As Gordon Gekko says, much more information is required here. The investment properties may have a positive, neutral or negative impact on the affordability of a new mortgage, depending on the monthly repayments (which will be stress-tested by the bank) and the monthly rental income (which will be discounted by the bank). In general, the banks don't like people having total mortgages (including the new mortgage being applied for) being more than 6 times their combined incomes, but that is not a hard and fast rule. Every bank uses formulas, but they differ for every bank, and your case has enough variables that the differences between the answers you get from each bank could be significant.Does anyone know what the general bank rules are for home mortgage applications where you have some buy to let mortgages? My husband owns 4 investment properties; only 350k mortgage remains in total. We wish to upgrade from current home (in my name). There is equity available so net increase in mortgage would be 60k...are they saying no to people like us regardless of employment income situation, due to property rental risk? Or is there some kind of formula they are using?