Metal building insulation...again

[speedracerfx]

I've searched and read, and read, and read, and everyone swears by a different type of insulation for a metal building. I just put up a carport style garage, measuring 28x30x12. I'm in Southeastern PA, so it gets very hot, and very cold here. I do not plan on heating/cooling the building 24/7, only while I'm actually in there working. I do plan on closing the first 8 feet of the walls with OSB. I may or may not close up the rest of the walls at some point later down the road, but most likely not. There is a vapor barrier under the slab. Closed cell spray foam seems like the hot ticket, but some people swear it will rot out the building. Seems like there are similar concerns with foam board and batts too. So what's the solution?

 

[fuggle]

Who says closed cell foam will rot the building? I'm curious. I've never heard that.

 

[speedracerfx]

I've read that in a few different threads here.

 

[rockcrawler]

Mine gets super humid with the closed cell foam insulation. I’ve read many people are complaining about that. Maybe the thought is that the increased humidity will cause accelerated rust. I’m seriously considering A/C now. Really did not want to, but the humidity is getting to me. I’m old.

 

[jmdirk]

That stems from the fact that some metal building suppliers will void the corrosion warranty if you spray foam it. Which like stems from some suppliers not knowing or understanding the long term impacts of it or if the spray foam chemicals could adversely react with the paint and or steel. Probably more of a 'cover your ***' warranty exclusion than anything. I had metal building vendors tell me to just spray foam it.

Either way, you still need a way to ventilate the space to prevent moisture and condensation problems.

 

[bullnerd]

I used blanket insulation specifically for metal/pole buildings.

Google Photos

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[Lastrohm]

We our having our 21'x35', 10 foot walls metal garage done with the closed cell spray. The guy who came out to give an estimate said that it's important to do the spray when the outside temperature is warm so when the hot spray hits it won't cause condenstation like it would it sprayed on a cold panels.

 

[speedracerfx]

Bump. Any viable alternatives to closed cell? I've received two quotes to spray my building, and they're both about $7000 for 2". They'd do 1" for $5k. Yikes. Is it worth doing 1?"

 

[whateverit takes]

I live in NE Florida and recently put up a 30 x 40 metal shop. I installed a shuttered exhaust fan in the west gable which does quite well in removing the heat. I purchased but have not installed 3" bat insulation R-10 custom cut that was $2750 delivered. It came with steel band tape and sheet metal screws for the install. I strongly considered adding a mini split but I won't need it as the exhaust fan along with a floor fan is fine for me.

 

[speedracerfx]

Since spray foam isn't in my budget, I decided to go with foam board. I ordered faced 2" R-13 foam board from Home Depot, and it'll arrive on Saturday, along with 10 rolls of foil tape. I had my building laid out with 4' centers, so this should work out quite nicely. I'm at $2400 with delivery. I'm not looking forward to being on ladder at the 16' peak, but I'll do it to save $4600. lol. The saved money will pay for a mini-split and another bridge jack for the lift.

 

[Bretny]

If your going to vent it what's the point of insulation? I guess this really depends on the temp change and if you care about the metal things in the building.

Many people dont heat there garage until there working in there. Then you have cold metal objects with warm air. This makes condensation. Even keeping the building at 40* really helps. Hell even raising the temp slow helps.

 

[ryanmc]

Since spray foam isn't in my budget, I decided to go with foam board. I ordered faced 2" R-13 foam board from Home Depot, and it'll arrive on Saturday, along with 10 rolls of foil tape. I had my building laid out with 4' centers, so this should work out quite nicely. I'm at $2400 with delivery. I'm not looking forward to being on ladder at the 16' peak, but I'll do it to save $4600. lol. The saved money will pay for a mini-split and another bridge jack for the lift.

I just did this with my 17ft peak i couldnt imagine using a ladder, first i rented a bakers scaffold for 2 days then i found a used one pretty cheap

theres a guy on facebook selling 2” for 20 a sheet delivered i think minimum order is 50

 

[dcg9381]

I've read that in a few different threads here.

You've read it. It likely originates from building manufacturers that want to sell you their "blanket" insulation package. They'll tell you that if you spray foam, warranty is no longer valid, which may be true.

I'm not in PA, I'm down south. But we do these buildings all day long in open cell / closed cell. Both heated and unheated buildings. I've seen some that have been up for more than 15 years (right about the time foam came out). I have never actually seen one failure where foam insulation was blamed as root cause.

IMHO, the "worst case" is that you have a building leak and foam may channel that water to contact the panel... But that's a building compromise issue, not a problem with foam insulation.

Go check out some local airports. Bet you find some hangers that have been up for a while that use foam.

The sheet solution you chose is great..

 

[Hobby_Man22]

I was at the local recycling place and I noticed their building was foamed. Did they color this stuff at some point? That's the second older building I've seen where the from was green. That place had round white patches all over like it was moldy or something. Honestly these buildings do leak. It may take a 70mph sideways rain to do it, but my building is only a couple years old and it will leak under certain conditions. It was also noisy as could be inside that recycling center. Everything they did had an echo to it.

 

[Hobby_Man22]

I never went with foam insulation in my steel buildong because nobody ever answered these questions.

1. Can more foam be added later on if I decide I want more r value?

2. Can a section be scraped off and resprayed if a repair to the building is needed?

3. Will I hear the rain on the roof?

4. How is the noise inside the building? Is every sound magnified because the noise bounces off the walls?

5. Can open cell foam be used in Houston Tx? I was told only closed cell could be used.

 

[theoldwizard1]

5. Can open cell foam be used in Houston Tx? I was told only closed cell could be used.

A sponge is an example of open cell foam. Holds water for a long, long time !

 

[Hobby_Man22]

A sponge is an example of open cell foam. Holds water for a long, long time !

So it soaks up the humidity?

 

[EndlessHydro]

I used these 4x8 sheets of OSB with foam board already attached and it works amazing!!! Hunter panels / HUNTER XCI i think they are a bit pricey but i bought 110 sheets from a contractor that had them left over from a jobsite!

 

[Cobradriver]

Bump. Any viable alternatives to closed cell? I've received two quotes to spray my building, and they're both about $7000 for 2". They'd do 1" for $5k. Yikes. Is it worth doing 1?"

Deleted...

Sorry...

 

[brownbagg]

i did the reqular 2x 4 wall,bats and pylwood on inside. i like to hang stuff off the plywood

 

[bradpac]

My debate is, is 2" of rigid R13 insulation better than 1" of closed cell spray foam?
I scored a storage unit full of polyiso 4x8 sheets and already sold off the 1/2" ones and paid for the 2" ones I have left. I could sell off the 2" ones and make enough to get 1" of closed cell sprayed.

So, should I just keep the 2" boards and put them up or get 1" of closed cell sprayed and seal the building up better?

 

[theoldwizard1]

So it soaks up the humidity?

Yes and holds it next to the metal making it rust !

 

[theoldwizard1]

My debate is, is 2" of rigid R13 insulation better than 1" of closed cell spray foam?
I scored a storage unit full of polyiso 4x8 sheets and already sold off the 1/2" ones and paid for the 2" ones I have left. I could sell off the 2" ones and make enough to get 1" of closed cell sprayed.

Polyiso has the highest R-value per inch of any insulation. The down side is, it is flammable. If it starts to burn, it will run in rivers of fire.

 

[bradpac]

Polyiso has the highest R-value per inch of any insulation. The down side is, it is flammable. If it starts to burn, it will run in rivers of fire.

Polyiso is good R Value, but individual boards lack the air sealing properties of the spray foam at all the edges and corners. Being my most noticeable issue is heat radiating off the metal walls, the bigger R value might be more favorable than the air sealing. The intention is to put liner panels over either insulation to mitigate any fire hazard. Although I'm not sure if a river of fire would be a negative or a positive for polyiso, if your shop is going to burn, make it burn as badass as you can.

 

[chipjumper]

I’m not trying to hijack this thread but I see something not being addressed in the posts: is it better to have the insulation material regardless of style (face/unfaced/board) pressed directly onto the metal exterior panel to eliminate an air gap?
I have a 24x40 steel carport-style garage with 2.25” 12-gauge tube construction. I recently purchased 38 cases of Knauf Earthwool insulated panels with foil on one side. They are 2’ x 4’ and I plan on using foil tape on the foil side to attach them together to make them larger (I have 36” spacing between the vertical tubes). I’m in a cold climate (Central WI). A friend of my suggests putting the foil side facing OUT and directly against the metal and against the DripStop ceiling to take advantage of the foil moisture barrier properties.
My original plan was to leave a 0.75” gap between the metal panels and the mineral-wool side of the insulation panels with the reflective foil side facing IN. My friend says that leaving an air pocket between the insulation and the wall will allow for moisture buildup and would be bad. Is my friends suggestion a sound method to install insulation (directly against the metal wall material)?

 

[Knight511]

The foil reflects radiant heat away from it (this is the reason why I used foam board with radiant barrier facing OUT on my shop because I am more concerned about keeping the shop cool during the summer). The foil can act as a vapor barrier facing either direction. If you want to reflect heat back into the building, you will want it pointing into the building. That said, the radiant barrier properties of the foil only work if there is an air gap between the foil and the next layer which is fine if you are just leaving the foil exposed, but you would need to add the gap if you plan on covering the foil up. I used half inch board and cut the pieces to fit into the purlins (is that the right word for the ceiling?) to hold them in place because this provided me with the .5-.75 inch air gap needed. You can see how I hung mine in the pic below.

 

[Knight511]

It also won't matter which way you put the insulation in because both directions will leave an air gap where condensation can build up because the roof is not flat. the panels need to be air tight from the inside of the shop since the inside will have the warn moist air. If the warm air cannot find its way into the gap to bring the moisture to condensate. That is the purpose of a vapor barrier.... prevent warm air from inside the structure from finding its way into the cold zone on the outside of the structure.

You can use spray foam to close up the air gaps better than tape:

(I called it flash and batt, but it is only flash (poor man's) and batt if you have batts of insulation.)

 

[bradpac]

I started with the 2" polyiso in my building a couple of weeks ago. It's turning out well and I borrowed a buddy's Flir thermal camera and it really shows a difference between the insulation and the bare steel panels.

 

[chipjumper]

I started with the 2" polyiso in my building a couple of weeks ago. It's turning out well and I borrowed a buddy's Flir thermal camera and it really shows a difference between the insulation and the bare steel panels.

Did you press them directly up against the steel?
After reading the greener.gov reports and the zillions of posts on GJ, I think I will press the bare insulation side against the metal siding with the foil side facing IN. The 1.5” insulation panels between the 2.25” square tubing will be held into place by metal foil tape at the edges. I will make the vapor retarded on the inside.

 

[bradpac]

Did you press them directly up against the steel?
After reading the greener.gov reports and the zillions of posts on GJ, I think I will press the bare insulation side against the metal siding with the foil side facing IN. The 1.5” insulation panels between the 2.25” square tubing will be held into place by metal foil tape at the edges. I will make the vapor retarded on the inside.

My wall panels are orientated horizontally so between the purlins and panels they added some hat channels to be able to change the direction of the panels. My insulation is against the hat channel, but leaving a ~1" gap to the panels themselves. Also, my insulation is foil faced on both sides, not sure if that makes much difference or not, but it's what I was lucky enough to find on the cheap. I did not seal it against the purlins in any way, just cut to a tight fit, camera showed no infiltration around the edges and thermal transfer to the purlins wasn't too bad, having that extra hat channel to separate from the panels probably helped that some.

 

[theoldwizard1]

I’m not trying to hijack this thread but I see something not being addressed in the posts: is it better to have the insulation material regardless of style (face/unfaced/board) pressed directly onto the metal exterior panel to eliminate an air gap?

If the air is moving (leaks) all bets are off.

What people don't understand is that it is "dead air" providing the non-transfer of heat ! Fiberglass ha a lot of air in it, but the way it is spun air can not get through. Vapor barriers help this. The indoor ski hill in Saudi Arabia uses about 10' of air as insulation. Of course it is well sealed.

The on!y thing better is a vacuum. Look up Dewar's Flask ( it whiskey).

The best you can do is closed cell foam.

 

[chipjumper]

I just took some photos of the building with the lights dim to show where the metal siding corners and inside eave edge lets air in.
Is there an advantage to spray foam sealing the wall panel u-channels at the edges so that they are “air tight”? I am setting the Knauf 2’x4’ panels against the cold steel siding. The Knauf panels sit against each other and I will be using aluminum tape to prevent air leaks. I’m not sure how I’m going to cover the 2-1/4” square tubes yet; maybe cut excess insulation boards to overlap them or just spray foam over them.

 

[Knight511]

Loctite canned spray foam to seal up these paces. It is closed cell, so it is air tight. Bonus points is that it sets as a pure white foam instead of the yellow foam from GreatStuff. The ouside corners and eaves should have trim in place before foaming the areas.

 

[ASDadam]

Sorry to hijack, but I know its a pain creating new threads everytime.

I'm looking at adding foam board insulation to my walls and also sealing the airgaps as mentioned above with the foam can stuff.

My question is, my budget is limited, am I able to do the 1" foam board do I need to add 1/2 strips and attach them to that and then add my OSB on top or can I attach directly to the metal panel? I'll probably tape the seams to better seal against air.

Also, is there any noticeable difference between R1.9 vs R5 Foam board?

Thank you in advance.

 

[ycgoat]

Unfortunately insulation is out of my budget on my new metal building, I bought the most space I could afford and now have no money for extras, and of course the larger the space the more it costs to insulate. I put up double sided perforated foil in the ceiling with an air gap. I will likely try to do the front wall this summer because it gets direct sunlight. Also plan on adding a large gable fan on one end and louvers to the other, and a wood stove. I have seen condensation recently while puttting the foil up, but it was not dripping. It willl be hard to say how well the foil reduces condensation if at all now that its covered. I may come back in the future and add insulation if my budget will allow.

 

[Knight511]

Sorry to hijack, but I know its a pain creating new threads everytime.

I'm looking at adding foam board insulation to my walls and also sealing the airgaps as mentioned above with the foam can stuff.

My question is, my budget is limited, am I able to do the 1" foam board do I need to add 1/2 strips and attach them to that and then add my OSB on top or can I attach directly to the metal panel? I'll probably tape the seams to better seal against air.

Also, is there any noticeable difference between R1.9 vs R5 Foam board?

Thank you in advance.

If you are using a radiant barrier (foil faced board) and the barrier faces OUT to reject heat during the summer (like my shop set up), you have to have an air gap for the barrier to do its job. If you are only insulating or facing the barrier into the shop, you do not need to have the spacers. In order for a radiant barrier to do its job properly, there must be an air gap (most sources I read say a minimum of 1/2") between the foil facing and the surface next to it.

And yes, there is a difference between R1.9 and R5. Get the R5 if your are just worried about insulating (keeping heat in). If you are just using the radiant barrier to reject heat (again, like me), the R1.9 is fine. The more you want to rely on heating the shop for winter time, the higher the R value you will want. I do not heat my shop at all.... I mean, it was 74 hear today, tomorrow will be cold (40s down into the 20s) but then it will warm back up into at least the 50s or 60s. Heating is a waste where I live IMHO.

 

[hiflyr]

I live in NE Florida and recently put up a 30 x 40 metal shop. I installed a shuttered exhaust fan in the west gable which does quite well in removing the heat. I purchased but have not installed 3" bat insulation R-10 custom cut that was $2750 delivered. It came with steel band tape and sheet metal screws for the install. I strongly considered adding a mini split but I won't need it as the exhaust fan along with a floor fan is fine for me.

I am over in the Pensacola area how did you order the insulation from if you don’t mind sharing.
thanks

 

[PWC Repair]

My vote is closed cell on the walls and open for the ceiling.....if you develop a leak it will come through so you can find it, and it will dry back out.

 

[chipjumper]

Here is what I’ve done so far with the 1.5” R6.5 Knauf board. I used the heavy duty aluminum 3” tape for the panel joints for the walls and 1.5” reflective tape ($14/roll) for seams and against the verticals or anywhere that needs to be sealed. My 30-60k propane tube heater raises the temp from 0 to 35F quite fast even with half the ceiling covered.

 

[Hobby_Man22]

what if you just want to use it as a storage building for your boat or RV? Does it really even need insulation? Will I have issues with condensation on the panels creating rain inside the building?