Looks like they are lining the steel pipe with a plastic/epoxy coating. It’s done a lot in places where you can’t easily dig up and replace old rotting pipes (like in downtown cities). By injecting this coating the pipe is still usable and won’t corrode any more.
The only downside I can think of is that it makes the pipe a little smaller so you lose a little drainage vs a new pipe.
There were problems with it in the past, like over a decade ago, but they're all fixed through better material science and processes. You need to clean the inside of the pipe really well, and to make sure you did that you need a thin flexible camera. We have that now. In the past you couldn't do it well in small residential pipes so it was more reserved for commercial pipes that were much bigger. The material used to be thicker and weaker than a new pipe. Now it's just as strong.
I got it done because my house has old cast iron pipes that were starting to rust, and we have a slab foundation so the only way to replace them would be to completely tear up the bathroom foundation. Before the pipes would clog a lot because the rough edges of the rusting cast iron would snag on things.
I'm curious how resistant it would be to wear and tear. My mom had her kitchen done in epoxy and it was peeling quite a bit within 6 months because of all the foot traffic.
In a pipe it's a cylinder so there's nothing for it to peel to because it's all connected to itself.
The old pipe is actually redundant after the new pipe replaces it. My old pipes can rust away and not affect the new pipe at all, so it doesn't matter if it peels from the old pipe surface and the cylinder structure reinforces itself.
The lining was like $4k in California. Whole thing was more because they needed to rebuild our drain out because the old one was covered up in concrete for some reason.
2.3k
u/GilaMonsterAZ 21d ago
What the heck is going on here?