Strong chalet? It is rebuilt (8)
I believe the answer is:
athletic
'strong' is the definition.
(I've seen this before)
'chalet? it is rebuilt' is the wordplay.
'is rebuilt' indicates anagramming the letters.
'chalet'+'it'='chaletit'
'chaletit' is an anagram of 'ATHLETIC'.
(Other definitions for athletic that I've seen before include "Wigan, for example" , "Lithe cat (anag.)" , "Team" , "See 12" , "Sporty, able-bodied" .)