Gst on works contracts.

We have two types of contractors. 1. Workers are supplied on man days + 7% commission basis. Contractor raise bill on monthly basis and we paid. 2. Another contractor is paid on per kg. (piece rate basis) manufacturing basis. Our question is whether we are liable to pay GST on both type of Contractor? Both contractor's turn over is more than 20 lakh. Please specify gst rate on above both.