[TheForge] RE: radiant heat

[ed]

 I built my new shop (now three years old) with Radiant heat in the floor.  If
you don't insulate on the bottom end, you'll be sorry later.  I worked HVAC
for a number of years and installed radiant heat on several homes and shops. 
There were a few who did not insulate the bottom of their slabs, and their
systems ran constantly. Without insulation under the slab, it's almost like
you don't have a heating system...the ground will suck the heat away terribly.
 It doesn't matter how deep you put it, without some type of insualtion the
earth will suck the heat out of the slab faster than the system can keep up.

  My shop has 2" polystyrene under the slab, and 1 1/2" veritically around the
outside to ground level. (monolithic slab)  I still have about 2" of exposed
concrete around the bottom outside edges of the building, and even this makes
a lot of difference when the weather turns very cold.  

  I built the whole shop myself....
24" footers, slab that tapers from 12" thick on the end that the machinery
sets on, to 6" on the opposite end.  2" insulation on the bottom, with welded
mesh on top of that, with the pex tubing zip tied to the wire mesh.  A second
layer of wire mesh, with the concrete being 7 sack, fiber mesh.  The outside
edges have 1 1/2" insulation to ground level (I wish I would have gone the
entire height of the slab for better insulating purposes.  My radiant system
contains all the normal componets, with the exception of using a 50 gal
residential hot water heater as the heat source.  Boilers are better, but just
too expensive to purchase and maintain.  I keep the thermostat in the shop set
on 55F and the heat works great until the temp gets below -30...then it has a
hard time keeping up.  

  Radiant floor heat is without a doubt the most comfortable heat you can
install.  On the down side, it does not work quickly.  Generally it takes 4-6
DAYS for the system to level out on a 10 degree increase in temp. 
Recommendations call for an allowance of 10-14 days at a set temp for the the
systems to stabilize. 

Ed Caffrey, ABS Mastersmith
"The Montana Bladesmith"
http://www.caffreyknives.net
ed at caffreyknives.net

---------- Original Message -----------
From: "Roger Olsen" <erik at methow.com>
To: "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Mon, 27 Mar 2006 11:56:04 -0800
Subject: [TheForge] RE:  radiant heat

> To: Sponsored by ABANA
> Subject: Re: [TheForge] Re: WAAAAAAAAY OT (while we're talking about
> heat
> 
> Justin Fellenz wrote:
> 
> >>Andy and Frosty and anyone else with in-floor radiant heat,
> >>
> >>  Do you have insulation horizontally under the slab or no? I'd like
> >>to avoid it since it's expensive and it sounds like it makes it more
> >>likely the slab will crack under hard (power hammer) use. I'm told
> >>you need it but it seems to me that insulation vertically on the
> >>fronst walls 3' deep should isolate the 6" of crush and 3' of earth
> >>pretty well.
> >>
> >>  JRF
> ____________________________________________________________
> 
> You most definitly want insulation under the concrete.  If you don't 
> put it in the ground will continually suck the heaat from your 
> system and cost you a fortune to heat.  That mistake has been made 
> by others in the very cold valley where I live.
> 
> As far as under the hammer you shoud isolate a separate pad just big 
> enough for your hammer and much much thicker depending on the size 
> of your hammer than the rest of your floor.  I have a 4 inch slab in 
> my shop but I have 2' under my 100 lb hammer and 18" under my 25 lb hammer.
> 
> We have radiant heat in the house and I love it but why someone 
> would put it in a blacksmith shop is beyond me.  I have spells where 
> it does not get above zero degrees F. for weeks on end every winter 
> and cold snaps to as much as 30 below.  I run a propane forge and 
> between that and the body heat radiated by working I still end up 
> with the doors open.
> 
> my 3 cents worth.
> 
> Roger Olsen
> 
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------- End of Original Message -------