Weatherboard??

[stevedam850]

Taking down a molded drywall in my room and noticed some other kind of board.
It’s called intermediate weatherboard

I added a picture.
What type of replacement do I need for this? I can’t find anything at the big box stores called weatherboard.
Thanks

 

[Snoonyb]

Looks like an asphalt impregnated fiber board and was probably used as a vapor barrier, which there are modern day replacements for.