Roof blown off house, ending in different block (5)
I believe the answer is:
ingot
'block' is the definition.
(ingot is a kind of block)
'roof blown off house ending in different' is the wordplay.
'roof blown off' means to remove the first letter (in a down clue, roof could mean the top letter ).
'house' becomes 'bingo' (I've seen this before).
'ending in' says to take the final letters.
The final letter of 'different' is 't'.
'bingo' with its first letter taken away is 'ingo'.
'ingo'+'t'='INGOT'
(Other definitions for ingot that I've seen before include "this must be cast" , "Bar of bullion, for example" , "A lump of metal like gold" , "Precious metal bar" , "Brick-shaped lump of cast metal" .)