Drying wood on a radiant slab

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I got the barn slab energized last Friday night for the first time. It's 1800 sq ft and has two floors. This winter i will only heat the first floor. My wood supply may be a little shy this year due to the extra building so I'm going to need to get some green oak and maple into the barn for late winter burning. Has anyone tried seasoning on a warm slab? I keep the barn at 50-55*. The walls are R19, slab has 2" rigid foam below and on edges,no insulation between floors, R38 in attic. Any tips would be greatly appreciated.

thanks, Ed
 
I think this will work well. The only thing to be aware of is that you will be dumping all that moisture into the building and it may start condensing on the walls, etc. You may need/want to have some way to exchange air and get that moisture out of the building. The nice thing is, as you bring cold air into the building at, say, 50% relative humidity, as it warms up to the room temperature, the relative humidity drops dramatically.
 
I don't see how it would work any different than a building heated with forced air, baseboard, etc. It's not like the floor is hot to "cook" the wood... at least mine isn't!
 
I put in 12 cord in a wood room in my basement (radiant floor heating). If there's any moisture in it, it comes out quick! Yes, I get a little moisture on my windows for a few days, but that's it. No secrets - mine is just stacked in tight rows on the floor and up against the walls.
I've put some green wood in the back end of the wood room before, and it's dry by the time I get to it 3 months later.
 
NATE379 said:
I don't see how it would work any different than a building heated with forced air, baseboard, etc. It's not like the floor is hot to "cook" the wood... at least mine isn't!

Actually the radiant floor heats much differently. There are three means of heat transfer or migration: convection, conduction and radiation. Forced air heating is almost solely convective heat transfer - it only heats the air - that is why it is generally considered the least comfortable. In-floor heating is almost solely radiant heat transfer so that it heats the 'stuff' in the room, not just the air. In the same way that the sun feels warm on your face on a cold winter's day. Because the table, chair, floor, shop equipment, tools, etc. are warmer to the touch with a radiant floor system, it is generally considered to be the most comfortable - even with lower air temps. Baseboards are one part radiant heat and another part convective and, as you might guess, provide a level of comfort somewhere between in-floor and hot air.

So, the wood piled on a radiant slab will be warmed both by the radiant heat and by the conduction of slab to wood contact. Since the wood itself will be heated more so than if the room were heated with a forced air system, the wood should dry more quickly.

This is all pretty theoretical, I guess. For example, if you had a Modine heater blowing warm air across the wood pile it would likely dry more quickly than even the radiant slab.

Enough of a babble, I just wanted to point out that there is, indeed, a difference.

Chris
 
Radiant heat dries wood quickly. I stack wood in my radiant garage with a box fan blowing on it and a dehumidifier running and it works very well.
 
thanks for all the replies guys. Do you think a 50-55* slab will get the green stuff dry in 2 months or should I raise it to 60*? A friend told me to expect to burn 10btu's per sq ft for every degree I want to raise the 4" thick slab. Any truth to that?

Ed
 
That was my point exactly.

70* air temp in the shop is 70* whether it's heat from the floor, wood stove, baseboard, etc. About the only slight difference would be that most shops don't have 70* floor temp if the air temp is so the wood toward the floor would be a bit warmer.

If I take a frozen 1ftx1ft block of wood and set it in a 70* room heated with forced air, that block of wood will be 70* after a bit. If I do the same with a radiant floor heated room, same results.


Tarm Sales Guy said:
For example, if you had a Modine heater blowing warm air across the wood pile it would likely dry more quickly than even the radiant slab.
 
Green wood takes a good solid year to season outside, that is with summer temps 70-80*, wind blowing on it, etc.

How do you figure that you can do it in 2 months at 55*? Kiln drying hardwood can take that long and kiln temps are 3-4x your garage temp.


EForest said:
thanks for all the replies guys. Do you think a 50-55* slab will get the green stuff dry in 2 months or should I raise it to 60*? A friend told me to expect to burn 10btu's per sq ft for every degree I want to raise the 4" thick slab. Any truth to that?

Ed
 
Re-split wood and stack loose. That will help dry faster and also let you burn sooner than the ideal 2 year dry time.
 
Although drying can work on a radiant slap, it also can work in a kiln, in an oven, or sitting in the living room -- the point is, why use hard worked and paid for energy to dry wood? Cut, split, and dry it outside where the drying is free with wind and sun. Burning wood to produce heat to dry the wood you're going to burn makes no sense to me. Seems to defeat one of the major purposes of burning wood.

If you don't have enough dry wood this year, take it easy and do better next year. My goal is to always burn firewood dried 2 years outside.
 
Aarrgg, I'll just fill the oil tank when the good stuff runs out in the spring. I started with a three year supply of wood but fell behind after working out of town for a year. Spent the following year trying to catch up on other projects in town. Then I added the barn into the loop. Gotta go, I've got wood to split for next year and the following year............
 
It'll work just dandy. You will need to watch the relative humidity in the room though and provide some ventilation air from outside.
 
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