Judge in Pennsylvania with second-class house (6)
I believe the answer is:
prefab
'house' is the definition.
(I have seen 'Temporary house ' mean 'prefab' so perhaps 'house' could also mean 'prefab')
'judge in pennsylvania with second-class' is the wordplay.
'judge' becomes 'ref'.
'in' means one lot of letters goes inside another.
'pennsylvania' becomes 'pa'.
'with' says to put letters next to each other.
'second class' becomes 'b'.
'ref' going within 'pa' is 'prefa'.
'prefa'+'b'='PREFAB'
(Other definitions for prefab that I've seen before include "Ready-made building" , "Building manufactured by assembling pieces" , "Building up, quickly" , "Building ready made in sections" , "small postwar house" .)