# Insulating a Steel-Frame Shed Near Miami



## carpdad (Oct 11, 2010)

That doesn't look right. I see vapor barrier and fiberglass insulation from outside, meaning there is another wall outside for sheathing. If air conditioning, you need as much insulation as possible. Even in nj, they're called for at least r19. Usually 2x6 wall. R40 or better for roof. That is 2x12 roof, if with fiberglass. XPS foam boards do better but not significantly. You need as much space for insulation as possible and that image shed frame does not provide. AC and dehumidifier, so this shed can be "configured" for less ventilation, but what you are planning is almost a walk in fridge in restaurants or such and it will be very high cost to maintain.


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## mri (Aug 6, 2019)

Thanks for your reply, carpdad.

What you are seeing is the inside of the shed. On the outside, there is Hardie Siding, next is plywood, under that is the insulation you see. It is the manufacturer's insulation with an airtight treatment.

On those metal studs would go my sheetrock. I am asking if this airtight insulation treatment is correct for my location and whether I can put additional insulation in the wells before applying my sheetrock.


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## mri (Aug 6, 2019)

Unfortunately, I misunderstood your response, carpdad. I just rewrote my entire reply to find that it could not be edited after 30 minutes. I will try my best to remember what I rewrote.

On the outside is Hardie siding panels, then plywood, then the insulation then the vapor barrier. My biggest concern is the technique. Airtight vs ventilated. Secondly, I would like to have as much insulation as possible. So, I am wanting to know if I can add more in the wells without creating some sort of moisture trapping problem. This could be foam board or unpapered fiberglass, I guess. (And I am only guessing, as I am trying to learn and I am in no way familiar.) 

I will need to condition the air to about 80 degrees in summer and use the dehumidifier in winter.

So, I am gathering that you think I need more insulation, not that the method used would cause a moisture problem?


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## mri (Aug 6, 2019)

sorry duplicate post


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## Bud9051 (Nov 11, 2015)

Hi Mri, love your hairdo.
That shed design must be coming from a colder climate. In your location any vapor barrier would be outside of the insulation. Some questions.

1. What will this shed be built on, slab, foundation, or wood deck on blocks?
2. Have you checked local requirements given you will be conditioning this space. Will it be wired for electricity?
3. I'm assuming heat will be electric?
4. Any windows?

Bud


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## mri (Aug 6, 2019)

Hi Bud,

My hairdo comes from trying to figure out what the heck I need to do to get my shed right! LOL!

These steel frame sheds are built locally here in Florida for use in Florida by a shed manufacturer: https://sheddepotsheds.com/

I am not even sure I want the steel frame shed. I'll also be checking on a wood frame shed. 

1) I am using a concrete slab to put the shed on, but I will have a floor.
2) I have been to my local building department. I am not likely discussing my air conditioning plans. People down here are overly worried about people renting out sheds as living space. So, they immediately jump to limit whatever you want to do. I asked if I could have electricity and was told, "NO!" Then I asked what if I want to see inside my shed at night or plug in a drill, or charge my electric mower or e-bike? Sad that in this day and age we'd be forbidden from using electricity! Then I was told I could have electricity for a light and plug--sheesh! The air conditioner will just be a window unit. Not telling anyone about it. I need to store my late husband's collections as my bedroom looks like a storage unit! And I also have stuff in climate-controlled storage that I pay for. I just want it to be safe and dry and my shed to look attractive from my house view.
3) It will have electric. 
4) It will have two windows and probably french doors. I have attached the picture of the style I want. 

Thanks for your response, Bud!


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## Bud9051 (Nov 11, 2015)

You might want to request a couple of bids from contractors to build one on site. Using wood framing makes insulation easy. Hard for me to advise as your location has many different requirements from way up north.

You sounded like you could do some added work like adding insulation and maybe the sheetrock and a wood framed unit makes that easy.

Building one like the last picture is a one man job, similar to my last one so I know and I was 68.

Check lumber yards and ask around for a small or part time contractor.

Bud


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## mri (Aug 6, 2019)

I will check out that possibility. But, I would have to hire an engineer to design it. If it's not Miami-Dade County approved it needs to become approved by an engineer. 

The other shed I am looking at is wood. Steel, however, eliminates termite problems, which are only a ground problem in the north. But they fly around here. 

This is a tough question and no one seems to agree on answers. Thanks for the input!


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## carpdad (Oct 11, 2010)

I don't think I can answer. Not for living but to store things in mint condition? And why AC? Dehumidifier maybe, but you can also use large plastic bins that you can tape shut. Throw in a bag of air driers. The metal shed in the image is insulated but doesn't show how much. It looks like plastic sheet is outside, but it could be encapsulated insulation as well. Based on the photo itself, I think, it may have about r10 insulation, even if the metal studs were about 5" wide? R19 goes into 5" wide walls. Even if you got electric there, smallest window ac can become iced because even that could be too powerful for a small space. Same with dehumidifier. Outdoor wood sided sheds are also vulnerable to bugs and gnawing pests. There are burrowing bumble bees, wood peckers, carpenter ants. Chipmunks, mice and squirrels are checking 24/7.:smile: 



Such factory made shed could be expensive and insulation may not be as tight as the image shows. Your cost could be about the same if you hired a carpenter to build you a wood shed, as bud suggests, and it will be more flexible in how you can condition and use it.


Also, you can't store things in a shed as much as you imagine. It's only about along the wall since you need room for access and such. 



If your collections are precious to you, it would be best if you can find a room in the house?


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## mri (Aug 6, 2019)

Hi carpdad,

Thank you for all the consideration you have given my project. I am not so much keeping things in mint condition as creating a space to hold my sentimental treasures so that I can visit them, as well as to store odds and ends like furniture and building materials.

I am skeptical and cautious regarding contractors. In my experience, I have come across too many people who have learned their trade not using best practices. I have watched Lowe's videos where tile thin-set is being improperly applied. I like to understand what needs to be done before I hire anyone. So, even if I go that route, I will still need my questions answered first. At the very least, I think I will need to consult an engineer. I am no closer to understanding whether Florida requires a ventilated or non-ventilation insulation method. 

Thanks for your help!


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## Bud9051 (Nov 11, 2015)

" I am no closer to understanding whether Florida requires a ventilated or non-ventilation insulation method."
As far as I know either method can be used, however there are requirements to doing it correctly. Here is a related like that explains.
https://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation

Bud


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## carpdad (Oct 11, 2010)

Shelf along the ceiling, example, makes room for display. My mom used to display the dishes on such, although I had to dust them:smile:. Building materials, if in pieces, are not much use, so expensive storage is not cost effective.


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## Porsche986S (Dec 10, 2017)

My 2 cents: Build the shed with the same proven techniques of a house , meaning a concrete slab and build up on site with conventional wood studs or metal studs . Space the studs 16 " or 24 " whatever meets your building code . I would do OSB or plywood on the exterior then house wrap then the finished siding of your choice . I am not familiar with how to properly vent that style of roof that you want , a more traditional 4/12 pitch roof you would add soffit vents and a gable vent . You are in sun city! That sun is baking on that roof most of the day so you have to be able to get rid of that heat .

I assume you have a termite bond on your home ? Call the folks you have the bond with and have them treat the shed . For wall studs I would go 2x6 so you can get decent R value insulation . Stuff as much insulation in the attic/roof space as possible and maintain good air flow . With the house wrap , good insulation and proper ventilation you will be able to condition the space quite well . If you can't or don't want to have a traditional roof line/ventilation then I would suggest having closed cell spray foam shot on your roof structure . The goal obviously is to keep radiant heat from the sun out of the structure .


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## mri (Aug 6, 2019)

Okay, so I have found my answers and figured I would put them here for anyone interested: This article and the one linked in it will provide a basic foundation for vented vs unvented, hot vs cold roofs. Times have changed. https://www.balticexteriors.com/hot-roof-vs-cold-roof-to-vent-or-not-to-vent/ I also recommend watching


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## Bud9051 (Nov 11, 2015)

To be fair, that was written my a company selling their products and services. To that end the information is not complete and avoids some of the negative aspects of a hot roof. But, I'm not going to get into a long thread debating my comments. The link I posted in #12 is from a reputable company who has nothing to sell.

Bud


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## mri (Aug 6, 2019)

Hi Bud,

I understand there are advantages and disadvantages to both types. Leave it to me to leave no stone unturned in my quest for scientific information. I chose that article because it's detailed and gives a link to a great article about vented vs unvented. But I forgot to write the recommended videos in my last post. I really like the information presented by Matt Risinger, whose videos I have been consuming a lot of lately. He has plenty on air-tight construction. This one is my particular favorite: 



 And then there is Joseph Lstibuerk, and engineer who explains the physics associated with vented and unvented attics. He seems to prefer vented, but he appreciates that there are times when unvented is needed. 




Your mileage may vary. But, I wanted to put these videos as I posted with half my sentence unfinished last time.


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## mri (Aug 6, 2019)

Oooo, I lied. Looks like Dr. Lstibuerk would go with unvented. This is Risinger interviewing Lstibuerk. Good stuff.


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## Bud9051 (Nov 11, 2015)

Dr Joe is certainly a great source of information but even advice from the experts needs to be applied to each home in each situation. In your case it is a very small conditioned space so no need to go crazy. The final metric for how well a space is insulated is the energy cost, in your case mostly cooling. The difference between a good insulation job and an extreme insulation job is probably about a $20 bill per year and calculations can be done to add more confidence to that wild guess. These types of calculations are done to see if the added cost of going super is justified by the increased savings. If improvements were to cost $2,000 and the savings would be $20 per year, better to invest that money elsewhere, that would be a 1% return on investment (ROI).

One word of caution, tiny spaces have a problem that even the smallest equipment is too big so it runs so little the air doesn't get circulated that often. In fact, for living spaces, they add outside air for ventilation. It seems ironic at times to go crazy air sealing a home to end up adding holes (fans) to bring in outside air. In a full house it is necessary for air quality.

Enjoy and do let us know what you finally go with.

Bud


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## mri (Aug 6, 2019)

Thanks for that tip, Bud.

You know, I'm not really worried about the cost savings. I have no control over what the shed builders do or the way they do things. I was worried about condensation, mold, etc. I was getting just bits and bobs of info all around the internet with no real explanation of why anyone was doing anything. And I am like Agent Mulder when it comes to trusting anyone. So, I just needed to understand the whole concept before I make my decision. 

I didn't like that steel shed manufacturer's customer service. So, I am now getting a wooden shed with thermo-ply under the Hardie panel and under the metal roof. 

I am thinking maybe I will use great stuff foam and some foamboard to achieve an airtight insulated ceiling. I am hoping that will be the right thing to do to avoid any condensation inside the roof. If anyone doesn't think so, just let me know. Thanks!


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