"Peter Jason" wrote in
:

Thanks. I do know about the Clorox method and the other which is
the application of C12 quaternary compound (supposed to leave a
retardant film on the slate surface), but the only reason I have
not tried these is because I fear my gutters corroding. But I
will try the Clorox method after the Roundup (applied yesterday)
works or not works. ncidently I have just had my drains routed
for roots (there were plenty) and the plumber said that the
terra-cotta drains were cracked and that I should flush some
copper salts down the toilet to dissuade future root infiltration.
Before the plumber arrived and while the drain was still backed
up I emptied some Roundup into it in the hope this might kill a
large length of root. Anyway, now I have a bag of copper sulfate
next to the toilet and I throw about half a kilo down the bowl
twice a week followed by a half flush.

Do you know if this sort of thing works well?


You probably don't need to use that much copper sulfate at a time,
and I would suggest checking with your local laws about dumping
Roundup down the drains. Here in the US, it is illegal to do that.

Sean