House part (4)
'house part' is the definition.
(I know that house has part or parts roof)
This is all the clue.
(Other definitions for roof that I've seen before include "Topmost part" , "Eg, mansard, gambrel" , "Top of building, mouth, world" , "Protective covering on top" , "Upper covering" .)
(Other definitions for living room that I've seen before include "Area in home for relaxation" , "Home space" .)