Radiant in floor heat (concrete slab)

I am in the process of building a 60x100 red iron building. 25x100 lean to off one wall, I am less than $20/sqft. with concrete, building package, labor to erect building. Have not bought doors yet or wired it. The cost of a building like this goes up tremendously when a GC gets involved. As in probably doubles, its ridiculous.

@Stuntman Autoworks if you want to check it out sometime it aint but 4 miles from your work. Might give you some ideas about what you do or don't want in yours.
Sounds good I'll get up with you. I won't be getting a GC like you probably didn't and ill be doing all the plumbing, wiring, and probably erecting of the building along with doing all the finishing inside.
 
This would be another negative (in my book) for attempting any kind of radiant floor heat.
That is also another consideration for when I start getting more solid numbers on everything. It is also seeming that I won't go radiant because of machinery and lift placement in the future. What would be the next best system you would recommend?
 
Not going to disagree that cost goes up with a GC, most will charge 10-20% of total cost.

Cost also has a lot to do with the county your in as well. Concrete up here is probably 20 dollars a yard more. Also a building that size would require engineered drawings here $.

There are also usually size slots that they engineer to which if you go small on that slot the building cost more per sq ft than doing a bigger building in the same slot size.


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Engineered drawings showing it will hold up to wind and snow are required here also.
 
Not going to disagree that cost goes up with a GC, most will charge 10-20% of total cost.

Cost also has a lot to do with the county your in as well. Concrete up here is probably 20 dollars a yard more. Also a building that size would require engineered drawings here $.

There are also usually size slots that they engineer to which if you go small on that slot the building cost more per sq ft than doing a bigger building in the same slot size.


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My building has stamped drawings, $750 iirc, footer/pier/slab design was $800 for stamped plans/drawing. I aint just trying to prove you wrong, please don't think that, but let me give you an example. Local "metal building company" quoted me nearly 30% higher for the building package than what I could buy it for. They were almost 3 times the amount to erect it than what I contracted some guys to do it for. My point is there are reasons these guys have 2nd homes in the mountains or on the lake. I fully agree that concrete prices vary and all that, I am fortunate that I'm only 4.5 miles away from the plant but plants further away gave me similar prices.
 
What would be the next best system you would recommend?
Totally depends on your needs/wants/priorities.

What's MOST important to you?
Heat in winter?
ventilation?
Cooling?
Is GAS an option?

If Gas is available, and you're not concerned with Air conditioning the shop, then I would do gas fired radiant ceiling mounted heaters. Big Ass Fans, and a peak mounted sidewall exhaust fan with an interlocking intake damper on the lower portion of the opposite wall of the building to draw air across.
 
Totally depends on your needs/wants/priorities.

What's MOST important to you?
Heat in winter?
ventilation?
Cooling?
Is GAS an option?

If Gas is available, and you're not concerned with Air conditioning the shop, then I would do gas fired radiant ceiling mounted heaters. Big Ass Fans, and a peak mounted sidewall exhaust fan with an interlocking intake damper on the lower portion of the opposite wall of the building to draw air across.
For the shop
winter heat
Ventilation
Not concerned with cooling, it would be nice but I don't think I can justify the cost
 
Totally depends on your needs/wants/priorities.

What's MOST important to you?
Heat in winter?
ventilation?
Cooling?
Is GAS an option?

If Gas is available, and you're not concerned with Air conditioning the shop, then I would do gas fired radiant ceiling mounted heaters. Big Ass Fans, and a peak mounted sidewall exhaust fan with an interlocking intake damper on the lower portion of the opposite wall of the building to draw air across.
Only propane in my area, no natural gas
 
We have a 75x50, with attached 40x32, and additional open 40x32.

Not much insulation, it’s there and whatever was common for early 80s red iron building.

2-3” fiberglass with poly vapor barrier between tin and red iron.

It’s tall.

In the winter we use a propane blast heater and one of those propane infrared patio heaters. This is enough to take the chill off.

The coldest I have ever seen the slab was 42, it’s usually 48-55 in the winter. I don’t notice the slab being cold, I notice the chill in the air more.

2 hrs of running the heaters and the chill is out of the air, and the patio heater is enough to roll near where you are working.

I’m usually in bib overalls and a hoodie. Any warmer and it’s jeans and hoodie or long sleeve shirt.

My point to all that, in the spring and fall when the slab cools but the air is still humid, there is a ton of condensation on the slab. It’s ridiculous. That’s more of a nuisance that the cold.

The summer heat is practically unbearable no matter how many fans or ventilation and open doors.

This is why I got a 4ton gas pack to put on the 40x32 side with a shorter ceiling.

I use AC far more than heat with our climate.

It won’t get down to 70°, but it will get down to 78-80° from 94-96° but the big thing is pulling the humidity out where it’s comfortable to work, and my sweat actually evaporates.

Before that, it’s just non stop leaking sweat and the fans just circulate hot air.

Swamp coolers don’t do jack when the air is already full of moisture.

Just my .02.

If I were building new, I’d save and not do radiant floor, but would do a wood stove inside with a fan for circulation.

Plus a propane gas pack with air conditioning.

The productivity in the summer far outweighs the need for heat in the summer, for me.

Meaning, get the living area to 70° or whatever you want, and shoot to get the shop to 55/60° in winter, and 80 in the summer at floor level. Still insulate the living area from the shop, but let the living area be inside the envelope of the shop, so you have less temp differential from living spare to outdoors compared to a conventional house.

I’d consider spending the cost of the radiant floor system on extra/better insulation in the big building.

I’m no train driver, but I’d consider cost/energy use of using one big 12.5-15 ton unit mentioned above vs multiple 4-5 ton units.

I’m just not fluent in comparing the use/cost/efficiency of such.

Then mini splits or gas packs for the living area.

But I’m in an area with natural gas, and I love gas heat.
 
I’m no train driver
:lol:
It won’t get down to 70°, but it will get down to 78-80° from 94-96° but the big thing is pulling the humidity out where it’s comfortable to work, and my sweat actually evaporates.
Very much this. I'd take a cold shop over a stagnant, humid shop any day.
 
I would do gas fired radiant ceiling mounted heaters

If you're only concerned about heating specific work areas, a few radiant heaters would be all you need. The air temp could be fairly low, but if the radiant heater is pointed at you, you'll be warm. It's a different heat transfer mechanism (radiant vs convection) than a heated floor, but the effect on the space is similar. If you have a heated floor, the building can be drafty as shit. If your feet are warm, you're comfortable.

Also, from an engineering standpoint, keep in mind that these buildings are designed to the absolute bottom dollar. If you're planning on hanging *anything* from the walls or ceiling, you need to make sure it's accounted for in the shell design. If there's going to be insulation, ceiling, lights, ducts, fans, mechanical units, etc, it needs to be stated in the structural drawings. A lot of these buildings that fall down in the winter have likely been altered beyond their original designs in ways that overloaded the structure.
 
Also, from an engineering standpoint, keep in mind that these buildings are designed to the absolute bottom dollar. If you're planning on hanging *anything* from the walls or ceiling, you need to make sure it's accounted for in the shell design. If there's going to be insulation, ceiling, lights, ducts, fans, mechanical units, etc, it needs to be stated in the structural drawings. A lot of these buildings that fall down in the winter have likely been altered beyond their original designs in ways that overloaded the structure.
My sales guy asked me about that when I bought mine. Would I have anything on the roof? Would I have components hanging from the beams? It all matters.
 
I’ve thought about radiant floor for my imaginary shop. But I think I’d rather go forced air with geothermal for both heat and a/c
 
Lol! With the massive tax credit gone, it's not worth it for a home. For a shop, I don't think the math would add up even with the tax credit.
This and Granite 75 ft below mostly sandrock/shale take geo even out of consideration for me.
 
This and Granite 75 ft below mostly sandrock/shale take geo even out of consideration for me.
I have also read horror stories of improperly sized systems that wind up with higher than anticipated energy bill because of oversized/continuous running pumps etc.

Like @jeepinmatt I did foam insulation and my highest bill over the past year was August @ $170. That was during "quarantine" with my wife and kids home all day everyday. My wifes idea of energy conservation is actually optimum comfort... IE, every light and ceiling fan on and the AC set at 70. Nevermind the days on end that she and the boys forgot about, and left the playroom mini split running on full blast...
 
I fired up the radiant heat for the 1st time last Tuesday about 6pm. here is the energy used so far.
the shop is 28'x40' with 14' side walls. insulated on the walls and ceiling.
the tank-less electric heater is 10kw.
the thermostat on the wall it was set to 60 initially but, turned it down to 57. i don't have a probe in the floor.
after about 15 minutes in the shop i'm down to a short sleeve shirt and comfortable.
my feet love the warm floor.
 

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I fired up the radiant heat for the 1st time last Tuesday about 6pm. here is the energy used so far.
the shop is 28'x40' with 14' side walls. insulated on the walls and ceiling.
the tank-less electric heater is 10kw.
the thermostat on the wall it was set to 60 initially but, turned it down to 57. i don't have a probe in the floor.
after about 15 minutes in the shop i'm down to a short sleeve shirt and comfortable.
my feet love the warm floor.
Awesome, thanks for the feedback. I'm not sure what I will do but the layout of equipment, lifts and anything I may get in the future has me worried with mounting things in the floor. I'm worried that as I add equipment I may decide to change the layout of everything so no set in stone plans of layout for everything.
I am also currently thinking of splitting the shop and living area for noise, dust and odor reasons but not real sure yet.
 
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