For most people, purchasing a property is one of the largest investments you are likely to make in your lifetime.
Most purchasers rely upon the valuation survey which primarily ensures that any loan is safe.
However, this is often a superficial inspection of the property and does not identify all defects that are currently apparently, or those items which are likely to require investment in the short to medium term.
A full building survey (level 3 survey) is a detailed survey of the property both internally and externally which both describes the construction of the building, and identifies any apparent problems, or defects likely to occur and where investment will be required.