Ale not brewed in shed (4-2)
I believe the answer is:
lean-to
'shed' is the definition.
(I've seen this before)
'ale not brewed' is the wordplay.
'brewed' indicates anagramming the letters.
'ale'+'not'='alenot'
'alenot' with letters rearranged gives 'LEAN-TO'.
'in' acts as a link.
(Other definitions for lean-to that I've seen before include "Rough shelter with one-sloped roof" , "Penthouse" , "Add-on building" , "Small building resting on side of larger one" , "Outhouse" .)