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RE: GSBN:Re: : slab edge insulation

I agree with Nehemiah, even though his name is difficult to spell.  In an
earlier post, we talked about how to effectively insulate the slab edge,
even though you might not insulate under the main slab.  Does Mr. Stone have
a source to the styrene material mentioned?


-----Original Message-----
From: GSBN [mailto:GSBN@...]On Behalf Of Nehemiah
Sent: Monday, March 10, 2003 8:07 PM
Subject: Re: GSBN:Re: : slab edge insulation

I beg to differ with John and John.  I did a fair amount of infrared
camera work a number of years ago to see where heat exits a building in
central California.  We would crank the heating system up to a little
bit above what one would normally heat a house to, and then film it
from the outside in the middle of the night.  The three greatest loss
sites for a "normally" insulated house (one that just meets the minimum
California requirements), were (1) the aluminum frames of windows, (2)
the slab edge, and (3) hot water pipes and other pipes (e.g., the
pop-off valve) near the water heater.  Slab edges, when the slab is
exposed to the night sky, account for a VERY significant portion of the
winter heat losses.  Slab edges, when they are tucked under a very wide
eave, account for a lot less.  And slab edges that are insulated, very
much less still.  If a person is going to have a a radiant floor
heating system, then they absolutely should insulate the slab edge.
There are products available that have a hard styrene material
surrounding the insulation.  The hard coating (1) looks good, and (2)
has a key that ties into the slab so that termites cannot pass between
the two building elements.  The insulation is used as the form when
pouring the slab.

Nehemiah Stone

On Tuesday, March 4, 2003, at 05:22 PM, John Swearingen wrote:

> I agree with John Straube about not using slab insulation in SUNNY
> California.  We have areas that have severe winters and deep frosts,
> but in
> most areas we are designing for cooling loads more than heating.
> Experience, as well as computer simulations, show about a 5F lowering
> of
> ambient  temperatures for four or five summer months when slab
> insulation is
> removed.  The corresponding increase in heating loads is usually
> minimal and
> only significant for a couple of months.
> John
> -----Original Message-----
> From: GSBN [mailto:GSBN@...]On Behalf Of John
> Straube
> Sent: Tuesday, March 04, 2003 1:35 PM
> To: 'GSBN'
> Cc: bainbrid@...
> Subject: RE: GSBN:Re: : slab edge insulation
> I would not use any insul below slabs in sunny california, but would
> use
> it on the stem wall.
> Protection is easy -- you plaster bales? Well you can plaster the foam
> too. The termites are a bigger issue, best solved IMHO with a peel and
> stick over the concrete and down the face of the foam/Mineral fiber 2",
> then plaster over.
> -----Original Message-----
> From: GSBN [mailto:GSBN@...] On Behalf Of Bob Bolles
> Sent: March 4, 2003 12:11
> To: GSBN
> Cc: bainbrid@...
> Subject: RE: GSBN:Re: : slab edge insulation
> Hi John
> You wrote"
> <snip>
>> "Finally, if you are using a concrete foundation, adding a couple
>> inches
> of foam or fiber insulation to the exteiror of the foundation is likely
> to be easier and high performance"
> Well, therein lies the problem
> If you place the foam on the exterior, first there is the appearance
> issue, as well as protecting it from damage. Then, I have to ask if
> this
> would potentially provide a path, behind the foam or through it, for
> termites, ants and other little critters?
> I believe that insulation under the slab is probably appropriate for
> cold climates, but I am working in sunny Southern California. How much
> insulation should we use, if any, below the slab.
> Regards
> Bob
> Bob Bolles
> Sustainable Building Solutions
> Bob@...
> www.StrawBaleHouse.com
>  "They that can give up essential liberty to obtain a little temporary
> safety deserve neither liberty nor safety"  Benjamin Franklin
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