What caused this?

[warren631]

I want to buy a house that has a strange problem with a tub drain basket. The basket is plastic and it looks like it has been melted with acid. What caused the disintegration of the basket? Could a drain cleaner do this? Would the PVC drain piping under the drain also be damaged? How can a home inspector do a 'non-invasive' inspection on this to determine the extent of the damage? Suggestions?
More info:
The tub is on the second floor and there is no access to inspect under the tub. If we run water into the tub to see if the drain piping is leaking by checking the first floor ceiling, it will probably leak all around the basket anyway. Click on the photo to enlarge:

Thanks for your suggestions,
Warren.

[HayZee518]

it looks like drain-o was used to unclog the drain. drain-o uses a caustic lye along with aluminum chards. when water hits the caustic - it reacts with the aluminum to form all kinds of heat, enough to melt plastic. I would suspect the shoe fitting of the tub to be destroyed and should be replaced. Access openings to the tub drain should be a part of the room architecture.

[warren631]

You must be kidding? Draino claims their product is "Safe on: All pipes and plumbing systems". It looks like someone poured battery acid down the PVC tub drain. There are also burn marks on the vinal floor in the kitchen - like the idiot also spilled some acid there.

Anyway, how to inspect non-invasivly (without cutting holes in walls and ceilings)?

Also: What is a shoe fitting?

[HayZee518]

acid won't affect plastic. it'll do a job on metals except gold. what you have there is heat, lots of heat.
I'm afraid you have NO choice but make holes.

[pushkins]

Usually there is an access hatch on the rear of the drain end of a tub, most often inside a closet in the neighboring room, if there is not the only way to determine what is actually wrong is to make one.
You can but "inspection" cover plates in a couple of different sizes to cover over the hole and allow access in future.

[inspirations]

i think HayZee518 is right................