Joist Overhang

I am building a small deck (10sq/m) around a concrete slab. On one side I was going to place a bearer near the house foundations but have found some piping that cannot be moved. The bearer will need to be 550mm from house meaning a 500mm overhang of the 100x50 f17 joists, Section is 1500mm wide. Is this o/hang too much or should I use a ledger board to concrete block foundation. Had heard that using a ledger board can introduce moisture to foundations so was going to keep deck separated from house!