Vintage shed erected, with familiar roofing (3-4)
I believe the answer is:
old-time
'vintage' is the definition.
(thesaurus)
'shed erected with familiar roofing' is the wordplay.
'shed' becomes 'emit ' (both can mean to give out or radiate).
'erected' says the letters should be written backwards (in a down clue, letters go up).
'with' says to put letters next to each other.
'familiar roofing' becomes 'old' (I can't justify this - if you can you should believe this answer much more).
'emit' written backwards gives 'time'.
'time' put after 'old' is 'OLD-TIME'.
(Other definitions for old-time that I've seen before include "Quaint" , "Relating to the past" , "(E.g. dancing) in ancient style" .)