[Strawbale] re re Sask. foundations

Michael lough michaelklough at sympatico...
Fri Feb 17 17:21:06 CET 2006

Donald said

++I think you said at the start that rammed tyres were out due to
leaching etc.

I think you may be mistaking me for Mark (Bigland-Pritchard)? A
flattering mistake however.

I do recall however that Mark did outrule the use of tires on the
basis you refer to and I respect his judgment on this.

It is likely that there is some reaction between  slightly acidic
rainwater and the tire material? If this produces a petro chemical
"soup" which then descends into an aquifer then we have to say that
over time it will not be good? The use of used tires is seen in
industrialised countries as a good thing as it turns a non
biodegradable item into a useful item. This may be true if the tires
are used in an above ground situation and are not exposed to UV or
moisture but I would say that it would not be a good idea to use
used tires if they are to be in contact with rain water which then
goes into the ground after washing off the surface of the tires. On
the other hand perhaps they could be coated first?

Perhaps in view of the number of tires produced annually it is
understood that one may as well use them in the ground as it makes
little difference to the environment any way at this point?
Certainly as we consider that oil tar or other bituminous material
starts off in the ground? I would think it might be site specific?

I would be less worried if the tires were to be used in a desert
with little rainfall and moist air evaporated quickly. Still not
perfect but perhaps leaving the tires in a large dump to catch fire
occasonally is less ideal? I am not sure of the state of the art in
used tire recycling but I think I have seen a few tire "mountains"

++I have *never* seen any data on this issue - but I'd like to as I
intuitively feel there has to be outgassing or something from tyres.

The fact that we have never seen any data does not mean it does not
exist? It may be that tires off gas. I can tell you that I have
heard that earth "ship" owners that have used tires under plaster in
wall systems  with earth berming have reported that in high Summer
you can smell them.

++FWIW, I'm building a 7m x 5m sb (looking to plaster in a few
weeks). The foundations are rammed tyres with railway sleepers on
top. There is a LOT of work in ramming those tyres...

I cant imagine ramming a three bedroomed earth ships worth?  ;^)

Not sure where you are but railway sleepers (wooden?) and/or old
telelegraph poles in Canada are pretty dangerous things to use
environmentally speaking. They are I believe soaked in a creosote
mix and the older ones used arsenic in the mix I think as well, like
pressure treated  (PT) wood used to here.

++don't underestimate that. If I were to do again, I'd be looking
around for alternatives.

The most ecologically sound method would employ only natural locally
available materials for a foundation. This might include rocks or gravel or 
shells as a drainage channel. On top of this would be a short wall
which would support the perimeter which would support the walls
above. Any deviation from this is a compromise.

If we are not perfect then it is a question of the degree of our
imperfection? I do not believe that nature has ever produced natural
insulation for under floor use as good as some man made products. Its
a trade off?

Concrete posts or quarried marble columns supporting a sustainably harvested 
"living box" with underfloor straw bales as insulation could be the
answer?  The quarry would have to use a solar powered diamond saw


Michael Lough

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