[Greenbuilding] Flip-flops bad for feet, life safety ... (was Re: Heat pump vs radiant)

John Salmen terrain at shaw.ca
Mon Jul 29 10:12:34 MDT 2013

Tire recycling led to a lot of odd and inappropriate products - I did some
research on playground stuff (surfaces made of ground tires) a while back
and found that there was significant outgassing and leaching of both
chemicals and metals (hydrocarbons, cadmium, lead, etc.). Similar info and
concerns on recycled tire roofing.


I've had wonderful results with clay based finishes moderating humidity in
bathrooms and kitchens. Basically moisture in the air is pressure driven
into the less moist wall and condenses to fill pores in the render. If the
render were less porous the moisture would condense on the wall surface. As
the room air eventually becomes less humid than the wetted wall the moisture
is driven back into the interior air. If the wall render is continually
saturated it will lose structure and probably develop some toxicity. I
remember reading that mold was found growing between layers of latex paint
in bathrooms.


The walls in an earthen home would have to be engineered to provide the
right amount of porosity to store seasonal moisture and would have to be
well isolated from exterior moisture sources (including ground - 'rising
damp').  The soils need to be free of contaminants as they will degrade and
pollute the air and depending on the amount of potential saturation would
have to be isolated from materials that could be degraded with seasonal
contact with high amounts of moisture. It seems that humidity levels can be
moderated in the 40-70% range in an earthen home. 


Using the properties of a material in the best way possible is always a goal
and earthen building lends itself to moderating climate but it depends on
the nature of the soils used and how they are put together - I think its an
exciting material to work with but phenomenal amount of design work involved
as we don't have a lot of historical knowledge, not just dirt heaped in a



From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org]
On Behalf Of Alan Abrams
Sent: July-28-13 9:55 AM
To: archilogic at yahoo.ca; Green Building
Subject: Re: [Greenbuilding] Flip-flops bad for feet, life safety ... (was
Re: Heat pump vs radiant)




well, here's a thought (and a flip flop from my initial reaction); that the
huge volume of soil stockpiled in the tires (and used as interior wall
finish?) could be a hygrometric flywheel.

Hygrothermic flywheel ?  Ehhhh... don't think so.

For hygro-anything contribution to space conditioning, the hygro and the
therms would first have to make it past the thick, air/moisture-impermeable
petro-chemical stew barrier that has been reincarnated into condoms for dirt
... and that's after assuming that they first make it past the thick layer
of plaster (which optimistically would be detailed to be an effective air
barrier) first.

If the owners are keen on having pounded dirt for their walls, rather than
looking at a model designed for the desert southwest, they might give some
consideration to a model designed for a climate with which they have more in
common ... say like the insulated-core rammed earth buildings



setting aside other objections for a moment, the flywheel notion was based
on two assumptions:


1. that the interior finish would be a vapor permeable sand and clay mix, or
a lime plaster.  ((recalling the time Jim Chaddick, my old boss and
reluctant mentor, drove us out to some quarry out beyond Abiquiu, deep in
Georgia O'Keefe country, to fill the truck with a local clay called "tierra
blanca."  (At the time, I specialized in pick axes and wheel barrows).  Jim
made this substance into a slurry which he used as a finish coat for the
interior of his adobe home.  There must have been some mica or similar
mineral in it, which gave the finish a wonderful luminosity.))  


and 2. that the running bond pattern of stacked tires of odd diameters and
widths would leave plenty of pathways for moisture to pass in and out of the

All this does raise the issue of outgassing--if the finish is
permeable--and--the house is PH air tight--then will your standard issue
15-20 CFM's per person ensure good air quality?




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