Brick for building half done in Lincoln? (5)
I believe the answer is:
adobe
'brick' is the definition.
(adobe is a kind of brick)
'half done in lincoln?' is the wordplay.
'half' means to take half the letters.
'in' is an insertion indicator.
'lincoln?' becomes 'abe' (Abraham Lincoln).
'done' cut in half is 'do'.
'do' going inside 'abe' is 'ADOBE'.
'for building' acts as a link.
(Other definitions for adobe that I've seen before include "Clay dwelling" , "Sun-dried brick clay" , "Clay for mud bricks" , "Clay used for sun-dried bricks" , "house" .)