Flat excavations (4)
I believe the answer is:
digs
This clue is a double definition.
'flat' is the first definition.
(thesaurus)
'excavations' is the second definition.
('dig' can be a synonym of 'excavation')
(Other definitions for digs that I've seen before include "Excavates; lodgings" , "Lodgings (inf)" , "Lodgings - snide remarks" , "Accommodation - makes a hole" , "Appreciates - accommodation" .)