Were perhaps the toilets or toilet retrofitted, IE the breathing at the low
level is very much older than the new one? Are we sure they are on the same
sewer? If it is, personally, I'd put a bung in it, but there you go!
Brian

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"Farmer Giles" wrote in message
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On 22/06/2019 14:58, George Miles wrote:
From the manhole of the victorian sewer I have one pipe going up the
outside of the house, with a branch from the upstairs toilet, then up to
the top where it breathes.

But there's another pipe going up about five feet to a grill. This
smells. But what's the point of it if the sewer can breathe through the
pipe at the roof?

Can I block it with cement?

Or could there be a reason for it?

George


Put an air admittance valve on it.