A let to buy mortgage or http://www.mortgage-glossary.info/buy-to-let.html buy to let mortgage (which ever takes your fancy) will allow you to buy another property with the intention of letting it out to other persons. This is seen as an investment. If you want to move out of your current property and are unable to sell your existing house or you have what is known as negative equity using a buy to let mortgage will enable you to buy a new house and use your existing property for renting out.