Is the questioner obligated to pay a sum to his father, uncle, or brothers, or to his uncle's wife, for building the fourth floor on their shared land, after they have all given their approval?

The questioner must own the roof of the house through a gift so that what he builds does not enter into the inheritance of his father and uncle. If it is a gift from the father alone, without the rest of his siblings, then there must be a justification for it, such as poverty or a large family, or that he compensates his siblings with something of equivalent value.