Does the questioner have the right to claim the floor he built above his father's house after the latter's death and the sale of the entire house?

If the third floor was built with your own money and on top of the house's roof with the owner's permission, then it is your property, and you have the right to claim its value. This is because whoever builds on someone else's land with their permission is entitled to the value of their construction.

Since you have decided to sell the entire house, the third floor must be appraised independently, as a separate floor with no share in the land.

If the construction was done with your money, then you are entitled to it, and you have a right to the value of the third floor, which you take from the house's sale price when it is sold. The remaining amount will then be divided among the heirs according to each heir's legally prescribed share.