Is buying an apartment through a bank, due to the large family and cramped living conditions, considered unlawful (haram)?

It is permissible to conduct transactions with the bank if they conform to Sharia regulations, such as Murabaha or Istisna' sales. However, borrowing with interest to buy a house is not permissible except in cases of necessity. The Sharia regulations for Murabaha and Istisna' contracts have been defined in previous fatwas.