Difference in the role of Cenaculum and Triclinum

Question

Why Romans had both, Cenaculum and Triclinum, as dinning rooms?

What was the difference, and why Cenaculum was upstairs? What was the benefit to have a dining room in the attic.

I know what is a triclinum, as I read articles about it. Apart form the fact to be a room and a piece of furniture allowing to eat in a lying position, it seems like a regular dinning room.

On the other hand, the dictionaries define Cenaculum as "attic" or "upstairs dinning room".
So, why upstairs? If there alreay had a triclinum, why a Cenaculum upstairs?

Answer 1

Höcker, Christoph (Kissing), “Cenaculum”, in: Brill’s New Pauly, says the following about cenaculum:

"originally the dining room on the upper floor of the Roman house. From time to time the term cenaculum includes the entire upper floor (Varro, Ling. 5,162; Fest. 54,6); the rooms described as cenacula were for accommodating guests of an inferior rank or slaves. They could also be the object of a lease; cenaculum became in this context synonymous with shabby housing."

Some examples:

consul socrum rogat ut aliquam partem aedium vacuam faceret, quo Hispala immigraret. cenaculum super aedes datum est, scalis ferentibus in publicum obseratis, aditu in aedes verso. (Livy)

Circum cavum aedium erat unius cuiusque rei utilitatis causa parietibus dissepta: ubi quid conditum esse volebant, a celando cellam appellarunt; penariam ubi penus; ubi cubabant cubiculum; ubi cenabant cenaculum vocitabant, ut etiam nunc Lanuvi apud aedem Iunonis et in cetero Latio ac Faleris et Cordubae dicuntur. Posteaquam in superiore parte cenitare coeperunt, superioris domus universa cenacula dicta; posteaquam ubi cenabant plura facere coeperunt, ut in castris ab hieme hiberna [..] (Varro)