[ARCHIVED THREAD] - 12x32 shed for office space. Need best insulation / heating & cooling ideas (Page 1 of 3)
Posted: 11/26/2022 11:13:32 AM EDT
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We are putting one of these on our property next to the house for my wife's office and so I can do some freelance photography (mini studio). She is sick or working in the house (we have a small home) and she is in MS teams meetings all day long. Wants an open space / background that is not our bedroom. We paid extra for 3" foam under floor and real insulated house windows. We need to insulate, run electric (will put in box with RV receptacle to plug into barn). I want to insulate with the best option and also heat. Our home is Solar with batter backup so it has to be energy efficient. Possibly a small wood-stove in addition to other heating options. I run a surplus on electrical during the daytime (even in winter). In horrible weather we just need to keep the shed 50 degrees (for computer monitors and stuff) Will be dry. Not sure I should post here or the homesteading / survival forums? I'm on 40acres so this will look small on our property.  Ours is just like this one (not same color) and should arrive in two weeks. These are non permanent on skids. We will place on pavers. Attached File Attached File Attached File |
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Closed cell spray foam is great insulation, air seals any gaps and it can make the whole unit more rigid. You really only need 2-3 inches. It is more expensive, but imo, worth it. If you want great info, checkout "spray jones" on youtube. For heat and cooling consider minisplits. With variable speeds they can be very efficient. Too late |
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Spray foam and a window unit will do great. My mother in law is a florist and needed a larger flower cooler. My BIL and I insulated a 10x15 shed with foam board and spray foam, then added a small window unit, and I DIY'd a copy of a coolbot to trick the AC into thinking the room is hotter than it really is so it cools more. Currently have it set to 45F and it has no problems maintaining temp in GA summers. We bump it down a little when we need giant fridge space for any reason. Insulation is key - make sure you have no air gaps!! |
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Quoted: One of those tiny wood stoves would be neat, but your wife might not love the idea of waiting for it to heat up and attending to the fire. Still, it'd make it cozy in there! https://s3-us-west-2.amazonaws.com/usedphotosna/87816042_614.jpg Oh cool, yea we currently heat the house with wood, so not a problem. This may be a nice addition. |
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Quoted: Maybe need to augment the heat some in Wi.? the mini wood stove that was posted above possibly. If it's in the negatives she can work from inside the house. we get weird weather. I have snow on the ground and I was in a T-shirt today. But yes in deep winter it gets really cold. |
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Quoted: the mini wood stove that was posted above possibly. If it's in the negatives she can work from inside the house. we get weird weather. I have snow on the ground and I was in a T-shirt today. But yes in deep winter it gets really cold. Quoted: Quoted: Maybe need to augment the heat some in Wi.? the mini wood stove that was posted above possibly. If it's in the negatives she can work from inside the house. we get weird weather. I have snow on the ground and I was in a T-shirt today. But yes in deep winter it gets really cold. What are you going to do underneath? |
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Quoted: Oh cool, yea we currently heat the house with wood, so not a problem. This may be a nice addition. Quoted: Quoted: One of those tiny wood stoves would be neat, but your wife might not love the idea of waiting for it to heat up and attending to the fire. Still, it'd make it cozy in there! https://s3-us-west-2.amazonaws.com/usedphotosna/87816042_614.jpg Oh cool, yea we currently heat the house with wood, so not a problem. This may be a nice addition. I'm a wood stove all the things type guy, but I might consider a pellet stove here. Especially since this will essentially be your wife's she shed. Pellets are easier to deal with, cleaner, can regulate heat better than a regular stove, and cost similar (ton of pellets/vs cord of hardwood). IMO it would be a nice convenience item. |
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closed cell Spray foam. Floors, walls, ceiling. Mini split and that little stove would work great. I suggest looking into hrv/erv systems and putting a small one in to supply fresh air and stay efficient. If you use a 50 amp rv plug this will give you the ability to put a standard 240v breaker box inside to supply power to everything. If you use a 30 amp plug your going to struggle to find a mini split that is 120v and large enough for your needs. |
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Spray foam is good but expensive. You might not be able to get a spray foam company out there for such a small job. I'd use regular fiberglass. Before you fiberglass it, I'd use spray foam in a can to seal everything. Install fiberglass batts or maybe rockwool batts. Then, cover the inside with 3/4 foam sheets. 1 inch foam sheets if you are covering it with anything other than drywall. I'd probably use polyiso sheets if they were an option. XPS if not an option. Tape all the seams. It's a small space so with an insulated floor it would be plenty of insulation and shouldn't be expensive to heat and cool. I'd probably put a small heat pump mini split and a through the wall propane furnace for heat and cooling. |
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Quoted: Maybe need to augment the heat some in Wi.? That's what I was thinking. I have not heard that the mini-splits have gotten that good yet. So...the little wood stove might be a must? ETA: Some of the folks who renovate school buses into RVs do the spray foam themselves. I don't know any details, but I know you can do it. PPE is essential for this. |
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Code requirement for wall insulation was R19 (5.5" fiberglass) in the mountains of Colorado. (Fraser, CO Icebox of the nation) Close cell foam is 6-7 per inch but products vary. Electric hydronic baseboard heaters would work, Forced air may dry the air too much. |
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For those type of building without a vapor barrier, i would use batt insulation. Foam, especially closed cell foam is great, however it will trap moisture and eventually rot the framing. Those doors and windows aren't nessisarily the best installation. You might have one that's done correctly and will last decades, or you may end up with rot from an incorrect installation after a couple years. Foam would just make replacing the siding more difficult. |
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Quoted: That's what I was thinking. I have not heard that the mini-splits have gotten that good yet. So...the little wood stove might be a must? ETA: Some of the folks who renovate school buses into RVs do the spray foam themselves. I don't know any details, but I know you can do it. PPE is essential for this. The Mitsubishi hyper heat units are speced at 76 percent of rated heating capacity at -13 degrees. |
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So you have R15 in the floor? Code for floors in a home (cantilevers or bonus rooms) is R30. In a shed that size id probably feel OK with that R15. Is it protected by anything? Are walls 2x4? Code is R20, so if you want to get near that for efficiency youll have to spray foam—closed cell. If 2x6: batts and a sealed vapor barrier since you are heating cooling and habitatating to some degree. Id do a heat pump mini split and if it gets too cold during our -26 week or two every winter supplement with an electric space heater. But if that cuts your solar independence too much then wood stove and add some windows to open in the summer? |
| Just as a different “off the grid” solution….a coworker’s family had an off-the-grid “shed” (really a nicer cabin than the house I live in, just small - like 12x20, 2 stories) they use as a hunting camp in northern Michigan. They’ve got a solar system, but also have the “shed” and the “outhouse” plumbed with propane, and have propane lights and small propane faux-fireplace heaters. We went bird-hunting there in October one year and it was well below freezing, and just the pilot lights from the heaters and the mantles from the gas lights was more than enough to heat the entire “shed.” We never had actually turn on the heaters. We had to open the doors when we did any cooking because it would get too hot. |
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Quoted: So you have R15 in the floor? Code for floors in a home (cantilevers or bonus rooms) is R30. In a shed that size id probably feel OK with that R15. Is it protected by anything? Are walls 2x4? Code is R20, so if you want to get near that for efficiency youll have to spray foam closed cell. If 2x6: batts and a sealed vapor barrier since you are heating cooling and habitatating to some degree. Id do a heat pump mini split and if it gets too cold during our -26 week or two every winter supplement with an electric space heater. But if that cuts your solar independence too much then wood stove and add some windows to open in the summer? Oh great. Code nazis. Most everywhere (or literally everywhere that i know of), outbuildings dont have building codes. R3 insulation, or R8700. Whatever you are able to do. But still, spray foam, especially closed cell, probably isnt the best product for that building. |
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Quoted: Oh great. Code nazis. Most everywhere (or literally everywhere that i know of), outbuildings dont have building codes. R3 insulation, or R8700. Whatever you are able to do. But still, spray foam, especially closed cell, probably isnt the best product for that building. Codes are still a good point of reference to use for your area to show what you would need if you expect comfort levels of a house. Especially when the OP is trying to be efficient . |
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Quoted: Codes are still a good point of reference to use for your area to show what you would need if you expect comfort levels of a house. Especially when the OP is trying to be efficient . I agree with this 100 percent. A few codes are BS (here anyway--I expect everywhere). But most are there for a good reason. Helpful to know them, and the why of them. |
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I have a 12 x 32 shed and a 12 x 16 addition on the back. Just used pink fiberglass wall insulation. I covered the interior walls with OSB boards. It just a hunting camp so no need for fancy. I use 2 (5K btu) window ac units here in Va. and it keeps it cool. In winter I have a wood stove and a propane wall heater. The wall heater is set on 2 of 10 setting and keeps us a toasted 80 degrees inside. My woodstove will run you out of the shed. |
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Quoted: I have a 12 x 32 shed and a 12 x 16 addition on the back. Just used pink fiberglass wall insulation. I covered the interior walls with OSB boards. It just a hunting camp so no need for fancy. I use 2 (5K btu) window ac units here in Va. and it keeps it cool. In winter I have a wood stove and a propane wall heater. The wall heater is set on 2 of 10 setting and keeps us a toasted 80 degrees inside. My woodstove will run you out of the shed. Do you have a big propane tank outside? Or do you feed it with small tanks? |
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On our ranch here we have 4 Mitsubishi mini-splits here for different buildings and uses. Range from one to 2.5 tons. Oldest was installed in 2015. Absolutely no issues with any of them. Need to clean (wash out) the screens/filters from time to time. Super quiet and efficient. Highly recommend them. One thing that you might consider is installing a dedicated surge protector at the unit that is suitable for outdoor installation. We put them on all of our units (including a high end Lenox 5 ton heat pump at the house). Why? We have blown two invertor boards on the Lenox in the last couple of years. Not from direct lightening strikes but rather surges through the coop power system during storms. Our HVAC guy is recommending these surge protection units for them as they have had blown mini-splits from similar power surges. We recently installed RectorSeal RH50 units; they are about $60-80/unit; so far so good. The problem was the heat pump blew the circuit boards despite the fact that we have a whole house Siemens surge protector; unfortunately it never tripped. The mini-splits made it through the surges without an issue but we have put the local surge protection on each unit anyway. Finally, I understand the infatuation with closed cell foam insulation due to its ease of installation and high R value. However I have elected to NOT use spray foam in any walls, etc. that interface directly with living spaces. My background is a process design chemical engineer and have been in the oil and gas/petrochemical industry for over 40 years.. I find it humorous that 10-15 years ago the public was all up in arms about off gases coming from foam cushions and mattresses (granted they were polyurethane based) but its ok to create a tight thermos bottle of a structure with foam all around it. On our new house I elected to use fiberglass bats in the ceiling (the attic is not part of the envelope of the house regarding HVAC) and blown/sprayed in cellulose in the 2x6 walls. The house has many additional features in the construction to make it extremely tight. My personal decision is that I did not want to spend long hours in an environment that was subject to the off gases from the foam, even if it was properly applied and cured. I realize that this is not a popular choice and many will blow this idea off, but you might check into some of the municipalities, states, organizations, etc. that are starting to ban it or limit its use. I still remember the great move to aluminum wiring about 30-40 years ago; I wonder how that turned out. Anyway, the current foams are generally not the polyurethane foams of years past but generally are isocyanate based. They are considered 'toxic' when applied but following curing (and assuming the foam was properly mixed) the danger is supposedly gone. Except for any dust that comes from it over time. And assuming the components that are mixed to ensure proper hardening were mixed in the correct ratios. Its just my opinion, but I believe that if proper construction is done and a 'tight' design is achieved there are plenty of more benign insulation products that can be used. Look into passivhaus standards and techniques for example. Even if you get a shell prebuilt you can ensure that there are not air leaks at transition points (roof to walls; walls to foundation; top and bottom of stud walls where penetrations occur for wiring, etc.). This is just one persons opinion (mine) so you can take it for what is worth. |
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Not that anyone asked..... Mini split brands can stir the pot like just like a "who makes the best truck" thread. In the end you can have issue with any of them. Put 30+ Mitsubishi units in a building about 10 years ago and all but 2 are still going strong. Almost all of them immediately needed indoor fan motors due to MFG defect. Mfg gave us the parts and said your on your own to install. Put in a couple inverter boards. maybe a compressor or two. Parts are available but expensive. newer installs (well over 100) get no brand loyalty. Whatever is cheap TotalComfort, Gree, Pioneer..... They all seem to work equally as well. Pioneer parts seem to mostly be available and cheap but we really haven't needed any. The few that fail over the years its generally easier and cheaper to just swap out the entire thing. Off Grid? Did you know you can easily find 110V or 220V units 9,000 and 12,000 BTU? The colder it gets the less heat they make The Higher the SEER (efficiency) the colder they can make heat 20 seer gets you about -13F we once measured a Pioneer 9K btu 115V unit and it consumed about 500-600 Watts. Not too bad if your on solar |
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Quoted: Rockwool. I will never use fiberglass again. I'm thinking this or hard foam. I'm having a hard time finding someone that will do the spray foam job in my area. Is there anything better than rock wool and just under spray foam? this will probably DIY. I should have it here delivered in a week or so and then I can start planning it out better. still looking at non 220 mini splits |
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Quoted: I'm thinking this or hard foam. I'm having a hard time finding someone that will do the spray foam job in my area. Is there anything better than rock wool and just under spray foam? this will probably DIY. I should have it here delivered in a week or so and then I can start planning it out better. still looking at non 220 mini splits If I had my best choice, I would do Rockwool (and 5/8 drywall) with the DIY spray foam kits for wall penetrations. I actually think this foam around light switch boxes and pipes (penetrations) is EXTREMELY important to a good envelope. JLC thinks so too, if that matters. The insulation you get from just sealing those small openings and thin spots makes an enormous difference. |
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Quoted: @Handydave Closed cell foam and a mini-split is my knee jerk answer but if it needs to be a DIY I’ll have to noodle on it. In my opinion Next best bet would be going back to what we called an air infiltration package. Fill all holes with caulk where wires run through top and bottom plates as well as foaming / caulking plate to ceiling & floor connections. Essentially try to get air infiltration down to zero. Love expansion foam around doors/ windows. Caulk electrical boxes to seal any holes where wires go through or unremoved knockouts. Then use the rockwool ( make sure to cut it around outlets and not just compress it ) After that I would consider 1/2 “ of foam caulked around the perimeter , electrical boxes, etc and taped at joints as another air seal layer. Then 1/2 “ drywall. High efficiency mini split heat pump with some type of hyper heat and a wood stove for ambiance or when it gets really cold. ETA. When I posed this I read the first few posts. I went back and read through the entire thread. It would have saved me a lot of time just to agree with ColtRifles post. I’m in Atlanta so I’m not familiar with the weather. Someone mentioned closed cell may not be a good idea due to moisture and lack of vapor barrier on the exterior. If so open cell may be a better option if you go the spray foam route. |
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I have been happy with mini splits. I originally just switched to them only because they were quieter than my window units. @Fastowl Where do you install the mini split surge protectors? At the shut off? I have 6 mini splits installed up at my farm for me and my inlaws. Thank you. |
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OP I don't live where it gets really cold, a few days freezing, but it gets hot as hell here and I put in a 110v mini split 9000 btu in my wifes mini house, it's a Pioneer unit, and cools it off real nice, they do make a 12,000 btu 110 unit too. Here are a few pics, I went with standard insulation, but spray foam is a lot better, house is closed cell foam and its excellent. I did my own electric, drywall and painting, turned out pretty good. Attached File Attached File Attached File Attached File Attached File Attached File |
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It hardy fit down the driveway! Attached File 1/4 mile later! Attached File |
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Quoted: OK so looks like spray foam and a mini split! It sounds unanimous! What is the mini split to get? I know nothing of them. ETA; I have a Mits in my guestroom over my garage also another unit in a small office in the garage both run off one condenser.They run 24/7/365. Very efficient and quiet, but pricey. Daikin cost a little less and I know people that are happy with them too. I'll be adding one in my shop in the next few months that won't run everyday. I'll get the cheapest one I can find for there. |
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Quoted: OK so looks like spray foam and a mini split! It sounds unanimous! What is the mini split to get? I know nothing of them. Mitsubishi, Daiken or Fujitsu Get the lowest temp option, given your location. Quiet, super efficient. I would get a 1T unit for your application. Supplement with a small wood stove if you like. |
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Quoted: If it's not built yet, I'd make sure there there is a vapor barrier (Tyvek) between the OSB and siding. I see you are in WI, it would be nice if you could spray under the floor too ETA; I have a Mits in my guestroom over my garage also another unit in a small office in the garage both run off one condenser.They run 24/7/365. Very efficient and quiet, but pricey. Daikin cost a little less and I know people that are happy with them too. I'll be adding one in my shop in the next few months that won't run everyday. I'll get the cheapest one I can find for there. It has some kind of coated wood siding (all one piece) and does have spray foam under it |