A property survey plays a critical role in the commercial buy-to-let mortgage process. It provides an independent assessment of the property's condition and its market value. The survey can highlight any structural issues, maintenance needs or other problems with the property which could affect its value and rental potential. The valuation of the property also determines how much the lender is willing to loan. Lenders generally loan a certain percentage of the property's value, known as the loan-to-value ratio (LTV). Therefore, a lower valuation than expected might affect how much you can borrow.