Is a bank's financing the construction of housing for employees, where the employee pays 25% of the price before taking possession and the remainder in installments over 25 years, with the bank adding a 2% profit margin on the total costs, considered usury or an investment of the bank's funds?

There is no objection to the bank building houses on its property and then selling them to employees in easy installments. It is permissible for it to take a known profit in excess of the costs. The important thing is that the price and the term are known, and that the price is not increased due to late payment. It is not permissible to deal with an interest-based bank.