If it is very hard to buy or build home in non-Muslim countries and it is also difficult to get it on rent then in such compulsion it is allowable to buy interest based mortgage house. You should buy the house with the actual price of house along with interest up to last instalment whatsoever it may be and later you should keep on paying the total price in instalments. In this case one may save himself from interest as well as may buy one’s personal home.
Allah knows Best!
Darul Uloom Deoband