Their are several “loopholes” which make it halal.
One is one they refer to as Inqath mal al kafir- this works when the financial institution is a non-Muslim one.
If they are offering you money, you are allowed to take it, not with the intention of loan. Then later they ask you to pay it back, with some fees you do so in order to save your house. But the initial taking of the money was not with the intention of a loan, even though technically it is a loan.
Another is to consider the interest as fees given to the bank, they did paperwork, etc for your needs to be met. That extra you are giving is to pay for those fees.
Another would be to not consider it a loan, you are buying a house, the money goes directly from the bank to the house owner. So technically you are agreeing to purchase the house from the bank at a more expensive price.