I am looking for information on any regulations related to building a
roof deck on top of a 4 unit condo building in Chicago.  We have
private roof rights to the roof and access via staircase that opens
onto the roof.  The building sits on a standard size city lot and is
masonry construction.  This deck will be on the roof and not connected
to the back of the building.  Half of the roof would be decked and be
approximately 30 ft long by 20 ft wide.  It will be flat with no
stairs.  The only additional structure on the roof deck may be a
pergola.  I have searched the city of chicago websites and found info
in the section on porch and deck restrictions, but this info did not
seem relevant to roof decks.  I have also searched in general and
found very little
info on constructing a deck on the roof of a condo building.  Please
do not provide info on green roofs or deck construction on larger
buildings.

Information needed includes any special regulations, permits required,
etc.  This would include things like appropriate material and the need
for a railing around the edges.

Additional info that would be helpful includes any information on
methods of placing a roof on a flat deck which utilizes wood decking
and contractors or builders able to or even specializing in building
roof decks in the Chicago area.  An example of someone in NY that I
would consider as a specialist in this area can be found at
http://www.panix.com/~brooklyn/urban.html.  I am looking for something
similar in Chicago.  This additional info will be rewarded with a tip.

You might want to call these people:

://www.google.com/local?hl=en&lr=&client=firefox-a&rls=org.mozilla:en-US:official&q=just-decks&near=Chicago,+IL&sa=X&oi=localr

I am in a similar situation to you and am looking to construct a
similar size deck on my privately owned roof.  Did you ever receive
any good feedback re: your questions?

I had a deck company over this morning and they informed me that my
roof deck needs to support 100 lbs. / sq ft and well as the stair case
going up to it.

This equates into huge $$$! 

Let me know.

SPR

I built a rooftop deck the rear of my home.  The contractor had to
tear off a lot of the existing roof and add to it to meet code
requirements. It must be as strong as an interior floor to pass code.