Our newest client assumed there was no problem getting a building permit to put a sun deck on an existing home.
In order to save time on the project, which included a new six foot sliding glass door, the contractor installed the door prior to the building permit being applied for. Problem is the building permit will probably not be granted for the sundeck because the home is already too close to the back property line.
Make sure your contractor waits for the permit approval before beginning any work.
Now, the new patio door will open onto nothing and will need to be barricaded, probably with some nice finish trim, to prevent someone from falling out the opening to the ground nine feet below.