This is the code:
A building permit is not required for one story, detached accessory structures used as tool or storage sheds, play houses and buildings of similar use provided the floor area, which do not exceed 120 square feet.
Garages, garage conversions, room additions, carports, patio covers, accessory structures and similar improvements which are attached to your home or which exceed the allowable area, require the issuance of a building permit.
Plans for such improvements must be submitted for approval to the Building and Safety Division prior to the issuance of a permit. Permits for smaller projects, which are less complicated, may be approved over the counter provided adequate information is shown on the plans.
It says nothing about attaching it (except to the house)
and here are the pictures:
http://img417.imageshack.us/img417/5264/dsc00730gs0.jpg (http://imageshack.us)
http://img244.imageshack.us/img244/714/dsc00731qv8.jpg (http://imageshack.us)