Did DIY in bathroom I’d let out (5)
I believe the answer is:
tiled
'did diy in bathroom' is the definition.
(tiling is a type of DIY)
'i'd let out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'id'+'let'='idlet'
'idlet' with letters rearranged gives 'TILED'.
(Other definitions for tiled that I've seen before include "Covered eg as walls of shower area" , "Covered in ceramic slabs" , "Covered the roof" , "Like many roofs" , "Covered in pottery slabs" .)