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E-M:/ Oil on Foundations

Enviro-Mich message from anne.woiwode@sfsierra.sierraclub.org


Thanks already for the three responses I got within a couple of hours -- FYI,
here is what I have learned.  I guess the lack of clear guidance and
possibility for contamination is the concern here!   Anne Woiwode

The forms are special plywood for basements and the contractors spray them on
what will be the inside before putting them up.  The forms can then be taken
apart after the cement cures.  Otherwise, the plywood needs to be replaced
more frequently.  The forms are not dripping and after taking the forms off
the inside of our basement when it was poured, there was no evidence of it nor
odor on the walls.  Whatever amount there was had been soaked into the cement.
I doubt that there is much if any env impact from the process.  On the other
hand, if a contractor uses to excess and as an excuse to get rid of motor oil
that's another matter.


Yes, we recently had a concrete slab poured and the builder used a little fuel
oil brushed onto the 2x12 boards that "form" the shape of the concrete so that
it would pull away from the thickened concrete cleanly. I was surprised and
asked about it and was told "thats how it's done". I didnt think much of it
since they did apply the oil in very small amounts (100-200mls?) with a brush
directly to the porous wood. I figured if it's applied to the wood as
prudently as possible, most loss and need for re-oiling on subsequent job
sites would be due to evaporation. If it's being sloshed around by the tens of
gallons, and used motor oil no less, that seems like a very legitimate


This is the scoop I got from a small-time Lansing-area builder (who doubles as
my husband):

A tar-like substance is put on block and poured walls before they backfill.
Some of that will settle at the bottom of the foundation between the footing
and the block wall, which is a natural, gravity-driven, outcome.

If they have some left over, they "take it to the next job site."  Which is
what he said between laughs.  (Actually, the remaining tar and the bucket
usually end up as part of the backfill.  Builders bury a LOT of waste
on-site.) He added that the new technology is to spray the tar-like stuff on,
which may make it easier to reuse the leftover.

Hope this helps.

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