Putting up a new wall

There are companies whos sole purpose is to build temporary walls for people looking to add a room by adding a wall (just google 'pressure walls'). To add a permanent wall would be roughly the same thing.

It wouldn't be bad to review your alteration agreement (your managing agent will have a copy) just to be sure, but 99% of the time it shouldn't be a problem.

I can tell you from my experience, that whenever you take down or put up a wall, you have to get a DOB permit, which means hiring an architect. I was told that the city is enforcing this existing law much more strictly now.

Temporary walls are a different story, as well as walls that are purely cosmetic. If cost is a concern, a temporary wall is the way to go.

You also may be able to put a wall up without a permit if the original wall was taken down without a permit (illegally).

I would talk to your super.