Cast Iron soil pipe

[ashleyp]

I've got a leak coming from the saddle boss taking the PVC plumbing into a cast iron soil pipe. What is the best material to use to seal it from the outside - it looks like there is silicone there currently and some has peeled away.

Thanks, Ash.

 

[Hugh Jaleak]

Either more silicone, denso tape (filthy stuff but might work), or ditch the current boss for a 'Timesaver' boss (or other mechanical type that uses a rubber gasket to make the joint). Plastic to cast. sealed with silicone is never going to be entirely successful....

 

[Madrab]

If it was me, given the job conditions, rather than using silicone that needs a really clean, dry surface to take well, I would use a highly flexible, high grab, wet adhesive sealant, like wet grab or similar to give the best chance of minimising failure from movement and giving the best grab. Alternatively a permanently wet mastic, say something butyl based, basically it doesn't ever fully harden, stays slightly wet under the thick skin it creates.