[AT] Radiant heat

[Indiana Robinson]

On 20 Oct 2005 at 13:19, Andy Glines wrote:

> Well, I finally have my own shop building.  I bought a home
> that came with a 30 X 50 pole building.  The building is
> nice but the PO never got around to putting a floor in 
it. 
> It is my plan to install a concrete floor ASAP.  I hope 
that
> I can resist the urge to put "stuff" in there before 
getting
> the floor.  There is already a wood stove in the building
> that I plan to keep.  I am considering installing the
> plumbing for a radiant heat system in the concrete floor. 

> The system may not be used right awat but the plumbing 
will
> be in place.  I'm looking for lessons learned and tips 
for
> this project.  I know that there is some ATIS experience
> with this topic.  My initial thought is that the wood 
stove
> will provide the heat for the floor as well.


	No reason why it shouldn't... You will have to add coils 
or something similar to it of course but that is not too 
difficult. If we knew the type of stove it would help us 
think about that part.
	I assume that you will use PEX tubing in the poured 
concrete. I plan to use 1/2" PEX.  I was looking at it for 
current prices last week and was surprised how reasonable 
it was compared to the old PEX of years ago (the stuff that 
failed). At Menards it was about $58 for a 250' roll of 
1/2". One of the main things is that you must NEVER put a 
splice in the tubing in the floor. If you need to splice it 
come up the wall and splice it and go back down. Some folks 
use valved manifolds to control the amount of heat in 
different parts of a house. I don't plan on being that 
sophisticated in a shop. I only plan to heat to about 50 
degrees most of the time. I like the "KISS system" and 
figure to run the line to the part of the shop I would want 
the warmest first and the areas I don't care as much about 
last. I can't do it on my existing building but on a hoped 
for new addition I want to run a line along under the 
bottom of the overhead door to keep it from ever freezing 
down to the floor. I also like the concept of a perimeter 
line too. Consider being sure that a loop runs near any 
water hydrant too.
	Some folks run an antifreeze solution in them, some just 
use plain water. If plain water and you have a float valve 
to keep the system full consider running a line past your 
sink (you need a sink) and tapping into it for a warm 
source for hand washing water. There are hundreds of 
variations and possibilities. In part of mine I intend to 
run the heated water into buried tanks rather than floor 
loops because part of my floor is already there. The 
blacksmith shop part will probably always be crushed ag 
lime for the floor.
	Be sure to insulate the perimeter of your floor with foam 
down at least 2 feet and 4 feet if possible.
	Don't forget to put a vapor barrier under your floor. If 
the floor is to be poured on pea gravel etc. I like the 
vapor barrier under the gravel.
	BTW the PEX is reasonable and so are the fittings but the 
fitting compression tool will hurt a tiny bit... :-)   Not 
terrible but the 1/2" tool was I think about $100. You use 
a compression ring and after compressing you use a "go - no 
go" gauge (cheap).
	Keep the pump size down to something that will operate 
cheaply. If you stick a 1/2 HP motor pump on a system using 
say 1/2" pipe it will work too hard and cost an arm and a 
leg to run. Such a system needs no pressure to speak of... 
Just the head pressure of the height of your system. In 
something like a shop system you will have an elevated 
supply tank higher than any other part of your system. I 
plan to feed mine with a common float valve. Heck, you 
could even put in an elevated bathroom and use the commode 
tank as a supply...   :-)
	I have thought about going to the opposite corner of the 
shop from the stove and hanging an automotive radiator with 
a small fan behind it and feeding a heat line to it in the 
bottom and out the upper outlet. (feeding from the bottom 
makes sure all of the radiator gets warm).

	One of the email list I own on Yahoo Groups is called 
"Cheap Shelters". It has 825 members some of who are 
professional builders and architects. This topic gets 
discussed fairly regularly there.
cheap-shelters-subscribe at yahoogroups.com

	You don't have to worry about "putting" stuff in there 
before you are ready... It will suck in there over-night 
all on its own.   :-)


- 
"farmer"
Hewick Midwest

The master in the art of living makes little distinction 
between his 
work and his play, his labor and his leisure, his mind and 
his body, 
his information and his recreation, his love and his 
religion. He 
hardly knows which is which. He simply pursues his vision 
of 
excellence at whatever he does, leaving others to decide 
whether he 
is working or playing. To him he's always doing both. 
 ~ James A. Michener, attributed

Francis Robinson
Central Indiana USA
robinson at svs.net