In Slab Radiant Heat

[JerrodGlover]

I put in the same in floor radiant in my new barn 2 years ago and would do it again in a second. I installed it 12" on center and just boxed out where the lift will go in the future. If I was to do it again I would up my insulation. I have 2" under the floor and 2" along the walls down 24". I would double all of that next time. The insulation is cheap compared to the cost of heating. I found the program LoopCad for doing the layout to be helpful. If figures out where you can make turns and keep the loops even. Then snap some lines on the floor and start stapling.

[Meyers Farms]

Originally Posted by Signature600

Should be fine. I think my shops are all 5/8" tubing, same run length and spacing. One slab is insulated , one is not. You can feel a difference in the heat in each building.

Sounds like you'll have it set up right all around.

What is your heat source?
Chris

Thanks for the info. I'm up in the air on heat source right now. It will be wood fired or gas fired. I have easy access to seasoned split firewood and heat my current house with wood. If I go that route I will heat the new shop and new house with one wood boiler. The other option is to heat the shop with a gas fired boiler and separate HVAC for the house.

Originally Posted by JerrodGlover

I put in the same in floor radiant in my new barn 2 years ago and would do it again in a second. I installed it 12" on center and just boxed out where the lift will go in the future. If I was to do it again I would up my insulation. I have 2" under the floor and 2" along the walls down 24". I would double all of that next time. The insulation is cheap compared to the cost of heating. I found the program LoopCad for doing the layout to be helpful. If figures out where you can make turns and keep the loops even. Then snap some lines on the floor and start stapling.

I'll look into LoopCad, sounds like it will be helpful. Is your slab 6" thick? And you attached the tubing directly to the insulation? What did you use for stapling the tubing to the insulation?

[JerrodGlover]

I have a 4” slab. Once it’s warm that is all that is important. Think of the slab as a big heat sink. There are staples to use made for attaching the tube to insulation. I got them at Menards.

I keep my barn at about 55 all winter. With my feet warm from the floor I work in a long sleeve t-shirt. Winter up here is to long and cold to not have good heat.

[Meyers Farms]

Originally Posted by JerrodGlover

I have a 4” slab. Once it’s warm that is all that is important. Think of the slab as a big heat sink. There are staples to use made for attaching the tube to insulation. I got them at Menards.

I keep my barn at about 55 all winter. With my feet warm from the floor I work in a long sleeve t-shirt. Winter up here is to long and cold to not have good heat.

I've never worked in a shop with a heated floor, although I'm looking forward to it! From what I've read and people I've talked to they say get it hot in the fall and don't mess with the thermostat until you're ready to turn it off. This obviously makes sense because of the heat sink in the concrete. It takes awhile to change the temperature of the slab. I've seen the staples at Menards and in fact a lot of the supplies for this building have come from there. Did you buy the stapler to install them? For $250 I was curious if it is worth it?
Also, do you have a temperature probe in the slab itself for the thermostat?

[Nootch]

I would expect to put a thermostat probe on the outbound line from the slab back into the heater. once the slab is at temperature, it will be a matter of finding what "feels right" and setting the temp there. Depending on the zones and layout you could get a fairly accurate reading of slab temperature from the water temp leaving the slab. As the slab cools off, it will cycle the heater on and maintain a balance point

[Signature600]

Originally Posted by Meyers Farms

I've never worked in a shop with a heated floor, although I'm looking forward to it! From what I've read and people I've talked to they say get it hot in the fall and don't mess with the thermostat until you're ready to turn it off. This obviously makes sense because of the heat sink in the concrete. It takes awhile to change the temperature of the slab. I've seen the staples at Menards and in fact a lot of the supplies for this building have come from there. Did you buy the stapler to install them? For $250 I was curious if it is worth it?
Also, do you have a temperature probe in the slab itself for the thermostat?

I started our boiler about the second week of October when it started getting into the 40's. You don't want to heat it up until its getting cool unless you can ventilate the shop well...if it's 70* and the floor is already hot, it's HOT in the shop

Originally Posted by Nootch

I would expect to put a thermostat probe on the outbound line from the slab back into the heater. once the slab is at temperature, it will be a matter of finding what "feels right" and setting the temp there. Depending on the zones and layout you could get a fairly accurate reading of slab temperature from the water temp leaving the slab. As the slab cools off, it will cycle the heater on and maintain a balance point

We regulate the air temp with a regular old thermostat, but it does have a sensor for the slap temp, and settings for a maximum floor temp so it can try to help regulate it. We keep the air about 65* which takes about a 71-73* slab temp in the big shop...100' x 120' x 24' building. I only got the slab temp thermostat last year because I was tire of the old thermostat...before that, he just an old manual slider which was too easy for my employees to play with...the digital, you have to unlock first.

It's not rocket science, you just set a thermostat and forget it after you get it adjusted. you DO NOT want to play with it, just get comfortable, and let it do its thing. It takes a long time to warm up or cool down, so messing with the thermostat just wastes fuel and money.

Chris

[bna5017]

Originally Posted by Meyers Farms

Thanks for the info. I'm up in the air on heat source right now. It will be wood fired or gas fired. I have easy access to seasoned split firewood and heat my current house with wood. If I go that route I will heat the new shop and new house with one wood boiler. The other option is to heat the shop with a gas fired boiler and separate HVAC for the house.




I'll look into LoopCad, sounds like it will be helpful. Is your slab 6" thick? And you attached the tubing directly to the insulation? What did you use for stapling the tubing to the insulation?

As far as LoopCAD is concerned, almost anywhere that you are going to buy your radiant tubing and manifolds from has the ability to do a layout for you with equal length runs. I installed radiant heating in my house when we built it, both in the basement and under the sub-floor and am currently building a shop with it in the floor as well. All of the suppliers I have worked with gave me a layout for no additional cost.

[Meyers Farms]

Originally Posted by Signature600

We regulate the air temp with a regular old thermostat, but it does have a sensor for the slap temp, and settings for a maximum floor temp so it can try to help regulate it. We keep the air about 65* which takes about a 71-73* slab temp in the big shop...100' x 120' x 24' building. I only got the slab temp thermostat last year because I was tire of the old thermostat...before that, he just an old manual slider which was too easy for my employees to play with
Chris

I was afraid with this style, I might have the door open for a few minutes moving stuff in or out and the cold air would kick the boiler on, just to have it shut off after the doors were shut? Sounds like this may not be a problem.

Originally Posted by bna5017

As far as LoopCAD is concerned, almost anywhere that you are going to buy your radiant tubing and manifolds from has the ability to do a layout for you with equal length runs. I installed radiant heating in my house when we built it, both in the basement and under the sub-floor and am currently building a shop with it in the floor as well. All of the suppliers I have worked with gave me a layout for no additional cost.

I looked on their website, LoopCad has a free trial which I have not downloaded yet. I’m looking at a couple places right now to buy tubing and manifolds online. Sounds like a call to them is needed.

[Meyers Farms]

Originally Posted by Nootch

I would expect to put a thermostat probe on the outbound line from the slab back into the heater. once the slab is at temperature, it will be a matter of finding what "feels right" and setting the temp there. Depending on the zones and layout you could get a fairly accurate reading of slab temperature from the water temp leaving the slab. As the slab cools off, it will cycle the heater on and maintain a balance point

This sounds even better than an actual probe in the concrete. I will have to do some more research on this. I am going to have one zone and one temperature. I won’t have any separate rooms in this shop.

[Nootch]

Originally Posted by Meyers Farms

This sounds even better than an actual probe in the concrete. I will have to do some more research on this. I am going to have one zone and one temperature. I won’t have any separate rooms in this shop.

If you wanted to overthink and plan way too much. you can look at things on a +/- scale of adding and removing heat. the hot water in adds more heat at the beginning than the end. at some point it all equals out to maintain a level. If you have an area that soaks up more natural heat like a garage door with lower R value than the 3 other walls, you may want to have the first parts of the loops there and then to the rest of the slab.

garage door
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[Meyers Farms]

I was planning on running lines across the front (two garage doors) first to try to add the most heat out front where I expect the most heat to be lost. Thanks for all of the tips.

[thatguy69]

I'm thinking of running my pex out past my garage doors 6 or 8 inches to prevent snow and ice buildup. Wondering if that is really needed though. or if we could just run it flush with the door, I guess I'm not sure how far out it'll radiate past the pex itself.

[zstroken]

Originally Posted by thatguy69

I'm thinking of running my pex out past my garage doors 6 or 8 inches to prevent snow and ice buildup. Wondering if that is really needed though. or if we could just run it flush with the door, I guess I'm not sure how far out it'll radiate past the pex itself.

That is common, make it it's own zone though so you can shut if off when not needed. I would probably even look into an in concrete temperature sensor so you can adjust it to maintain concrete temp just high enough to keep the ice from forming.

[Signature600]

Our ice melt is 3' out in our aprons to melt where the doors open and close.

If you can, run your ice melt on a separate loop that you can turn on and off as needed, because it loses a TON of heat through those loops and takes hot water away from the rest of the floor.

Now, mine may be extreme, because that zone is 120' long x 3' wide, but the total volume of water in my system is much bigger than most, so the heat loss should me buffered by that. When I turn on the ice melt, the boiler doesn't shut off. Lots of fuel.

Chris

[thatguy69]

Originally Posted by zstroken

That is common, make it it's own zone though so you can shut if off when not needed. I would probably even look into an in concrete temperature sensor so you can adjust it to maintain concrete temp just high enough to keep the ice from forming.

I like this idea

[Meyers Farms]

Downloaded the free trial version of LoopCad tonight. Free trial lasts for 30 days. I played around with it for about 15 minutes tonight and it is going to work great. I will create a layout and edit it to my liking then order material. The goal is to get the tubing layer by thanksgiving and concrete poured shortly after.

[Meyers Farms]

Just to update this thread. I got the tubing installed and the floor poured before Christmas. The building has been all sealed up since I got the floor done, which was just in time for the winter rain (maybe we will get some snow this year?). Now to work on the interior.

[thatguy69]

I'm just behind you, getting ready to level the floor up with gravel and then lay my insulation and pex down. Already have the perimeter insulation done. Post pics if you don't mind, and where did you end up getting your supplies?

[Meyers Farms]

I got all of my supplies from pexuniverse.com. They had everything I needed and shipped very fast. I shopped around and they were the most inexpensive, I would absolutely use them again. I ended up attaching the pex to the insulation and it went very smoothly. I made each loop solid with no splices and didn't have any leaks. The lines were under pressure during the pour and I didn't have any issues. I have some pics, I'll see if I can post them.

You may have said earlier, but what size floor are you pouring?

[thatguy69]

36x40. So you bought one of those fancy pex staplers? Also did you put rebar out mesh down? That's what I planned on securing mine too