NOC required from other share holders to construct house on own share

My father has ancestral property in our native place. The property had the name of his elder brother as joint family head and 3 others including my father on the 7/12 extract. The property was not divided equally and the boundaries were not marked by my grandfather. Of the four brother's only my father and his elder brother are living. The other two are deceased. All the others have sold part of their share and also constructed on it. But no one ever came to my father for signatures. Some even took loans for construction. Now I want to construct house on our share with bank loan assistance. Will I have to take signatures and noc' s from all other share holders?