Is zakat obligatory on money saved to build a house, and to which of the poor relatives (brothers and sisters) should it be given?

If the saved money reaches the nisab (minimum threshold) and a hawl (full lunar year) passes over it, then zakat becomes obligatory on it, even if it is for the purpose mentioned. Paying zakat to deserving siblings is more preferable than paying it to others, because it is both charity (sadaqah) and maintaining kinship ties (silah). It should be given to the most needy among them. The one who is eligible for zakat is he who does not find what suffices him in terms of essential food, clothing, and shelter for himself and those he supports.