Hello! The time it takes for the city to review and approve building permits can vary depending on a number of factors, such as the complexity of the project, the workload of the city’s building department, and the completeness of the application. However, in Denver, the city’s website states that the review process for a standard commercial building permit takes approximately 20 business days. It’s always a good idea to check with your local building department to get a more accurate estimate based on the specifics of your project. Good luck with your office fitup!