Coming from Ghent, Brussels or Antwerp:
Take the E40 motorway towards Ostend to junction 8. Then take the E403 motorway to junction 9 (Lichtervelde). Turn right and continue to the roundabout. Turn left and continue for about 3 km to the next roundabout. Continue straight ahead for about 200 m until you reach Sadef on your right.
Coming from Lille/Kortrijk: