Inspect the property with representative of builder, and your own architect or civil engineeer. Do not forget to take a copy of builder's agreement and a digital camera. Record the unfinished tasks item wise, comparing with agreement, get photographs, list out all unfinished tasks, and such photographs signed by you, your expert and builder representative, and then issue a registered notice to builder and demand for occupation certificate and for completing the remaining unfinished works. Start the notice as follows.
Reg: Demand for payment of 80% amount and for occupying the flat.
Ref: Your letter dt.
As per your letter dt..., I have on ....inspected the premises with my expert engineer shri....and your representative shri...... I notice the following unfinished tasks as was agreed in agreement with you on...................., and issue this notice to complete the remaining tasks and provide occupation certificate enabling me to pay complete consideration which was remaining in my bank account, ready for disposal.
The following works remain incomplete.
(Necessary photographs, the list signed by your representative and expert engineer enclosed)
Owner of Flat No.......