Column I covered in pargeting (8)
I believe the answer is:
pilaster
'column' is the definition.
(I know that pilaster is a type of column)
'i covered in pargeting' is the wordplay.
'covered in' is an insertion indicator.
'pargeting' becomes 'plaster' (pargeting is a type of plaster).
'i' inserted within 'plaster' is 'PILASTER'.
(Other definitions for pilaster that I've seen before include "Rectangular column support projecting slightly from a wall" , "Decorative column standing out from the fa?ade of a building" , "Rectangular column projected from wall" , "Piles tar into a form of column" , "Square column" .)