Is Zakat obligatory on the first installment paid for the purchase of a house under construction, whether for residential or rental purposes?

The money paid to the company to build a house with specific specifications is called 'Istisna' (manufacturing contract), and it is permissible. There is no zakat on this money for you because it has left your possession, and there is no zakat on the house itself because you did not intend it for trade. As for the company, it must pay zakat on the capital of the Istisna contract if a full year has passed since its acquisition, by analogy with the capital of a Salam (forward) contract. A Muslim must strive to deal with companies that avoid unlawful transactions in their dealings.