What are the legitimate steps required to build a house through an Islamic bank, in light of the differing opinions regarding the dealings of Islamic banks?

Naming a bank "Islamic" does not necessarily mean that all its transactions are permissible. The criterion is the extent of its adherence to Islamic law, not the name.

To purchase a house through an Islamic bank, there are two methods: 1. Murabaha sale for a purchasing orderer: The buyer approaches the bank to specify the commodity and its specifications. The bank first buys and owns it, then sells it to the buyer in installments or with deferred payment at an increased price. This increase is permissible. 2. Qard Hasan (benevolent loan): Islamic banks rarely engage in this, as their funds are designated for investment and profit, not for lending.