant barriers? direct foam to metal a problem!
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fastline1
Posted 8/3/2015 13:50 (#4714107)
Subject: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


I am doing some work on designing a building for myself. I have realized in research that direct foam to the metal sheeting is a problem! The main issue is moisture. It will get in there, then no way to leave!

I intend to do fiberglass batts and likely looking at a house wrap product over the framing to get a quality air seal.

One of the biggest question I have had for some time is all the building OEM's recommendation of this bubble wrap crap with foil back. Just talked to one claiming an R-11 with it!! LOL, LOL.....

I explained the concerns I have with "thermal bridging" in which heat conduction from the contact of the sheeting and foil means the foil is going to heat right up, regardless of how much radiant it might reject. Then there is the issue with the foil becoming dirty over time. Shiny reflects more than dirty. Then there is the understanding that radiant heat works by transfer of heat, through a space, without heating the air. IE, you gotta have an air gap to reject radiant!

There will be next to no air gap in there.

So is there anyone here that is using a wrap/batts on their building or one with the radiant foil stuff?

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ag4life
Posted 8/3/2015 14:51 (#4714167 - in reply to #4714107)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!



Southern Illinois		what about house wrap then spray foam applied to it instead of directly to the metal? that is the direction I want to go but need more info. There is alot of it going on here
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fastline1
Posted 8/3/2015 14:59 (#4714173 - in reply to #4714167)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


For me, it comes down to price, aesthetics, and modularity of the walls afterwards. Very easy to remove glass, change things, etc. Foam is a pain for that and looks horrid unless it is covered.

I guess for me, fiberglass with a nice plastic barrier on the inside will look decent. If foam price was comparable and I was going to finish the insides out, I might reconsider.
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ag4life
Posted 8/3/2015 15:02 (#4714177 - in reply to #4714173)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!



Southern Illinois		the house wrap was the builders idea to keep the foam from sticking to the metal so if you had to remove a piece the foam would not be stuck. I like the way it stiffens up a pole building, especially the roof which I really want to do as well
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Chuck
Posted 8/3/2015 15:24 (#4714194 - in reply to #4714177)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Wolcottville,Indiana		Plus one house wrap, one inch of closed cell foam and then fiberglass, If money no problem forget the fiberglass and just fill with closed cell foam, my one ct Chuck
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tx68
Posted 8/3/2015 16:35 (#4714279 - in reply to #4714194)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!



Ontario		Our shop was sprayed directly on the steel in 1975 and it has been fine ever since.
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fuelfarmer
Posted 8/3/2015 17:15 (#4714319 - in reply to #4714279)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Virginia

I have not used this stuff yet. R value is not a good indicator of insulation value.

 

http://www.thermalbuildingconcepts.com/

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boog
Posted 8/3/2015 17:20 (#4714323 - in reply to #4714279)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!



We were going to put foam board the closed cell foam on our new building but after talking to a couple insulation contractors we sprayed the foam directly on the metal. Not sure what the OP is worried about moisture getting in as the closed cell will seal any leaks. Plus the closed cell will strengthen the building more than a wrap will. We went with 2 1/2" of closed cell foam, which wasn't much more expensive than 1 1/2" of foam board & 1 1/2" of closed cell foam. Building is 80x120x18 & has two 60' 175,000 btu radiant tube heaters. Used less propane to heat it than it did to heat our old shop 52x50x15', which has bat insulation & is also heated by radiant tube heat.
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fastline1
Posted 8/3/2015 18:23 (#4714398 - in reply to #4714323)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Boog, can you share specifics on how the old shed was built?

The main issues I am finding is people did not used to consider an air seal on the back side of the fiberglass. And, for that matter, even the interior side, attention was not that great on a good seal. It matters.

I'm not blind to the performance of foam BUT I am considering other factors. What happens when I need to replace the roof due to hail? That will be fun. What happens when a stitch screw leaks? How you gunna find that? How bad is the damage by the time you find it? There is also the interior look of plastic backed batts vs foam. I am not finishing the interior right now.

That does not account for the expense. Glass costs approx 1/4 as much as foam.

Despite the knocks to glass, (and some well warranted) if being used correctly, it can work. The main issue I see with glass is the inherent open cell network which can cause convection currents. A proper air seal can minimize that but I am still poking around for non-biased data! All the claims that glass sucks are on sites that are selling foam, radiant wraps, etc. You cannot gather credible data there!
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bellyacre
Posted 8/3/2015 19:39 (#4714521 - in reply to #4714398)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


SWMN		Neighbor has a pole barn built in the early eighties for hogs. It was foamed direct to the steel. No moisture/steel issues on the inside, but the galvanized roof is rusting on the outside along with some tree/storm damage. Thinking maybe removing the screws from the roof and using dynamite to break the sheets loose from the purlins. Any idea how much dynamite it would take to shake things loose without damaging the structure??? I would highly recommend using house wrap between steel and foam!
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cropdude
Posted 8/3/2015 22:32 (#4714961 - in reply to #4714521)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!



NE SD
bellyacre - 8/3/2015 19:39

Neighbor has a pole barn built in the early eighties for hogs. It was foamed direct to the steel. No moisture/steel issues on the inside, but the galvanized roof is rusting on the outside along with some tree/storm damage. Thinking maybe removing the screws from the roof and using dynamite to break the sheets loose from the purlins. Any idea how much dynamite it would take to shake things loose without damaging the structure??? I would highly recommend using house wrap between steel and foam!


Up here quite a few contractors are putting OSB under the steel. Strengthens both the structure and the steel.
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boog
Posted 8/3/2015 21:23 (#4714774 - in reply to #4714398)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!



The old shop was built in 2000. Has 6"x10' wide bat insulation then visquene (sp?) , 21" blown insulation in the ceiling. Insulation was done by a commercial insulation company. 3/4" plywood on bottom 8' & metal on top 7'. One reason I may not be seeing the cost differences is that we priced everything done by contractors.

Edited by boog 8/3/2015 21:26
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JDEEREMAN
Posted 8/3/2015 22:45 (#4714986 - in reply to #4714398)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Eastern ND		When You consider that the plastic air barrier You put on after the fiberglass is going to be punctured by thousands of staples, then thousands of nails/ or screws when You finish the walls, that adds up to alot of holes. Probably the size of a 18"X18" window being open. With closed cell foam sprayed on the steel, or on Tyvek house wrap, the result is no air movement. Zero. That in itself adds alot to the R-value. You will have alot of problems with leaving any insulation job open without a covering. The staples holding the plastic will eventually start tearing out. But then you would be able to watch the plastic vapor barrier "breath in and out when the wind blows, or You open the door.

Remember, good insulation does NOT cost, it PAYS you back EVERY year.
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fastline1
Posted 8/4/2015 00:00 (#4715091 - in reply to #4714986)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Boog, I am curious, was the interior plastic sealed? Like air tight? Was there anything behind the batts or just put right against the sheeting? Was the cellulose covered at all?


JD, I probably have not detailed the interior product over the batts but it is an adhered product tot he glass and is very durable, with a type of polymer threads in it for strength, foil back, and flaps on the edges for sealing. I would only install it with plastic washer finish nails, then cover every seam with their seam tape. I realize any puncture could be a problem so that will be considered.

I also have a slick way of installing glass I figured out some time ago by dropping the air pressure in the finish gun and just barely tap in a few finish nails on the inside of the stud space before glass. The finish nails lock the batt in. technically, stapling is not even required.
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WTW
Posted 8/4/2015 00:11 (#4715096 - in reply to #4714107)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Winkler, Manitoba Canada		Our pole barn shop wall has Tyvek on the outside just under the steel, 1.5" of foam between the outer wall strapping, 5.5" of fibreglass between the poles, and another layer of foam between the inner wall strapping, with a well sealed inner vapor barrier. Ceiling has the vapor barrier tied into the wall vapor barrier with blown in fibreglass in the attic. Fairly tight building with low heating requirements..


Edited by WTW 12/18/2020 00:06




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JDEEREMAN
Posted 8/4/2015 06:33 (#4715243 - in reply to #4715096)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Eastern ND		Looks nice. But, what was the cost / sq ft? And the projected R-value? I think that spraying 2" - 3" closed cell foam costs about $1/ sq ft / inch or less, and that is all the insulation required. Installed total turn key insulation. Just finish the interior. No vapor barrier, and all the extra labor, glues, staples, seam tape,cutting, waste, leftovers, air leaks.......

Attic insul could be applied after the ceiling is installed, just spray to the top side of the ceiling sheeting. Really strenghtens the ceiling and seals the building. Just make sure the attic ventilation is excellent.
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WTW
Posted 8/4/2015 08:11 (#4715445 - in reply to #4715243)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


Winkler, Manitoba Canada		I have no problem with foam insulation, and if properly installed is a premium product. There are however, two significant drawbacks. The cost difference was significant. At the time I think foam would have been more than double, I believe closer to triple. Timing. This project was done in winter with no heat. I believe foam needs to be done in summer, or have significant artificial heating.

Theoretical R value in the walls is around R33.5 but would be somewhat less than that due to the purloins which are offset somewhat. Attic insulation is around R40. We are heating the 50' X 76' X 18' high building equipped with 30' bifold door, and 14' overhead door shop with a 10kw boiler.
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fastline1
Posted 8/4/2015 11:34 (#4715725 - in reply to #4715445)
Subject: RE: Insulation of pole barn. Radiant barriers? direct foam to metal a problem!


A few things. I am still looking for complete studies on batts to ensure I have my ducks in a row.

The main reasons for me selecting glass is cost, appearance, modularity, and ROI. Also, I think some consider it tougher to install, and I am sure I will spend a little extra time BUT I really don't think people consider dimensional buildings. EVERY stud space should be the same if you built with care. Even not, go measure and have them precut. it will cost me 1/10 of a penny/sf to have mine precut and ready to go... They just feed the product out and chop.

As well, My methods of air gunning finish nails inside the stud spaces is HUGE! Reason is you get a piece up, then fight it keep it in place. With the finish nails, they lock the batt in place.

Glass is clean work. No big mess all over.

As far as costs, consider this. closed cell foam is at least 3x the cost but lets go with that. That is assuming the SAME R value. 2" foam roughly = 4" glass with vapor/air barrier. Assume 10k sf. Foam is $1/sf so that is $10k. that wound make glass $.33/sf so $3300. That is $6,700 more to insulate to the same rated R value. Now, where are you located? heating days? Around here, maybe 3mo of heating. Lets further assume the foam will drop your energy costs by $100/mo. That would be an ROI of over 20yrs!

I am willing to wager that within 20yrs, something new will come out.

Now, I am NOT saying foam is a poor choice! Just saying there are circumstances in which glass is still a good choice. The further reality is I can get R-19 walls for a 1/3 the cost of R-12 foam. So even if you have to derate the glass for convection losses, if there is a good air barrier on both sides, you may very well be able to perform on par with foam or better!

Obviously if you live way north with temps hovering 0F or less, foam becomes a better move!

What I have to consider is my radiant heating will run very affordably so cooling becomes the bigger question because electric will be needed for the geothermal heat pumps. However, I am working on some green tech that will use good old solar for cooling!
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