GST rate for a single residential house for own purpose.

I am searching for answers to some of my questions on GST and saw this portal. It provides enormous information for a person in the know. However, for a layman like me I could not find the exact answer to my doubts, that are as following with a little background. I have signed a turn-key agreement with a construction company. I have purchased the land and the company is constructing the house. They will hand it over to me with complete interiors like wardrobes, kitchen etc. Now my question is on GST. They are raising bills to me with 18% GST, but without showing any details like material or labor used. My question is 1. Since this is a single residential unit, as per Notification No. 12/2017 from 28 June 2017, where it says that such units are free from GST. Is this statement still valid or has it been changed, so that such properties attract GST now? 2. If I have to pay GST, how much GST do I need to pay 5% overall as it will be a non-affordable housing or 12% or 18% 3. Should I be paying GST on a lump sum amount without any breakup given or should I expect complete breakdown of material, labor and GST charges. Request your help to answer these three questions. Thanks a lot in advance. -sudhanshu