Building a cellar takes 20 blocks, 5 boards, 1 cast iron and it makes 16 movable rocks that act like the rocks found in nature. They can be chipped and they can be made into runestones and the likes.
On the downside we now have 16 rocks at our not so big camp. And we are digging another cellar.
No, you can not have more than one, they lead into the same one. Through the same staircase, mysteriously.
EDIT: Building more than one seems to bug it quite severely though. We can't exit any longer. I could initally but no longer and never my compatriot. Had to relog.
Oh. I didn't see that there, and I'd already looked there, too. I guess I have to put off the making of curd, since I don't have the facilities set up for making vinegar yet...
And here I was hoping I'd have quick access to a non-forest-meat source of STR.