If you begin construction without the required permit(s), a "Stop Work Order" will immediately be issued by an Inspector. You will be required to apply for the permit(s) and pay additional fees (twice the amount of the original fee). After the permit has been properly issued, you will then be required to uncover any work which has been covered so that it may be inspected prior to the release of the "Stop Work Order," or the building official may allow an engineer or architect to inspect and take responsibility for the work.
He would then have to write a letter to the building department accepting responsibility for the work and assuring the work complies with the code. In some cases, regulations or codes may not permit the type of construction that has been done. In this case, you may be required to replace or restore the area to its original condition prior to your construction.