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Bobby Hatfield
01-27-2004, 6:26 PM
Anybody have experience with radiant floor heating in a new concrete floor ? Thinking of using it for heat in new shop, with 16' ceiling with the open attic, to heat the shop with stoves will cost more than the shop. Curious about zone heating, like heating the area with machines only on days when milling parts, then assembly when needed.

Glenn Clabo
01-27-2004, 6:43 PM
New shop? Did I miss the announcement moment?

Radiant floor heating is, IMHO, the best heat for a shop. I once worked in a building that had radiant heat and it was always comfortable. I liked the feeling of warmth coming up through my feet instead over my head.

Now...are you going to pad it in anyway...the old knees ya know? I don't know how that affects it.

Now what's with the new shop?

Dennis Peacock
01-27-2004, 6:54 PM
So what's this about a NEW SHOP?!?

Radiant floor heating is really neat and most of the warmth is near YOU and not up around the roof line. The concrete is a great heat sink and will release the heat more evenly than forced air heating. Sure wish I had radiant floor heating in my bathrooms in the house..!!!!

G.C. Wagner
01-27-2004, 6:54 PM
I've got it in mine. I don't have any separate zones since I don't have anything but one big (30x40) open space. I have a steel truss building with 10 foot walls so it's open to the roof peak which is about15 feet.

It stays very comfortable and best of all there isn't a blower to send dust everywhere. I think that I would do it again if I were to build another shop. The only thing that I would do diferent would be to insist on insulation under the slab and keep looking until I found a concrete contractor willing to do it that way.

In short, I love it.

Gerry

Chris Padilla
01-27-2004, 7:06 PM
...The only thing that I would do diferent would be to insist on insulation under the slab and keep looking until I found a concrete contractor willing to do it that way.

Gerry

Gerry,

Could you explain a bit what you mean by "insulation under the slab" and why you had difficulty having it done?

Thanks

Bobby Hatfield
01-27-2004, 7:17 PM
Gerry, come again on that insulation under the slab. I was wondering about something like that and also insulation around the edges between the footing and slab.

Bobby Hatfield
01-27-2004, 7:20 PM
Yeah, Glenn, when the rent goes up too much I think, I could use that to pay for my own building, I want a place to keep and work on the bus too. I think I will try some of Terry's horse stall mats for the ole knees and hip joints.

Bob Marino
01-27-2004, 7:21 PM
Bobby,

From what I understand, radiant floor heating is the most comfortable way to heat a shop.

Bob

G.C. Wagner
01-27-2004, 7:25 PM
Chris,
I don't remember the exact thickness but the people that sold me the system said that you should use foam insulation under the slab to keep from having to heat up the fill and earth under it. I'm sure that I probably use more LP gas because of not having it.

As to the reason I didn't get it done that way, the guy I hired had the reputation of being "the best" in the county and while he did the best finishing work I've ever seen, he was also living back in the dark ages. He wouldn't even think about it. Didn't believe in fiberglass strands in concrete and would send back the truck if it arrived with any evidence of fiberglass having been added to the last load the truck hauled. Non of this new-fangled stuff for him!

To be fair, the floor only has hairline cracks in it after 5 years.

Gerry

G.C. Wagner
01-27-2004, 7:38 PM
Bobby,
I bought the system from a company in Minnesota. Can't remember the name but if you're interested I'm sure I've still got the receipts and info on it. I think it would be a good idea to insulate around the outside also. Yesterday we had ice everywhere and it was melted away about a foot around the building where there is concrete. So you know that some of my heat is being wasted heating up the ground around the shop.

Bob Marino is right about it being comfortable. It is a very even heat without any cold areas.

I have some of Terry's horse stall mats also. I'm 66 and my joints and especially the knees sure do appreciate them.

Gerry

Joe Breid
01-27-2004, 8:20 PM
I have infloor heat in my basement shop. The main reason that I put this in was so that I could seal the shop from the rest of the house. It works great.

The heat source is a gas fired hot water heater.

There is one zone for the shop and two for the living area in the rest of the basement.

The installation included 2 inch foam board with the water pipes laid on top of the insulation and the concrete poured on top of this.
Because the concrete is a big heat sink there is a long lag period from when the thermostat calls for heat to when the floor warms up. I try to set the water temperature so the zones run more than half of the time.

I would put this in again in a heartbeat,

joe

Chris Padilla
01-27-2004, 8:38 PM
Joe/Gerry,

Excellent posts...thanks so much for the information. I am kicking around adding a basement to my existing home and putting in-floor heat is a fantastic idea. The insulation under the concrete also sounds like a good idea.

Bobby Hatfield
01-27-2004, 11:07 PM
I've got it in mine. I don't have any separate zones since I don't have anything but one big (30x40) open space. I have a steel truss building with 10 foot walls so it's open to the roof peak which is about15 feet.

Gerry

Gerry, how big is the boiler for your system ? I hope to build a 40'X80' with 14' center asile without pipes in it, it will need to support heavy vehicles, so I will divide each side into 2 zones each and arrange tools to zones in like kind operations, cutting/shaping, sanding/assembly, with finishing being done in center aisle, downdraft booth with permanant side walls and doors that close on each end for use.

Terry Quiram
01-28-2004, 7:13 AM
Bobby

My shop is 32x44 with radiant heat. I heat the building with a 50 gal water heater. Insulation blanket under the slab was supplied by a radiant contractor. I will get a name and phone number if you want. Insulate around the floor between the wall. A radiant contractor can "design" your layout so the runs are equal. I have 5, 150' runs. Tubing is attached with plastic cable ties every foot. I did that labor and saved a bunch. (Oh my aching back :D ). The contractor hooked up the mechinacals. Be glad to answer specific questions. I keep my thermostat set on 62 and it is a very comfortable temp to work in.

Terry

G.C. Wagner
01-28-2004, 9:22 AM
Bobby,

I've got a 110,000 BTU boiler but it's way more than I need although there's not much time between temperature changes in the floor. The people that designed the system said that 60,000 BTU would do it. This was sort of a desparation move since winter came on me and I had to grab something that would work. I tried a 60 gallon hot water heater at first but it was electric and wouldn't even come close when the weather really turned cold. It ran continously and just couldn't get the water hot enough before it circulated out in the floor. We don't have gas in this part of the county so I had to put in a 500 gallon LP tank for the boiler.

I've heard about a lot of people that have used hot water heaters but I'm sure they're gas. This might have worked for me if I had the insulation that I should have had. I keep things around 65 degrees and that's very comfortable.

I've got 4 sections with 300 feet of 1/2 inch tubing in each. I also did the labor tying it every foot so I can tell you Terry's right about the aching back. I also did all the mechanicals myself but I had really detailed instructions. Of course you do a lot of things yourself when you can't find anyone that understands what you're trying to do. Every time I tried to talk about it around here people got that "deer in the headlight look" so it was a little hard.

Sorry about the long winded post but if nothing else, remember this one word, INSULATE. Oh, did I mention INSULATE. Don't make the same costly mistakes I made.

Gerry

Paul Downes
01-28-2004, 7:41 PM
Bobby, My brother-in -law built a 36 X 80 pole barn for his logging truck. Mind you this is in western upper Michigan where they typically have 3 seasons of good hockey weather and 1 of rough sledding. It's Usual to have 300+ inches of snow per year. He uses an out-door wood fired stove (central boiler) and has radiant heat in the barn including the pit that runs down the middle. I've worked in my t-shirt in that barn when it was -10 to -20 outside. It stays around 75 in there.

I'm thinking about adding to my pole barn to expand the wood shop, and am also thinking about putting radiant heat in the new 12 x 32 section before I pour the floor. I know it is important to put enough insulation down under the slab. I would think the amount would depend on your local average temperatures. More insulation is always better. Incidentally, I'm looking into reject foam insulated panels for the addition walls. I have been told that they go for $1 per sq. ft. @ 4" or 6" thick & they have a high R-value. I figure that if the addition's radiant heat isn't enough to heat the whole shop, I will look around for an old radiator or two to supplement. Heck, maybe I'll turn it into a hill billy shop and just hook up a bunch of old auto radiators and run a fan over them :D

Ken Fitzgerald
01-28-2004, 8:05 PM
Bobby, I am in the process of designing a woodworking shop. There are a number of companies that have web sites that sell their products and will help you design your system for free. After a lot of research the best designs I've seen recommend 2" of insulation around the outer 4' perimeter of your slab, then 1" of insulation under the next 4' feet of your slab; leaving the middle uninsulated. In short the outer 8 feet around the perimeter of your slab is insulated and the center portion is uninsulated. Most heat is lost around the outer edges of the building. Insulating there will decrease heat loss and provide a quicker response to a change in thermostat setting. Leaving the center portion of the slab uninsulated will utilize the effect of thermal mass. In other words the building won't cool down as quickly because of the thermal mass. If you insulated the entire area, you wouldn't have any thermal mass effect except for the mass of the concrete. If you didn't insulate at all, it would use the thermal mass effect of about the top 2' of the earth under the floor and would take sometime to cool down. Like wise it would take longer to warm up. I hope to use radiant floor heating in my new shop, budget allowing.

Bobby Hatfield
01-28-2004, 9:15 PM
Bobby, I am in the process of designing a woodworking shop. There are a number of companies that have web sites that sell their products and will help you design your system for free. After a lot of research the best designs I've seen recommend 2" of insulation around the outer 4' perimeter of your slab, then 1" of insulation under the next 4' feet of your slab; leaving the middle uninsulated. In short the outer 8 feet around the perimeter of your slab is insulated and the center portion is uninsulated. Most heat is lost around the outer edges of the building. Insulating there will decrease heat loss and provide a quicker response to a change in thermostat setting. Leaving the center portion of the slab uninsulated will utilize the effect of thermal mass. In other words the building won't cool down as quickly because of the thermal mass. If you insulated the entire area, you wouldn't have any thermal mass effect except for the mass of the concrete. If you didn't insulate at all, it would use the thermal mass effect of about the top 2' of the earth under the floor and would take sometime to cool down. Like wise it would take longer to warm up. I hope to use radiant floor heating in my new shop, budget allowing.

Wow, Ken thanks, I have been searching on the net with google and info like this just isn't on there so far. I have to build up the spot where I am planning to put the shop, its a little low and water stands for a while after a rain, I thought I would build it up with 6" rip-rap crushed rock and cover that with SB2, but probably should dig down and remove all topsoil and backfill it to 12" above grade, and pack it before spreading the SB2 crushed rock on it, or maybe not even use the crushed rock. Since I plan to build up the rest of the lot before building a house there I want the shop high enough that the backfill will not create a water problem when it rains.

Bobby Hatfield
01-28-2004, 9:29 PM
Bobby, My brother-in -law built a 36 X 80 pole barn for his logging truck. Mind you this is in western upper Michigan where they typically have 3 seasons of good hockey weather and 1 of rough sledding. It's Usual to have 300+ inches of snow per year. He uses an out-door wood fired stove (central boiler) and has radiant heat in the barn including the pit that runs down the middle. I've worked in my t-shirt in that barn when it was -10 to -20 outside. It stays around 75 in there.

I'm thinking about adding to my pole barn to expand the wood shop, and am also thinking about putting radiant heat in the new 12 x 32 section before I pour the floor. I know it is important to put enough insulation down under the slab. I would think the amount would depend on your local average temperatures. More insulation is always better. Incidentally, I'm looking into reject foam insulated panels for the addition walls. I have been told that they go for $1 per sq. ft. @ 4" or 6" thick & they have a high R-value. I figure that if the addition's radiant heat isn't enough to heat the whole shop, I will look around for an old radiator or two to supplement. Heck, maybe I'll turn it into a hill billy shop and just hook up a bunch of old auto radiators and run a fan over them :D

Yeah Paul, I want a pit in the center isle of the shop to use for working under the trucks and Bluebird, if and when, I will check on the price of the pit when I get my estimate for the concrete work but will not heat the pit, it being close to the center on one end it should not get too cold. Our low temps are not severe enough to ever need 4" or 6" foam, but three would be nice.

Ken Fitzgerald
01-29-2004, 2:40 PM
Bobby, try some of these websites:

www.radiantdirect.com
www.radiantec.com
www.radiantcompany.com
In the design sections they explain how to design and why. I'm not recommending any of them. It's just where I was able to glean some information about radiant floor heating systems.

also try going to taunton books....finehomebuilding they have an article on radiant foor heating.

Good Luck!
Ken

Arvin Brown
01-30-2004, 1:03 PM
The insulation is not fiberglass insulation mixed in with the concrete. The insulation that has been mentioned is insulating styrofoam board (nice to have it 2" thick) that is placed on the ground prior to pouring the concrete. This acts as an insulating barrier to the heat going to the ground - thus forcing it up into the room. There is concrete that you can purchase that has small poly fibers in it. It is suppose to increase the tensile strength of the concrete, and it does - but not as much as re-bar. I would be very cautious with putting styrofoam up the edge of the concrete between the ground and the top of the slab. Check with your local termite company - termites like to eat their way up through the insulation into the walls. This was done on my home in Atlanta to insulate the concrete slab of the house and I had to remove it to sell because I could not get a termite bond!

Robert Ducharme
01-30-2004, 8:45 PM
I installed in floor tube radiant heating in my house when I built it. There are 7 zones to support 6000 square feet. Below the slab are 4' x 8' x 2" slabs of foam (real exciting one day when it was blowing). Above that is the steel mesh the tubes are tied to. Near the boundrys of the room the tubes are spaced on 6" intervals with 12" in the remainder of the rooms. This system uses a 275,000 BTU boiler which also handles heating the hot water maker. House is at 7000' in the mountains of Colorado.

Advantages:

Radiant tubes do not blow dust around.
Temperature is very stable because of the large heat sink and very comfortable.
The system is very efficient and less costly to run.
If the heat is left on, the floor and equipment is heated which becomes a large heat sink. This allows any cold air coming in due to DC exhausting outside to be heated quickly. This helps keep the temperature very stable and comfortable.
Minimal moving parts.
Extensible to use solar heating to heat the water supply.
Do not need to have pipes in the overhead so works well with short ceilings
Heat closer to floor instead of ceiling
Moisture levels in building easier to control since air not being dried by heater.
Easy to split into zones to heat areas at different temperatures.


Disadvantages:

When bolting equipment to the floor, need to make certain you do not drill through one of the tubes. These are sometimes hard to locate even if you take pictures.
The lag time between time turned on and until everything is up to temperature can be significant. Especially if a large area.
More costly to install than other systems.
The zone values sometimes need to be lubricated.
The floor is hotter than the room so if washing the floor, it can sometimes dry too quickly (wife's complaint)
More Complex to engineer because the water is re-circulated without being heated. This requires fiddling around with the mixing values until it is working optimally.
Need to leave system on - would not trust using glycol to avoid freezing.
May be hard to tell when on or off if not located where you are working.
Insulation below concrete stongly recommended.
Hard to retrofit into existing structures. Although it is possible to place it on top of exising flooring and then pouring 1.5" of gypcrete on top.




I think it all depends on your expected amount of time in the workshop and your climate.

To eliminate some of these problems in my workshop, I installed infra-red radiant heating tubes overhead. These systems are about 16' above the floor and have the following advantages and disadvantages:

Advantages:

This does not blow dust around.
The building starts feeling warm within 15 minutes. This is because the individual is heated (as well as the equipment). Therefore, lag time is eliminated.
If the heat is left on, the floor and equipment is heated which becomes a large heat sink. This allows any cold air coming in due to DC exhausting outside to be heated quickly.
Cheap and easy to install (compared to floor radiant heat).
Easier to install than forced air.
If liquids are heated in separate area, do not need to leave the system on. This is key for intermittent use of the workshop.
Easy to tell when on or off.
If bolting equipment to the floor, no need to make certain you do not drill through one of the tubes.
Very simple mechanically.
Not necessary to place insulation below the concrete - although it would not hurt (except the wallet).
Keeps you heated even if the door is open and cold air is blowing in.


Disadvantages:

The level of temperature from one end of the system to the other (depending on the length) can be felt.
Slightly more inefficient and therefore more expensive to run than other systems.
Not extensible to use solar heating of the water running through the tubes.
Need to be careful not to have burnable things too close to it. Once over 20 feet from the burner, can be no closer than 1 foot.


I attached a picture showing one of the two sytems I put in my workshop. These can either be straight or have bends.

Robert Ducharme
01-30-2004, 8:46 PM
Forgot to mention that the overhead radiant system is a 75000 BTU heater with 75' of tube providing the radiant surface.

Bobby Hatfield
01-30-2004, 9:38 PM
Anybody have experience with radiant floor heating in a new concrete floor ? Thinking of using it for heat in new shop, with 16' ceiling with the open attic, to heat the shop with stoves will cost more than the shop. Curious about zone heating, like heating the area with machines only on days when milling parts, then assembly when needed.

Thanks all, for the info and web sites for radiant in floor heating. I am convinced its the way to go, hopefully here in Arkansas it will be a reasonable cost to heat the shop, I understand the initial installation cost is more but the savings over time should make up for that.
I have yet to find anyone in this local area with experience installing this type of heating, small town where everyone knows who is kin to who, we are down to one woodworking/cabinet shop now, mine, going tomorrow to the auction of equipment of the other shop who's owner was allegedly stabbed to death by step son. May have another Grizzly, Davis-wells, Foley-Belsaw, Powermatic and Rockwell-Delta, tomorrow night if my bids are highest.