Radiant floor in shop

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RowCropRenegade

RowCropRenegade

Feeling the Heat
Mar 19, 2008
305
Southwest, Ohio
Been busy working on the new 80 by 90 farm machinery shop.

There has been great debate about only insulating 12 feet around the perimeter. Which will leave the center uninsulated. I have read the threads about this "heat sync" on hearth before. However, I don't recall them having 900 square feet in solar panels to charge the center. According to the commerical heating guy who helped me with my Garn project, we can charge that center starting in September and use those reserves along with the solar panels to heat the shop.

Thoughts, ideas?

We will probably do the insulation next week. Trying to decide to go the safe route and insulate the entire thing and not get full benefit from the solar or only do the first 12.
 
RowCropRenegade said:
Been busy working on the new 80 by 90 farm machinery shop.

There has been great debate about only insulating 12 feet around the perimeter. Which will leave the center uninsulated. I have read the threads about this "heat sync" on hearth before. However, I don't recall them having 900 square feet in solar panels to charge the center. According to the commerical heating guy who helped me with my Garn project, we can charge that center starting in September and use those reserves along with the solar panels to heat the shop.

Thoughts, ideas?

We will probably do the insulation next week. Trying to decide to go the safe route and insulate the entire thing and not get full benefit from the solar or only do the first 12.
Click to expand...


I'd insulate the whole slab. I doubt that you will store enough to carry you very far into the heating season, and when the wood or solar kicks in, you want the energy to go directly to the slab/ building space, not going into the ground.

Winter months in that area don't offer a lot of solar, so put it directly to the load, the insulated slab. Same with the wood powered heat energy.

Be sure to get a good slab edge insulation detail, that is a huge heat loss area as it sees the low -9 ambient conditions experienced in your area. 2" of foam with a Z flashing to protect the exposed edge, down a few feet at least.

Down the road someone may want to heat that building with gas, lp or other fuel sources. They will appreciate the entire slab being insulated.

hr
 
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I believe the $$$ saved on 2" foam will be payed out in heating costs many fold over the life of the building. Insulate the whole thing, you can't do it after the pour. Remember that radiant heat moves in all directions, so heated earth below a slab will not return all of that heat to the slab, most will be dissipated.

TS
 
Insulate it. The ground under the building is always cooler than the space being heated.
Even small temperature differences are going to syphon heat away from the slab.
You only buy insulation once. It is a cheap date and you cannot easily go back and retrofit a slab.
 
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It all depends on what's underneath; if it's wet down there, the water will carry your heat away as it flows very slowly through [got that from a geological engineer who specializes in this].

If dry, it might have a positive effect.

The thing is, you'll only know after your whole project is done and you run it for a year or two; and then it's too late to go back.
This is why builders tends to be very conservative.

So I agree with the above responses.
 
Two things come to mind right off the bat....

1: Water table ...nuff said.

2: The heat sink idea only works to a decent degree if you can basically insulate all the way down around the sides of it or else sink deep vertical loops and store the heat all summer. Think of the area under the pole barn like a box you want to store heat in and you get the idea. Not saying it doesn't work. I read of a whole village in far northern Canada (think Eskimo country) that is heated in that manner. They sank vertical loops down about 500' if I recall, in a pattern under the village. Those loops are heated with solar panels (lot's of 'em) all summer long and they get the earth way down there to about 120*. Each of the buildings in the village were designed as near zero heat loss structures so the heating load is very very low. During winter they pump "heat" from that underground storage into a district heating system that distributes to each of the structures in the town. Seems to work pretty fair from what I have learned following up on the project. BUT! This was a highly engineered project and done with buildings that have low single digit heat loss per sq foot.

So. I would really recommend insulating the whole thing. I would pay special attention to the edges of the slab as most of the heat loss occurs there. Make sure you get vertical insulation down at least a couple feet. Go 1-1/2" around the perimeter and then 1" through the center. In your location you could probably get away with 1" through the whole floor if you get the edges done right.
 
I'd insulate it. There is no going backwhen it's done. Unless I could talk to people in the area that did it the other way and were happy with it.
 
+1 on the on insulation Row Crop.
You will never regret getting it in there. One spank in the wallet & done.
Other way around a lifetime of shoulda, coulda, woulda + the wallet keeps getting touched up for higher operating costs...fuel needs.
P.S. Heaterman is dead on about the perimeter...dont forget that insulation.
Up here I install more but in Ohio 1.5" & 1" probably does just fine. Have a good one.
 
Insulate for sure. We did 2" on my house and garage, I wish I had done another layer for 4" total.

Floor heat is nice, though the SLOW SLOW SLOW response time can be an issue. I ended up putting a small hanging heater in my garage to help out with recovery time. Before that, I'd pull a vehicle in when it's -20* out and it'd take 4-5 hours for the garage (and vehicle) to be up to room temp (55-60*). With the small heater it takes maybe an hour.
 
Renegade: I forgot to mention taping all the seams in the foam board with TUCK tape (the red stuff). That will help with moisture infiltration & the heatloss that results from same. Esp. if you are in clay based soils.
 
It's also important to prep the soil beneath the insulation. Non wicking material such as course crushed stone and course gravel in order to keep any moisture away from the heated slab. Also good perimeter drains with plenty of non wicking material for backfill. One or two layers of 6 mil polyethelyne sheet below the insulation. Any moisture will wick away your heat, never to return.
Here in Vermont we have a mix of soils and one observation I have made over the years is that structures built on well drained soils are much more efficient in terms of heating than buildings built on clay based "wicking" soils.

Those with porous soils get their vegetable gardens planted about two weeks earlier in the spring but those with wicking soils have a nicer lawn:).
 
heaterman said:
Two things come to mind right off the bat....

1: Water table ...nuff said.

2: The heat sink idea only works to a decent degree if you can basically insulate all the way down around the sides of it or else sink deep vertical loops and store the heat all summer. Think of the area under the pole barn like a box you want to store heat in and you get the idea. Not saying it doesn't work. I read of a whole village in far northern Canada (think Eskimo country) that is heated in that manner. They sank vertical loops down about 500' if I recall, in a pattern under the village. Those loops are heated with solar panels (lot's of 'em) all summer long and they get the earth way down there to about 120*. Each of the buildings in the village were designed as near zero heat loss structures so the heating load is very very low. During winter they pump "heat" from that underground storage into a district heating system that distributes to each of the structures in the town. Seems to work pretty fair from what I have learned following up on the project. BUT! This was a highly engineered project and done with buildings that have low single digit heat loss per sq foot.

So. I would really recommend insulating the whole thing. I would pay special attention to the edges of the slab as most of the heat loss occurs there. Make sure you get vertical insulation down at least a couple feet. Go 1-1/2" around the perimeter and then 1" through the center. In your location you could probably get away with 1" through the whole floor if you get the edges done right.
Click to expand...


this is the place:

http://www.dlsc.ca/

really cool place. wish I had that install job.
Karl
 
dougstove said:
Heaterman: Okotoks Alberta is practically the banana belt; very sunny, with hot dry summers. You would have to go ~2500 km farther north to find an Inuit village...
Click to expand...


So much for my Canadian geography and spewing stuff out from memory :eek:
 
I thought the same thing HM..........

TS
 
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