Buy to let mortgages are for investment properties. Generally buy to let mortgages are available up to 75% of the property value. Your expected rental income must exceed your mortgage repayments by a certain percentage. For example you mortgage lender may require a rental income of 130% of your monthly mortgage payments. Your lender will also want to establish whether the property you are buying is a good long term investment. You will also need to bear in mind when considering buy to let mortgage additional costs such as insurance premiums for building and contents, rental and legal expenses cover, letting agents commission, the cost of keeping the property in good condition, service charges and ground rent if the property is leasehold.