Metal roof of Tudor home (3)
I believe the answer is:
tin
'metal' is the definition.
(I know that tin is a type of metal)
'roof of tudor home' is the wordplay.
'roof of' indicates taking the first letters (in a down clue, the top letter).
'home' becomes 'in' ('he's home' can mean 'he's in').
The initial letter of 'tudor' is 't'.
't'+'in'='TIN'
(Other definitions for tin that I've seen before include "A silvery-white metal, symbol Sn" , "Kind of metal often used as food container" , "loaf of bread" , "Silvery-white metallic element" , "Silvery white metal" .)