• GST to builder for construction of single family house

I have a question on GST for constructing a home for my primary stay. I gave a contract to a builder to build a house for personal use not for selling. He charges a certain amount per square foot, eg: rs2500/square feet for a total of 2800 sqft as construction cost as per the contract. Question is, Should the owner also pay 18%GST for the total construction cost to the builder in addition to the amount he charged per square foot? If yes, then what is the current actual GST charge for the construction cost as per the rule? Is there any exempt for NRI transfer? I am not purchasing the house from the builder, he is building the house as per the contract he quoted for per sqft.