Is it allowed to take a bank loan with interest (riba) to buy a house?
We will answer plainly. The mainstream position of the four schools of Islamic law, held across fourteen centuries, is that a loan which charges interest is riba, and riba is prohibited in the Qur’an in the strongest terms (Surah al-Baqarah, 2:275–279). A conventional mortgage, as it is normally structured, falls under this prohibition for the majority of scholars.
Honesty also requires us to tell you that some contemporary councils have allowed conventional mortgages for a first home in non-Muslim-majority countries, reasoning from necessity. That is a minority view, sincerely held by its scholars, set against a very clear textual prohibition — and you deserve to know both facts rather than a comfortable half of them.
Practically, many families in your position have used Islamic home-finance models (such as murabaha or diminishing musharakah), bought smaller or later, or rented while building a deposit. Because this is a major life decision with a fatwa dimension, please sit with a scholar you trust who can hear your full circumstances before you sign anything. We are glad to point you towards questions worth asking him.
Qur’an, Surah al-Baqarah (2:275–279), on the prohibition of riba. This answer states the majority position; the minority opinion is noted honestly rather than hidden.