Shop build and heating in 2024

[westcliffe01]

FYI Home Depot has 2" R-Tech foil faced insulation, rated for under slab use. For my 40'x64' slab it says I will need 88 units for $1851. The Owens Corning Foamular 250 is more expensive at $4704. Their price has gone way up for sure.

 

[Too many Kubotas]

Floor heat is absolutely wonderful, I think.

Like westcliffe01 I thankfully don't need A/C. But I do have two 14' tall doors, the other three are 12 footers.

Already screwed up once (my garage in SoCal) and thought "I'll never need more height than that". Well, I did.

 

[miscjames]

That's a nice sized door.

What are the 12"x12" window frame outs with fans going to do?

How are you going to insulate the building?

My garage is about the same size as the shop you are building. So far it's just framed with a metal roof and house wrap on the exterior. My plan is to insulate the walls with R13 fiberglass, and then install metal siding for the ceiling, and blow in R60 Attic Cat insulation. I went with insulated panel doors because of the insulation. I've had Roll Up doors, but they leak too much air. I did the same thing for my parents garage and I've been amazed at how nice it is in there on the hottest or coldest days.

If I need to, I'll use a space heater to heat the area that I'm working, but for now, I'm not planning on doing anything else.

What are the 12"x12" window frame outs with fans going to do?
Pull the heat and exhaust off the top of the roof and I plan on running a dehumidifier as well to cut down on moisture and the fans will help that process.

How are you going to insulate the building?
Probably the 10psi foam board with foil face

 

[miscjames]

I’m in South Carolina.. not a huge need for heat, but when u need it, U NEED IT..
I work on a bench 99.9% of the time.. so no real need to heat the whole thing..

I have an electric space heater down low for my feet and legs..
A propane DUAL HEAD heater w a pedestal fan behind it, on low, to blow the hot air where I need it..instead of going straight up..
And a round kerosene heater, not the torpedo style, with a pedestal fan behind it..
The kerosene heater will warm the whole building but down here it’s 6.00 a gallon, so it’s a bit pricey to run..
It’ll run 8 hours on a full tank easy..
BUT HEY, it beats being cold..
Propane is much much cheaper to run and a small “grill tank” will last for days..

In Tenn u get cold and snow, so u might want something more permanent..??
Northern Tool sells the ones that bolt to the ceiling and are hard wired to the electrical panel..
Or u could go on FB market place and find a business that does it for a living that has a bunch of “take out” units.. with BOTH HEAT AND AIR..(cheap) but it’ll be depending on your electric box..
Good luck

In Tenn u get cold and snow, so u might want something more permanent..??

My primary goal is to keep the shop above freezing. Then a nice to work in secondary.

 

[miscjames]

I'm still in the planning stages for a new workshop here. I'm debating about under floor insulation and in slab PEX. I will probably go that way because I expect the shop to outlive me, and perhaps plans will change. Do it right the first time.

I want some brick in it. It will slow me down a lot, but that's what I'd like.

As far as roof insulation, I was originally interested in the fire resistance of rock wool. But I'm now learning more and more about closed cell spray foam that has excellent vapor barrier properties, and can also be reasonably fire resistant, especially when protected from oxygen exposure.

I think the spray foam can be applied directly to metal and will prevent condensation from forming at all in the back side of the metal.

I'm currently planning on wood heat. I have a fair amount of dead wood here every year, and think I can probably get a permit from the forest service to get wood out of clear cuts and slash piles.

I'm debating about under floor insulation and in slab PEX.
Surprisingly the pex is not that $ you can get a 1200’ roll of 1/2 oxegen barrier off amazon for like 400$ its that underslab insulation that is $$$

think the spray foam can be applied directly to metal - most metal building manufacturers will void their warranty if you use spray foam. At least is what i have saw so far.

 

[miscjames]

A few questions. Heated all the time or just kept above freezing and heated when working? Natural gas available? Electric supply?

Cheapest is probably gas furnace. Mini-splits may be a DIY option for you. For insulation, will you have a ceiling? That helps a lot on heating and makes a lot of insulation economical.

A few questions. Heated all the time or just kept above freezing and heated when working?
Yes this would be ideal

Natural gas available? No

Electric supply? Yes i plan on splitting off the house.

No ceiling

 

[westcliffe01]

My property is off grid, so the only electric I will have is solar PV and I have a diesel generator which I will be recovering heat off the coolant and exhaust to get the most $ per gal of fuel consumed. So having an insulated storage vessel for the hot water will help with the radiant heat. I have not yet decided on the primary heat source yet. I dont think I am going to do an outdoor boiler. Despite the amount of National forest and BLM land I still dont know how it works getting beetle kill wood off the slopes. I know they have a lot of rules banning motorized vehicles and power tools like gas powered chain saws, so I am going to have to see how firewood is brought off the mountain before I make any commitment to heating with wood. Its mostly softwood too, so thats another hurdle. Lots of volatile resin and very little in coals.

During construction I have 2 different passive vaporizing diesel heaters from the military, they dont need any power source or electricity. Fuel is gravity fed via an elevated jerry can. The small one is 9-12k btu. The larger unit will produce 20-60k btu with the same operating principle. Both are modern with an efficiency of about 72%. Obviously some sort of water heater would be the primary heat source. For now I am leaning towards a Rinnai Tankless water heater, the RU 130i which is a high efficiency tankless heater with a built in circulation pump. It only draws 38W when running and 1.3W in standby. It is also rated for altitude to over 10kft so my 9000ft is covered. The shop will have 2x6 walls with rockwool insulation and R60 over the attic and only 1 large door which will have 3" of foam insulation and the means to be latched against its jam reducing air leakage. I will be making the door myself and its balance system. The biggest electrical consumer will be the radiant system circulation pumps and I will get ones with DC motors so that they can run directly off battery power thus avoiding inverter losses. Once operational the radiant heat system will probably have its own dedicated 48V lithium battery system and solar panels and charge controller because the heating system is probably going to run most of the year. The generator will be on an auto start system should any of the batteries reach a predetermined voltage point.

Hunter arctic heater 9-12k btu

95-96% efficient tankless hot water heater.

 

[EddieWalker]

What are the 12"x12" window frame outs with fans going to do?
Pull the heat and exhaust off the top of the roof and I plan on running a dehumidifier as well to cut down on moisture and the fans will help that process.

How are you going to insulate the building?
Probably the 10psi foam board with foil face

I've worked in a lot of attics, and some of them have added fans to push the heat out of the attic. They paid a lot of money for those fans because they thought their attic space would be cooler, and that would it easier to keep the house cooler and save them money running their AC units. It doesn't work. It moves air, and air flow dries out an attic from condensation that's formed in the mornings from humidity, but just moving air around in a very hot space as zero impact on temperatures.

In your case, I think the same thing will happen, or it might be worse because you are trying to condition a space, but also dealing with 12"x12" openings that will allow heat to enter the building in Summer and leave the building in Winter. The biggest enemy in keeping the temperature of a room where you want it is air coming in and out of the building. The more airtight the building, the easier it is to keep the temperature where you want it. Windows and doors make this harder. Extra windows make it even more challenging.

Then there is the lack of R-Value for every window and door. R13 Walls with 2x4 framing, or R19 with 2x6 framing is easy to maintain with good ceiling insulation of R40 to R60, but every window is going to lower your R-Value because they are in the R2 to R3 range. Doors can be better, or worse, but not by much either way.

The better your insulation, and the better you control the air flow, the easier it is to heat or cool a space.

 

[KennyG]

Not sure why ventilating an attic doesn't work. When the sun heats a roof (especially a dark colored one) the attic gets much hotter than the outside air. Ventilation will bring it back down to near outside air temperatures. In one house I had a garage (no ceiling, no roof vents) that would get very warm in the summer. I added a non-powered, wind powered type of ventilator and soffit vents and it didn't get hot anymore. In the winter I would block the ventilator to keep it from getting so cold.

 

[Larry Caldwell]

A few questions. Heated all the time or just kept above freezing and heated when working?
Yes this would be ideal

Natural gas available? No

Electric supply? Yes i plan on splitting off the house.

No ceiling

I dropped a 400 amp service in the yard and split 200 to the house and 200 to the shop. The single meter let me dodge the charge for a separate service.