All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Buying these apartments in this manner is included in the Istisnaa'(manufacture) contract. The scholars of Fiqh provided different views regarding the permissibility of this contract. In its seventh session in Jeddah, the Islamic Fiqh Academy permitted such a contract when two conditions are fulfilled:
First: Clearly stating the nature, type, amount and required specifications of the product to be manufactured.
Second: Specifying the time limit.
It also states that, in the Istisnaa’ contract, payment may be deferred in full or scheduled according to pre-determined installments and specific due dates. The Istisnaa’ contract may include a penalty clause if so agreed by the two contracting parties, subject to the case of force majeure.
Having stated this, if this apartment is bought according to the aforementioned conditions where all descriptions are determined, beyond ignorance that leads to dispute, and there is no other violation of Sharee‘ah, such as consuming Riba or dealing in it, then it is permissible to buy it.
Allaah Knows best.