Alice, I agree with the previous responses: First, check your proprietary lease to see what kind of businesses are permitted. (In our case, it's "professional" offices that don't have pedestrians from off the street walking in.) Even in the case of our medical office, the doctor's patients are prohibited from entering or waiting in the building's common areas (the doctor has a separate entrance to his office). These rules are in our proprietary lease, which all residents must follow.

Second, check the certificate of occupancy. This is on file through the city's Department of Buildings.

Third, check the zoning laws. But even if the city permits an office, that doesn't mean that your certificate of occupancy allows it. And even if the c. of o. doesn't rule out such offices, your proprietary lease may. Finally, check the house rules. While they are an extension of the proprietary lease, they may be more detailed than the p. l. and may have more information about such questions. Then again, the house rules may be silent on the topic. Still, worth a check.

Here's one of the bottom lines: If someone has a business in his/her apartment with clients coming in for meetings, who is liable if the client slips on the stairs?

I hate to always have to bring up a lawsuit, but we live in litigious times in a litigious city. The co-op must take reasonable steps to protects its investors (i.e. you & your neighbors) from avoidable expenses.

So I think you are doing the correct thing to check into the kind of offices permitted in your building.