Mansion I refurbished a problem after retiring? (8)
I believe the answer is:
insomnia
'a problem after retiring?' is the definition.
(retire can mean to go to bed)
'mansion i refurbished' is the wordplay.
'refurbished' indicates anagramming the letters.
'mansion'+'i'='mansioni'
'mansioni' is an anagram of 'INSOMNIA'.
(Other definitions for insomnia that I've seen before include "Inability to drop off" , "Condition affecting sleep" , "Habitual sleeplessness" , "Sleep disorder" , "problem at night" .)