radiant in floor heat in pole barn?

I have been planning to build a pole barn approximately 24x 36 and was wanting to put tubing in the floor for heating down the road. However I have been told that in order to do this the right way I would either need to put in frost footings and insulate in between the footing wall and the slab, or bury 2" foam vertical in place of the footing wall to keep the frost from coming under the slab. I understand that I would need to put foam under the slab to insulate it, and foam around the perimeter for insulation also. I guess I don't understand the frost issue 100%. Has anyone done this in a colder (North NE) area and how did you do it and how did it work? thanks for any ideas and help in advance.

That sounds like how it is done around here- talk to some local contractors for info as well. Our basement floor heat does not have vertical insulation, but does have 2 inch styro over the sand. Our threshing club building has the vertical insulation on the perimeter.

I have a close friend who owns an HVAC company... he specializes in radiant. I've spoken with him about this subject & according to him, you can install a radiant system with underslab foam insulation & the footing insulation, without the footing insulation, or with no insulation at all. In the latter case, he mentions that when you start up the heat for the season, it will take a while longer to warm the floor but, once warm, the ground under the floor will serve as additional thermal mass and will add to the overall effect. He said that the heat will go down about two feet or so, and that's it, so, no real problem and, as I mentioned, the soil under the slab just turns into several more tons of thermal mass. As far as heat loss around the perimeter, it's true, you will lose a bit there... might need some additional tubing to minimize "cold spots" in the floor near the perimeter walls. If you're worried that frost will be a problem that may affect your posts, one thing you could do is pour a slab completely around the perimeter of the building, width of slab will be equal to the depth of frost you experience in your location. Reason: soil under this slab will not freeze & the frost will move under the slab at an approximate 45 degree angle. So, if your frost line is 36", a 3' wide slab around the building will allow the frost to penatrate 36" deep by the time it gets to the actual building perimeter. This would also moderate the soil temperature at the perimeter of the building and further minimize heat loss at the edges of the slab. Keeps weeds & grass (fire hazard) away from the building as well! HTH ...D

It's not the rocket science some folks make it out to be,but the more you insulate the less energy you use. Floor heating is a lot more common over here. I'll dig up some info/pics for you tomorrow. Easier if I email it to you though. Just shoot me an email so I can reply.

Dave

Why you planning on getting kicked out of the house. (giggle)
Walt

As cold as some of you folks get, running 40 degree water through it would be like a heatwave :roll:

I did it in Central Wi. 12 yrs ago according to
plans I got from North Dakota St. University. Put vertical Polystyrene around the perimeter, Polystyrene and sand under the floor, reinforcing rod in the concrete one foot on centers. The tubing was plastic tie wrapped to the reinforcing one foot from the wall on the first loop, then 2 feet on center round and round to the middle then back to the corner where the water heater and pump and other stuff was. Worked great, you have to use polystyrene insulation 2 inches thick. Strofoam will deteriorate. I called Dow Chemical in NJ to learn this.talked to a very helpful chemist.
My present 2 car garage in NY has Bubble wrap laid all over the origional garage floor and four inches of concrete poured over that. 1/2" pex tied to wire reinforcing mesh and hooked to a 30 gallon water heater, works real well also. Both buildings are very well insulated.

We built a 40x40 workshop last year, with floor heat, we put 2 inch Styrofoam (below ground rated) under the concrete, we used a 2x8 as the form for the concrete (pole barn went up first) and then used spray foam in the walls which went down to the Styrofoam under the concrete around the edge of the building... I"m in Manitoba Canada, it gets a little cool here once in a while... the frost problem comes up when the concrete is in direct contact with the ground or and uninsulated wall or other structure... it allows heat to escape faster than it can be replaced... not good for the heating bill

Lot's of info here.
http://www.radiantdesigninstitute.com/page2.html

Well Walt I don't have to plan to get kicked out it just kinda happens, must be some sort of gift or something. lol. Next question is will the frost heave the poles separately from the slab, or the slab and not the poles more likely?

I can't figure out how to email you heres mine. [email protected] thanks

Go to "Heating Help.com" and get the book from Dan Holohan about radient heating. They also have a "wall" that heating pros hang around to answer these kind of questions.

HHHMMM, I've been in the concrete/excavating business all my adult years and frost gets the deepest under pavement. The frost under the middle of the road is always deeper than at the edges, sometimes by more than a foot.
I've got a 62' X 45' pole barn with in floor heat and a boiler. 2" insulation undeer the slab, 6" in the walls and one foot of blown in in the ceiling. This is North East Illinois.
Costs about half to keep it at around 58 deg. that it costs to heat my house.

When I bought my PEX I asked the dealer what was best and they wanted Foil Backed double bubble insulation. They claimed you would gain a lot of heat from the reflection back up. I did it their way but I have never hooked the pipe up.

(quoted from post at 15:30:05 03/06/10) I can't figure out how to email you heres mine. [email protected] thanks

Click to expand...

OK. If you can check the ND university website, Dave Sherburn described what we did to a T.... I'll see what I can dig up today. Keep in mind, I KNOW NOTHING ABOUT LOCAL CODES. So, code police, stay off my back :lol:

Dave

I'm at work and the pics on the website I was thinking about are not opening on my computer. Again, just as Dave Sherburn described. If it's just a barn or workshop, do you really need to heat the whole floor? What is your idea/s for the building (how warm do you want it)?
Just an idea, but if I had a 24x36 shop, I'd prepare the whole thing ready for the reinforcing. Form, add 2 inches of gravel, reinforce, and pour it 4ft in from the walls leaving a route to where you'd put your boiler (leaves you 16x28 open).

Then, put down 2 inch thick foam and 1 inch foam border, reinforce, and fasten your water (heater) tubing keeping it >6 inches from the edge and a foot apart. No since heating under a work bench or toolbox. In my house (100+ years old) part of the floor (warmest part without heating) was hard packed something (harder than dirt but not quite concrete) 3-4 inches of sand for insulation, and hardwood floor over it. Depending on how cold it gets in your area and prices, sand may be an option for you.

Good Luck,



Dave

That really isn't the way in-floor heat works in a slab in a northern climate - I'm in Minnesota - and I'd be real scared you would get poor results from that sort of mish-mash setup.

The idea is to heat up the slab of concrete, and let it heat things close to the floor, so you don't waste heating the air way up top. A person can feel real warm on a 55-60 degree floor; while you feel real cold in a building that is 65 but all the heat is up in the ceiling, with a cold floor.

Sand is a poor heat tranfer medium, so they don't recomemend that.

Leaving parts of the slab without heaters in it means you have cold spots, which messes up the heat flow & will create downdrafts and just generally mess it all up bad.

Might work in a warmer climate, but I don't see much that would work well in a cold climate?

You want even heat, you want good heat transfer, you want to keep the building cooler than normal but done right it will feel warmer than average, and you dwant it heated all winter long, no turning off for the week, turning on for the weekend.

it's a system, you want the whole chunk of floor to be your heat sink, you want the heat to lightly rise striaght up, and you don't want heat to bleed off to the outside of the building - out the sides of the slab or foundation. Isulation is critical there, not really so terrible important below - heat loss down will not be bad, but it is terrible off to the sides.

--->Paul