RE: [GBlist] foundation insulation boards

["Ralph Bicknese" <ralph.bicknese@christnerinc.com>]

<Physics tells us that "coolth" does not migrate, it is warmth that travels.
So since the footing/foundation wall/slab is a big heavy chunk of
warmth-absorbing material, whether or not it's insulated from the outside,
shouldn't we be talking about isolating our warm inside air from this pig of
an energy-eater?  In other words, build a wall on the inside and a floor
over your slab?>

Physics is physics but one cannot just take it at face value without
thinking about the practical applications.

Left uninsulated a concrete basement wall will be cool winter and summer.
It will be colder in winter than in summer because the ground is colder.
Even though physics tells us that temperature travels from hot to cold, the
wall is still cold.  The cold is getting into that wall in some way;
conduction from the cool ground to the warmer wall.  True, the heated air is
giving up some of its heat to the cool ground.  But in practice, is not the
cool ground also giving up some of its coolth?  Regardless of what the
physics suggest will happen with the flow of temperature, the wall is cool.

If a person wants to use the thermal mass of a wall or a slab to help
moderate the high and low temperature swings one needs to keep the mass
within the thermal envelope.  In other words, insulation should be placed
outside the mass. If taking advantage of the mass is not important then one
could insulate inside the mass.

I personally like the mass inside.  Besides having the ability to use the
mass for thermal storage, I can also see if there are any problems with the
mass (cracks, water penetration, condensation, mildew, etc.). I have seen
too many problems with basement walls and slabs to take this lightly,
including condensation under carpeting on uninsulated basement slabs.

Cheers,
Ralph Bicknese



-----Original Message-----
From: Kathleen Mitchell [mailto:molasses@speakeasy.org]
Sent: Sunday, February 24, 2002 1:45 PM
To: greenbuilding@crest.org
Subject: Re: [GBlist] foundation insulation boards

"Placing insulation on a basement wall and under a slab does not create a
thermal break between footing, wall and slab and the coolth will wick into
the slab and the base of he wall."

Physics tells us that "coolth" does not migrate, it is warmth that travels.
So since the footing/foundation wall/slab is a big heavy chunk of
warmth-absorbing material, whether or not it's insulated from the outside,
shouldn't we be talking about isolating our warm inside air from this pig of
an energy-eater?  In other words, build a wall on the inside and a floor
over your slab?

Insulating on the inside must open up a whole can of moisture worms, but
perhaps it's greener in the long run - that is, if it's possible to keep
your false walls and floors from rotting away without poisoning the
occupants with arsenic?  LCA, anyone?

A slab just seems like an insane waste to me unless you're using it to catch
and hold the sun's warmth, or you're using it in an unheated space.  But
then, I live in an area where the frost depth is only 18", and we don't have
to build basements...

-Kathleen Mitchell


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This greenbuilding dialogue is sponsored by REPP/CREST, creator of
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______________________________________________________________________
This greenbuilding dialogue is sponsored by REPP/CREST, creator of
Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
Environmental Building News and GreenSpec http://www.BuildingGreen.com
______________________________________________________________________