1992 House - Oxidation Sediment from Drain

[jwarr]

Hey all,

Helping a friend out with what I was hoping was a simple clog in his shower stall. Stall is on the 2nd floor master bath suite. All other fixtures are draining well. The shower drains but very slowly. After plunging and snaking we had what appears to be oxidation sediment. The initial drain is 1 1/2" pvc but it appears to transition to some type of iron pipe and then back to pvc. We are probably going to cut out the ceiling below to get access but can anyone think of a reason that a house build in 1992 would have a drain that would start pvc, transition to iron, and transition back to pvc??

Thanks in advance.

 

[jwarr]

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[Reach4]

but can anyone think of a reason that a house build in 1992 would have a drain that would start pvc, transition to iron, and transition back to pvc??

Cast iron is quieter, so less water-running sound.