E-M:/ More on oil on foundations

[anne.woiwode@sfsierra.sierraclub.org]

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Enviro-Mich message from anne.woiwode@sfsierra.sierraclub.org
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Again, thanks for the insights -- two more messages with good info:  
AW


Anne - just a couple of brief comments on the information sent to you.  I
think you know that I am a chemical engineer, which is the basis for these
thought.

I doubt any (oil) soaked into the cement, though traces might rub off and a
*very* small amount dissolves. The oil repels the water of the cement and
prevents adherence to the board.

> A tar-like substance is put on block and poured walls before they backfill.

This is probably asphalt, and is very insoluble. It would be like the "tar"
used in roofing, or for tree work, etc. I do not know whether it is used with
a solvent to thin it. If so, the solvent would probably evaporate as usually
the foundation is not backfilled until the sealant has been applied to the
whole foundation.

Neither used motor oil or asphalt are things one would want thrown into rivers
or lakes, but these uses are very minimal. I would be more concerned with how
the old concrete forms are disposed of.

***************

Most likely, the oil is being used as an ingredient necessary
for the release of plywood formwork from the cured concrete.  Most of the oil
will remain with the plywood, not the soil, and will effectively be reused the
next time the form is.  I don't know how the plywood will be disposed of after
half a dozen uses.

Your 8-10 gallons amount seems excessive, but may not be for a large building,
as it must be absorbed by the plywood.  Is the guy implying a lot of it is
spashed around or dumped directly on the ground?

While many construction practices seem to destroy the environment, this is an
old one and may be more benign than some:  foundation walls are not places
where critters are welcome.  On the other hand, they are usually well-drained
and the toxicity of any oil (reclaimed or not) COULD enter the stormwater
drainage flow.

I personally am not aware of whether there are better alternatives to motor
oil (tho I believe there are), but used motor oil sounds like its "cheapest"
and probably is solving somebody else's problem as well.



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