Torn to pieces, as a roof may be (6)
I believe the answer is:
slated
'torn to pieces' is the definition.
(I've seen this before)
'a roof may be' is the wordplay.
'a roof' becomes 'slate' (slate roof is a kind of roof).
'may be' becomes 'd' (I can't explain this - if you can you should believe this answer much more).
'slate'+'d'='SLATED'
'as' acts as a link.
Can you help me to learn more?
(Other definitions for slated that I've seen before include "House roof may be - criticised" , "Reprimanded - criticised" , "as roofs may be?" , "censured" , "Unfavourably reviewed" .)