I am installing a new lavatory in an outbuilding, and have laid the drains
to the point where I want to connect to. I intend to have the soil pipe
continue vertically past the new loo, into the roof space, and fit an air
admittance valve there. My question relates to the type of soil pipe to use.
I had intended to get some 110mm grey soil pipe for this bit, but this stuff
seems a tad expensive - I only want about 7 or 8 feet. The thing is, I have
quite a lot of brown underground 110mm pipe around and I was wondering if it
would be ok to use this and then paint it - anyone got any thoughts?