Do I need to pull a permit if I am only changing ONE window in my house and installing an impact window? Do I need to pull a permit even though I am not changing the location or the size of the opening? We have several clients asking these questions when they are thinking about replacing one or more of their existing windows. The answer is yes, you must pull a permit if you are replacing any exterior window or door.
Impact Windows and Wind Engineering
The Florida Building Code requires you to obtain a building permit to replace an existing window for an impact window (this rule also applies if you install a non-impact window). To obtain the building permit, you will need a wind engineering report, specifying what the wind loads are for each opening in the house. The impact window or door that you are purchasing MUST have a design pressure that exceeds the wind loads calculated by the engineer. Otherwise, installing impact windows and doors is pointless.
Do Impact Windows Have Different Ratings?
The impact windows that we install in Miami must have the Miami-Dade County Notice of Acceptance, or NOA. To check impact windows ratings, you could review the NOA of the specific window or door. NOAs will have a table showing the corresponding maximum design pressures for an impact window depending on the size and glazing option used. So, it is not enough for an approved impact window to be installed in your house without checking against a wind engineering report.
Source: Carlos Paesano http://www.impactwindows.net/2010/06/impact-windows-and-bulding-permits.html