Another metal building insulation question

[recountryman]

I'm still gathering info for my metal building build either a 30x50 or a 40x60. Now looking into insulation I'm in Georgia so hot humid summers with mild winters with a rare cold spell or two. If I go with CCF I would want some type of a radiant barrier installed first on the ceiling prior to spraying or just directly spayed onto to metal? I've read that due to condensation that would be the best option with a foam thickness for 2-3 ceiling and 1-2 one walls for my area. Will be welding and grinding and walls will be open so want to stay away from OCF. Or would ceiling alone be OK if I go with a light color.

Also I know another option not as good but way more cost effective is the batt insulation are these OK for the temps I will see and how long does these last before the plastic backing starts failing apart as I have been in some building that looked like same stuff where they were falling apart......thanks

 

[MrSurly]

Feel free to read my build thread and others where foam is covered heavily.
I did foam and I LOVE it. I used both types.
I used OC above 7' including the underside of the roof metal. I used CC 7' and below for the same reason you suggested (durability).
I can attest to the product's durability in MY use.
Expect to hear some naysaying from some folks who don't have foam, will never have foam, telling you about "voided warranties" and "impossible to remove" foam, "tinderbox" and other OWT.
I have tried to find links to warranty denials, still no luck.
despite the claims that I was "building a powder keg", my building (despite my welding/grinding/cutting projects) has resolutely (again, so FAR) refused to burst into a fireball.
I can't answer whether you *SHOULD* spray foam straight onto the metal (and I even found disagreements between foam suppliers about this). I can tell you that's what *I* did. If it creates calamity in the future, I promise I WILL post it here. So far, three years of Open Cell 5-1/2" under roof in hot humid East Texas, I wouldn't consider any other method, personally.
You SHOULD talk to your metal supplier and find out (try to get in writing) what they say about warranty and foam recommendations.

 

[karoc]

Feel free to read my build thread and others where foam is covered heavily.
I did foam and I LOVE it. I used both types.
I used OC above 7' including the underside of the roof metal. I used CC 7' and below for the same reason you suggested (durability).
I can attest to the product's durability in MY use.
Expect to hear some naysaying from some folks who don't have foam, will never have foam, telling you about "voided warranties" and "impossible to remove" foam, "tinderbox" and other OWT.
I have tried to find links to warranty denials, still no luck.
despite the claims that I was "building a powder keg", my building (despite my welding/grinding/cutting projects) has resolutely (again, so FAR) refused to burst into a fireball.
I can't answer whether you *SHOULD* spray foam straight onto the metal (and I even found disagreements between foam suppliers about this). I can tell you that's what *I* did. If it creates calamity in the future, I promise I WILL post it here. So far, three years of Open Cell 5-1/2" under roof in hot humid East Texas, I wouldn't consider any other method, personally.
You SHOULD talk to your metal supplier and find out (try to get in writing) what they say about warranty and foam recommendations.

What luck I am trying to make a decision,I have read so much information about what is cost effective vs what is best and other ways to do this as a DIY
Mr Surely, I am building place in Hemphill Tx could you provide link to your adventure,I would love to learn from someone with first hand experience. Sorry I am not a computer savy person

 

[MrSurly]

I have read so much information about what is cost effective vs what is best and other ways to do this as a DIY

I would love to learn from someone with first hand experience.

There are many many folks on GJ with experiences to share. There is also a tremendous wealth of information and, yes, it can be quite daunting. Keep reading, use the search function to seek out topics; ask questions, that's why we are all here.
There will be differing opinions and approaches; my way may not work for you. Read, soak it in. No matter your budget, it's a really big deal, building a shop. Getting info and making informed decisions goes a long way to being satisfied with the result.

My build thread is here.

 

[travisn1]

All I have to add is be sure to install house wrap before the sheet metal, then you can spray directly onto that without concerns of moisture/rust.

Oh, and always go for the bigger size barn.

 

[kelpaso1]

All I have to add is be sure to install house wrap before the sheet metal, then you can spray directly onto that without concerns of moisture/rust.

Oh, and always go for the bigger size barn.

I don't think this is good advise. There was a guy on here that did that and the tyvek couldn't hold the weight of the foam and it was pulling away and sagging, especially on the roof.

 

[recountryman]

Feel free to read my build thread and others where foam is covered heavily.
I did foam and I LOVE it. I used both types.
I used OC above 7' including the underside of the roof metal. I used CC 7' and below for the same reason you suggested (durability).
I can attest to the product's durability in MY use.
Expect to hear some naysaying from some folks who don't have foam, will never have foam, telling you about "voided warranties" and "impossible to remove" foam, "tinderbox" and other OWT.
I have tried to find links to warranty denials, still no luck.
despite the claims that I was "building a powder keg", my building (despite my welding/grinding/cutting projects) has resolutely (again, so FAR) refused to burst into a fireball.
I can't answer whether you *SHOULD* spray foam straight onto the metal (and I even found disagreements between foam suppliers about this). I can tell you that's what *I* did. If it creates calamity in the future, I promise I WILL post it here. So far, three years of Open Cell 5-1/2" under roof in hot humid East Texas, I wouldn't consider any other method, personally.
You SHOULD talk to your metal supplier and find out (try to get in writing) what they say about warranty and foam recommendations.

Thanks I have read about your build and it looks great! Thanks for the info.

 

[recountryman]

I don't think this is good advise. There was a guy on here that did that and the tyvek couldn't hold the weight of the foam and it was pulling away and sagging, especially on the roof.

Wow that would **** but does make sense but I have read posts about people spraying it over the batt insulation seems that that would be having same issue?

 

[Marctrees]

karoc - Another member Shovelhead is also building near Hemphill.

Marc

https://www.garagejournal.com/forum/showthread.php?t=456300

 

[travisn1]

I don't think this is good advise. There was a guy on here that did that and the tyvek couldn't hold the weight of the foam and it was pulling away and sagging, especially on the roof.

I've only ever heard of spraying the walls then using blown in for the ceiling. I would think the foam would attach on and between the 2x4's then be strong enough. Interesting though.

 

[My Old Tools]

My building has plastic backed fiberglass insulation. It has been quite effective here in hot humid east Texas. I had the frame wrapped with 4" before siding or roof was added, then a second layer of 8" was added to just the roof.

 

[Toyomech]

We are a spray foam contractor in the mid atlantic so not in your area but I can respond to some points. We have been in business since 1977 and have done thousands of metal buildings. There are so many opinions and wives tales when it comes to spray foam. We are constantly answering similar questions. Obviously a big believer in foam so I wont weigh in on alternatives just installation methods. We have sprayed on Tyvek, mesh, radiant barriers, etc. Our preference is spraying directly to metal. If you use housewrap you will lose one of the big benefits of closed cell foam which is its adhesive property and ability to add strength to the building by locking everything together. Any substrate you do spray to needs to be secured firmly or you wont get good results.


Spraying directly to metal leaves no air gap for condensation or rust to develop. No respectable gauge of metal will warp due to proper spray foam application. In case you ever needed to remove a panel for whatever reason my preferred tool is an oscillating multi tool to outline and a good karate kick. A plumber recently told one of our clients that closed cell was "like concrete"... Its a strong product but its far from being as difficult as concrete to cut. We trim closed cell with filet knives. Happy to answer specific questions about foam.

 

[MrSurly]

We are a spray foam contractor

Glad to get input from the installer side. If you read my posts you will see that I am a proponent of foam and a defender against spurious old wives' tales. Typically I hear the same old saw about how it's *impossible to remove* *voids your warranties* *spontaneously combusts* and other such tripe, invariably from people who have never had foam and never will. I have also found the same mantras repeated as if from *authority* "he's a builder, you have to believe him" while actually he's a builder and a cellulose installer/ promoter, so maybe not neutral. Thanks for chiming in. I wish you'd start a new thread "foam installer question-answer thread" and also look into becoming a GJ supporting vendor.

 

[pmiranda]

Hmm... my metal building supplier is concerned that CC directly on the roof panels (33 feet long!) might prevent them from expanding and contracting freely and could cause them to warp, so they're recommending an underlayment to allow them to move. Is a 3 or 4" application of CC foam that strong, or is the concern unfounded?

 

[MrSurly]

My instinct is that seems preposterous, but I will gladly defer to the experts. What brand of metal does your supplier sell? Ask him or them for something in writing about their recommendations. Not local guy’s off the cuff opinion but the manufacturer’s actual written policy.
Also ask for the same regarding their warranty and foam.



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[Toyomech]

Thanks for chiming in. I wish you'd start a new thread "foam installer question-answer thread" and also look into becoming a GJ supporting vendor.

Thanks I would be glad to answer q’s regarding foam since we get the same set of questions almost daily. Also contacted GJ regarding becoming a sponsor.


Regarding roof warping. In addition to the thousands of metal buildings we have done, we also do spray foam roofing. This is a 2-3” coating of foam on flat roofs with a urethane or silicone coating for UV protection. It is a denser foam 3 lb vs normal 2 lb closed cell used inside. We frequently hear that foam will warp metal or will crack from building movement. Usually claimed by roofers selling alternative products. This is not the case. Our largest roof was 400k sq ft and has been leak free for 20 years. The oldest SPF roof is over 40 years old and still going. In very large roofing projects, between buildings will be an expansion joint for movement.

On a pole barn we have never had cracking or warpage. You can google spray foam roof at texas A&M for a good case study on longevity of foam roofing. Millions of square feet were installed going strong. I have yet to see proof of claims of warping or cracking. These days with the internet and social media I should be able to find tons of examples of what your builder says if it was true. MrSurly has a very good point regarding old wives tales. They keep being told but no one seems to know anyone who actually has real world experience.

 

[Metallitubby]

Subscribing just because I like actual responses.

 

[recountryman]

I think after talking to 3 other people in my area about their buildings I'm gonna cheap out and go with the usual batts since will not be heating and cooling it.

 

[readhead]

As a metal building contractor I can attest to the damage done by spray foam. First let me say that I think spray foam is a great product and does exactly what it says it will.
I have had to repair enough buildings to know that I would not recommend it to my customers. The main problem is that it is a silent killer. You may not see the damage until ten years later but it is happening. The shortest time I have seen is three years but average seems to be 8-12 years.
This is just information from the other side of the equation.

 

[karoc]

We are a spray foam contractor in the mid atlantic so not in your area but I can respond to some points. We have been in business since 1977 and have done thousands of metal buildings. There are so many opinions and wives tales when it comes to spray foam. We are constantly answering similar questions. Obviously a big believer in foam so I wont weigh in on alternatives just installation methods. We have sprayed on Tyvek, mesh, radiant barriers, etc. Our preference is spraying directly to metal. If you use housewrap you will lose one of the big benefits of closed cell foam which is its adhesive property and ability to add strength to the building by locking everything together. Any substrate you do spray to needs to be secured firmly or you wont get good results.


Spraying directly to metal leaves no air gap for condensation or rust to develop. No respectable gauge of metal will warp due to proper spray foam application. In case you ever needed to remove a panel for whatever reason my preferred tool is an oscillating multi tool to outline and a good karate kick. A plumber recently told one of our clients that closed cell was "like concrete"... Its a strong product but its far from being as difficult as concrete to cut. We trim closed cell with filet knives. Happy to answer specific questions about foam.

This neat,and straight from the pros. Question Toyomech, to eliminate condensation problems about how much needs to be sprayed on the under side of the roof? What is the preference CC or OC?
Tough? Heck they make molding out of this stuff such as corbels,I don't know if its the same but it is hard and paintable.

 

[karoc]

As a metal building contractor I can attest to the damage done by spray foam. First let me say that I think spray foam is a great product and does exactly what it says it will.
I have had to repair enough buildings to know that I would not recommend it to my customers. The main problem is that it is a silent killer. You may not see the damage until ten years later but it is happening. The shortest time I have seen is three years but average seems to be 8-12 years.
This is just information from the other side of the equation.

What is happening to the metal,rusting away?

 

[MrSurly]

As a metal building contractor I can attest to the damage done by spray foam. First let me say that I think spray foam is a great product and does exactly what it says it will.
I have had to repair enough buildings to know that I would not recommend it to my customers. The main problem is that it is a silent killer. You may not see the damage until ten years later but it is happening. The shortest time I have seen is three years but average seems to be 8-12 years.
This is just information from the other side of the equation.

OK, I'll bite. any pictures? Description of what you've found? (many times)
teach me. Tell me why "It's a great product" and at the same time "I would not recommend"

 

[readhead]

It traps moisture behind the sheets. It usually shows up as small rust holes in the siding but I have also seen holes in the purlins and girts. The worst part is the siding is glued to the building making removal difficult.

 

[nadogail]

I wonder which conflicting argument to believe.

 

[MrSurly]

Still hoping for pictures, evidence of some kind to support these broad, general claims.
Was this claimed damage associated with closed or open cell foam? Installed directly to painted metal or sprayed on a substrate of some type?
Sprayed onto new metal or onto an existing building?
What percentage of the metal experienced rust? Randomly located or along edges/seams/ridges?
I’m looking for any supporting info...


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[readhead]

I don’t publish pictures of customer buildings. All the problems were related to closed cell. All problems were sprayed directly on new sheeting and secondary framing. Damage is usually random, based on moisture intrusion.

 

[Toyomech]

Karoc: The least we generally spray under a roof is 2 inches. Our preference is closed cell.

Regarding this and most other questions it should be noted that location and climate zone definitely play a role. Open cell may work great in Texas but in our mid atlantic region and definitely in Colorado experiences and practices will differ.

Readhead I wont discount your experience offhand, also you’re in Texas, a completely different climate than I am so maybe there is something I can learn. I can only respond based on our experiences and the little bit I have tried to learn about building science. I would like to ask a few questions though.

Rust needs air and moisture to form. Closed cell adheres with no air gap to metal. If moisture is entering the building how is it getting in? Are fasteners or seams leaking after only 3 years? What if the building was fiberglassed and drywalled, would mold be growing in the walls? What specifically about closed cell foam do you attribute your experiences?

We sell foam so putting aside our experience which could be biased don’t we have enough members on GJ with closed cell foamed pole barns over 10 years old to hear about it? Can anyone add some real world rust issues? I get asked this question routinely, ive heard it said many times by metal suppliers, I’ve just never seen it personally and dont understand how or why it would happen.

To the OP, good luck with the fiberglass. Cost of spray foam isn’t right for every situation. Hopefully didn’t hijack your thread. Will try to soon start a general spray foam questions thread as suggested.

 

[readhead]

Probably a regional thing but very little open cell is used here. Speculation is that the moisture is condensation formed in perfect conditions in very small amounts over a long period. Leaks around windows are another contributor. It is not a fast process. The one that was three years old was window leaks with water trapped between the siding and foam. When removing the sheets on most of these jobs I would notice very small voids almost like bubbles that trapped water.

Let me be clear about one thing. This problem may not affect every building with metal siding being steel or wood framed. I suspect that many buildings have this problem but the owners haven’t discovered the damage. The worst part is the repair. On one building the repair was almost as much as the original building. Fortunately the owners insurance covered the cost.

 

[pmiranda]

So I found a reference to what my roofing guy was talking about:
https://blog.mbci.com/spray-polyurethane-foam-insulation/
A standing-seam metal roof apparently needs to be able to move a bit.
That article doesn't specify an underlayment, but I found other references to using thin fan-fold insulation. It's only 24 cents a square foot at Lowes, but since the sections are only 2x4 feet, I don't know how well it will support the foam given the purlins are spaced at 5 feet. Maybe 4x10 T&G? hell if I know.

 

[Toyomech]

Sorry Readhead i said you were in Texas but you are actually in Colorado. To follow up, if those buildings with window leaks or other leaks had alternative insulation products, lets say fiberglass, do you believe there would have been a different result besides ease of panel replacement? im trying to learn how closed cell specifically either caused the problem or aggravated it and would like your input since your experiences caused you to warn people away from spray foam specifically.

 

[Toyomech]

Pmiranda ill start another thread soon for further discussion as promised, I dont want to completely hijack OP’s thread discussing roof movement especially since hes made the decision not to use foam.

 

[Shovelhead]

Boy am I glad to see this thread and hope the discussion continues. I'm all in.

Need to make a decision within a couple months on how to insulate my next shop.

What baffles me most, and has me very very leery about using foam is the fact that NO ONE can tell me what the RIGHT WAY is. Open cell or closed cell.

There has to be a right way for my location and structure type, period. I get this "it's all up to the customer, either type will work". That's bull $hit.

Ok, carry on men.

 

[readhead]

With a little bit of air movement fiberglass and the area around it will dry out. I don’t believe the foam caused the damage but it definitely had a part in it. I like foam and I think that in time someone will figure out a way to use it on metal. I have seen people try to spray it on tyvek backed metal but unlike wood stud walls the foam just doesn’t have anything to grab onto. I’ve thought about using tyvek and then some how installing the orange plastic temp fencing about about an inch away from the tyvek so the foam would have something to hang onto. Unfortunately I can’t talk anyone into being the first one.

 

[Marctrees]

Chicken wire has been used in that manner.

Good or bad, I dunno.

Marc

 

[MrSurly]

What baffles me most, and has me very very leary about using foam is the fact that NO ONE can tell me what the RIGHT WAY is. Open cell or closed cell.
There has to be a right way for my location and structure type, period. I get this "it's all up to the customer, either type will work". That's bull $hit.

I'll agree on this point as I had the same aggravation and discussions. In talks with the two *most experienced* local sprayer contractors I got "I ONLY recommend Closed cell on the roof" and the other one said "I ONLY recommend Open cell on the roof". Either of them would spray whatever I wanted, but those were their recommendations.
I heard that
1.) a screwed metal roof is GOING to leak
2.) Open cell will discolor and also let the water drip, so you can locate and fix the leak.
3.) Open cell, once wet will *FALL OFF* of the roof.
4.) Closed cell will actively *PREVENT* leaks
5.) Closed cell will HIDE leaks
6.) Closed cell will allow hidden leaks to cause rust and even foam rot.
7.) Open cell will simply dry out, undamaged, once a leak is repaired
8.) Spray foam will VOID your warranty.

The ONLY part I *KNOW* is FACT...is #1. All the rest are unproven, in my estimation.
Concern about #5 & #6 being *possible* led me to use Open cell on the roof. No visible leaks, yet, three years in.

 

[readhead]

Keep in mind that insulators want to sell product. I think that for the most part there is nothing evil going on but their business is to sell jobs. I will assert again that foam is a great product. I, on the other hand, am selling a building that includes a lot of different materials and products. My goal is to provide the best value for the customers money and the longevity of the building. In my experience that doesn’t include foam. I have had people ask for quotes and ask for foam. I explain the issues and tell them I will not do foam and they can decide to continue with a quote with fiberglass or go somewhere else.

 

[pmiranda]

1.) a exposed fastener screwed metal roof is GOING to leak
2.) Open cell will discolor and also let the water drip, so you can locate and fix the leak.
3.) Open cell, once wet will *FALL OFF* of the roof.
4.) Closed cell will actively *PREVENT* leaks from entering the interior
5.) Closed cell will HIDE leaks
6.) Closed cell will allow hidden leaks to cause rust and even foam rot.
7.) Open cell will simply dry out, undamaged, once a leak is repaired
8.) Spray foam will VOID your warranty against oil canning in thin metal

They're all true to some extent, so they're both right

I'm planning on gambling that foam will stick to a water-shedding membrane like Tyvek on the roof panels, which on my build are standing-seam and 1) shouldn't leak, 2) can have noticeable thermal expansion over a 33 foot length that closed cell foam could interfere with.
Tyvek because if the roof does leak it should shed instead of settle in the foam yet any moisture that does get under it should be able to escape.
Closed cell because Tyvek isn't air tight and it seems to give better performance.

On walls, I plan on closed cell directly to metal because I'm less worried about water getting trapped in a vertical space than a shallow angled one, and it is full of holes that I want sealed. Also to seal the top and bottom against critters.

 

[My Old Tools]

I posted my insulation pictures above using plastic backed fiberglass. My builder discouraged the use of foam based similarly to what readhead said. I can say that fiberglass done well is very good insulation. My building is very comfortable. The additional overhead insulation cured the problem I had in previous shops where heat pooled up high and radiated through the roof.

 

[recountryman]

Pmiranda ill start another thread soon for further discussion as promised, I dont want to completely hijack OP’s thread discussing roof movement especially since hes made the decision not to use foam.

I doon't care if it gets hijacked...I'm learning..I find all this interesting.

 

[recountryman]

I posted my insulation pictures above using plastic backed fiberglass. My builder discouraged the use of foam based similarly to what readhead said. I can say that fiberglass done well is very good insulation. My building is very comfortable. The additional overhead insulation cured the problem I had in previous shops where heat pooled up high and radiated through the roof.

I know the people I talked to about there insulation (batts) said same thing that its not overbearing hot in summer and same thing in the winter about coldness. I figure won't do the foam sine wont be heating/cooling it and maybe with the money saved I can buy some more toys!