Reportedly, I ascend ugly building (7)
I believe the answer is:
eyesore
'ugly building' is the definition.
(I've seen this before)
'reportedly i ascend' is the wordplay.
'reportedly' shows a homophone (sound like).
'ascend' becomes 'sore' (I am not sure about this - if you are sure you should believe this answer much more).
'i' sounds like 'eye'.
'eye'+'sore'='EYESORE'
(Other definitions for eyesore that I've seen before include "Monstrosity" , "A monstrous carbuncle" , "Unpleasant sight" , "it looks bad" , "Something ugly and offensive" .)