Okay so I’m working on my basement project (thanks for everyone’s help in all my other threads!!) and I’m roughing in this basement toilet. I used the 3”x4” closet bend as Packy instructed, and now I need to come about 18” vertical. After the concrete is replaced, I’ll cut it flush and glue the flange inside this 4” pipe.

Anyway, I went to my big orange box store yesterday to buy one of those 2’ lengths of pvc for this. I don’t need 4” anywhere else so I didn’t want to buy a 10’ length and just throw it away.

When I got home I realized it’s “foam core” pvc. All my other pvc is normal solid pvc.

Should I use this foam core or do I need solid for this? I searched online and read a lot of horror stories, in particular, foam core for a toilet riser and also foam core underground.

What should I do? Thanks in advance.

i would use it..
from the internet.
no water above 140deg F. and no pressure either.
neither of these are present in a toilet drain.
"DWV parts look very similar to standard white schedule 40 PVC pipe and fittings. The only real difference is that DWV PVC is not made to handle pressurized uses like schedule 40 parts are. ... Drain, waste, and vent applications use gravity to create the flow of water and waste through the pipe line"