What is a Pre-Approval?
Pre-approval does not mean your finance has been approved, You have not met your finance clause in your Land contract with a pre-approval.
Another name for pre-approval is a conditional approval. Generally it means that the bank has assessed your submitted application and is happy to proceed providing you meet a number of conditions.
Generally they are that a suitable valuation is conducted on the property requiring a full set of building contracts and a full offer and acceptance and any special conditions that they feel they need further information on.
Perhaps a closure letter for a credit card you have stated as being closed in the application etc… The ultimate green light from the finance provider is the issue of a formal finance approval or unconditional approval.