Bolt rear pads around material applied to walls (12)
I believe the answer is:
plasterboard
'material applied to walls' is the definition.
(type of board used when constructing walls)
'bolt rear pads around' is the wordplay.
'around' indicates an anagram.
'bolt'+'rear'+'pads'='boltrearpads'
'boltrearpads' with letters rearranged gives 'PLASTERBOARD'.
(Other definitions for plasterboard that I've seen before include "Sheet used as covering on indoor walls" , "that's going to the wall?" , "Material for making inner walls" , "Lining for interior walls" .)