[Cob] Radiant heat floors

[ocean]

INCORRECT: Copper suffers a severe chemical reaction with the caustic 
elements in concrete and literally dissolves when in contact with 
concrete.  No one embeds copper pipes in slab heating systems anymore.

On the other hand, PEX (cross linked polyethylene) tubing has been used 
successfully in millions of homes and commercial applications for 
concrete-embedded radiant water heating ("hydronic heating").

In the European Union, PEX is also the standard used for all potable 
cold and hot water systems, since the EU banned PVC due to its highly 
toxic quality.  Manufacturers give the "low" lifespan of 20 years for 
PEX, but when embedded and protected from UV exposure one could expect 
it to last indefinitely.

Embedding in a slab is easy, one simply zip-ties the flexible PEX to a 
steel mesh (6" x 6" works well) and then pour the slab over the mesh 
and PEX.  We installed a hydronic PEX system into a fairly drafty room 
in my garage and now it's the coziest room in the house!

Good luck!

Ocean Liff-Anderson
Wildfire Restaurant, Corvallis Oregon
http://www.wildfirefood.com


On Jan 29, 2007, at 10:48 AM, joe r dupont wrote:

> WRAP THE COPPER PIPE WITH PE FILM..
> I THINK THE FAILURES ARE MORE FROM ABRASION CAUSED BY EXPANSION AND
> CONTRACTION OF THE COPPER  RATHER THAN THE  CHEMICAL ASPECT OF IT.  IF
> THE CONCRETE IS DRY.. REALLY DRY THAT WOULD BE MINIMAL.
>
> On Sun, 28 Jan 2007 21:20:20 -0500 "paul" <dotpaul at paulleblanc.net>
> writes:
>>
>> ----- Original Message -----
>> From: "Yun Que" <yunk88 at hotmail.com>
>> To: <dkdale at sbcglobal.net>; <coblist at deatech.com>
>> Sent: Sunday, January 28, 2007 1:12 PM
>> Subject: RE: [Cob] Radiant heat floors
>>
>>
>>>
>>>   Cat here!
>>>
>>>
>>>   Frank Lloyd Wright used copper tubing in concrete.  the
>> chemicals in
>>>   the concrete degenerated the copper and the systems failed over
>>>   time...
>>>
>>
>> Bummer!
>>
>>
>>>   Their are electrical tape systems that will put a grid of
>> electricity
>>>   under you the same way an electric blanket works.  Not my
>> favorite
>>>   choice!
>>>
>>
>> Do you stand in a puddle of water to get the full effect?
>>
>>
>>>   You could look into copper tubing in a gravel base with clay
>> (cob) or
>>>   terracotta tile with clay mortar.  More expensive for sure but
>> will
>>>   last forever and could be repaired if their is failure.  No
>> repair in
>>>   a radiant heated floor is going to be easy.
>>>
>>
>> So nobody has ever devised an "easy maintenance" scheme?  I can see
>> that
>> it's pretty challenging.
>>
>> I once stayed in a cottage in Oregon that whose floor was heated by
>> a
>> geo-thermal spring.  All you had to do was turn a knob and the water
>> from
>> the hot spring would fill the tubes (made of what, I don't know).
>> The place
>> would hit 90 degrees if it wasn't bone chilling cold out.
>>
>>
>>>   My own choice was to lay dry clay pipe in gravel overlaid with
>> tile in
>>>   a clay mortar...then allow heat to circulate into the pipe from
>> a
>>>   lower level green house...this is to be a passive solar or wood
>> fired
>>>   system.  taking the subterranean 52+/- degrees and heating it.
>> The
>>>   smoke from the fire would be exhausted out of the cellar or
>>>   greenhouse, using a masonry stove for greatest heat efficiency
>> and the
>>>   heated air from the confined area would heat the level above
>> thru
>>>   vents into the floor pipes... No smoke would ever be in the
>> house.
>>>   It's a concept only!  I am working with property using a
>> stepped
>>>   hillside farm with southern exposure....The idea is to have as
>> few
>>>   moving parts as possible and even if the clay pipes crack or
>> become
>>>   separated under the floor they would still function. The house
>> would
>>>   have to be built with the heating system as a paramount design
>>>   element. My choice is eight sided and up to get the most space
>> with
>>>   the least foundation and roof, keeping the heat source in the
>>>   center...
>>>
>>>   Anyone out there see possible flaws in my plan?  When I dream I
>> tend
>>>   to be an optimist!
>>
>> Clay pipes?  Never heard of them.  I'm amazed at how much I don't
>> know.
>> Yipes.
>>
>> And they'd still function if they broke? I guess you can "see" how
>> they are
>> laid in there (sealed apparently.)
>>
>>
>> p
>>
>>
>>
>>
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>>
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