1. If your grandmother had deposited the title deed standing in her name with the lending Bank creating security interest on it, the Bank will not return the said title deed to any person other than the mortgagor.
2. So if is highly unlikely that the said Bank has returned the original title deed to your Uncle.
3.Enquire the exact fact from the Bank through FTI mode.
4. If you find that your grandmother hasn't registered any gift deed in favor of your said Uncle.,you can file a partition suit claiming your share of the said property.
5. Simultaneously, you can also file a petition praying for an order restraining your uncle to carry on his renovation/construction work till the suit is disposed off.