Plastic to Lead/Cast iron soil fittings.

[john.bell55]

Hi, I'm Jack (54) this is my first post. I served my apprenticeship in the shipyards of Glasgow a number of years ago, but was out the trade for a while. Having never really dealt with the domestic side I have retrained with a distance learning course.
Can anybody help me regarding connecting plastic pipe to lead. I was at a job today at 100 year old house. 2 years ago a kitchen fitting company had put 40mm plastic into a 3" lead pipe and sealed it with plumbers mait. The drains blocked and the water backflowed, breaking the putty seal and as a result there is now a small paddling pool under the floor. Went to Plumbers merchants, bought Fernco type coupler with reducer, but was wrong size and next size up is too big. Tried rubber boss in the lead pipe but couldn't get it to seal properly (small drip). My next plan of action it to take the old pipe out through the wall and replace with plastic but will leave the downpipe section in cast iron. Is this too radical or can I get a coupling that would connect the plastic to lead?

 

[Dan]

Welcome to Plumbing Forum | Plumbing Advice | Plumbers Forums | A forum for plumbers advice in the UK!

Welcome to UKPlumbersForums.co.uk john.bell55. Thanks for introducing yourself.

 

[stevetheplumber]

Hi, I'm Jack (54) this is my first post. I served my apprenticeship in the shipyards of Glasgow a number of years ago, but was out the trade for a while. Having never really dealt with the domestic side I have retrained with a distance learning course.
Can anybody help me regarding connecting plastic pipe to lead. I was at a job today at 100 year old house. 2 years ago a kitchen fitting company had put 40mm plastic into a 3" lead pipe and sealed it with plumbers mait. The drains blocked and the water backflowed, breaking the putty seal and as a result there is now a small paddling pool under the floor. Went to Plumbers merchants, bought Fernco type coupler with reducer, but was wrong size and next size up is too big. Tried rubber boss in the lead pipe but couldn't get it to seal properly (small drip). My next plan of action it to take the old pipe out through the wall and replace with plastic but will leave the downpipe section in cast iron. Is this too radical or can I get a coupling that would connect the plastic to lead?

lead pipe can be dressed smaller or larger to fit the fernco but best to remove lead right through and replace burn the lead out of the cast and make the plastic in with some paper and cement joint always best to have a cleaning eye where it goes into stack

 

[john.bell55]

Thanks Steve, as the lead is underneath the sink and passes through the wall access to dress it would be difficult. I plan remove the lead back to the outside and replace the cast elbow with a plastic one. The cast pipe is a 2 1/2 " O/D and is connected directly to the main sewer of the property and serves only the kitchen sink, and is not vented. Being a bungalow this at ground level and access is easy.