Hi I am in the process of fitting a new bathroom and have decided to move the soil pipe from inside of the house i have dug out and located the clay pipes that go to the manhole but on inspection there appears to be a hairline crack in the pipe could i reduce the new soil pipe down from 110 to 82 and insert the 82mm pipe into the clay pipe as a feed to the manhole i can cut it off after the crack and thought seal around the 82 mm pipe to stop any leakage thanks