What materials is getting used on the wall and ceiling on this area?

The identical materials may be seen on each the inside and exteriors of the house, anybody know what it’s?

https://preview.redd.it/3wayba3adh0d1.png?width=1851&format=png&auto=webp&s=8f8b58d60ce00eea076a86d34fce25467abdd7bf