Renovating an apartment in Manhattan is a long and time consuming process, but do not lose heart, everybody is doing it!
1. If it is a Co-op or a Condo, obtain the Alteration Agreement. This document will define everything you need to know- the insurance your Contractor will need to have, how many days you have to finish your renovation, what the elevator charges are, what damage deposit the building insists upon, the drawings to be submitted for building approval, who will sign the permit forms etc.
2. Do I need an architect? Only if you are opening walls, moving doors, adding a bathroom, moving plumbing fixtures, doing structural work etc. You do NOT need an architect for 'maintenance work' such as replacing cabinetry, appliances, flooring, painting the apartment, and other cosmetic work. If this is the case, your Contractor can directly apply to the building. Similarly plumbers and electricians can obtain their own permits for maintenance work.
3. Submit architectural drawings and specifications. The building architect/engineer will review these and comment for corrections. Then the building Co-op/Condo board will vote on it.
3. Is the building in a landmarked historic district? In which case all interior work will need to submitted to LPC (Landmarks Preservation Commission), for a perfunctory approval. That is, unless you are doing external work like replacing windows or placing AC equipment on the rooftop. Then the approval will take longer.
4. Wait for the DOB (Building Department) approval. The approval will probably come through 6 or more months after you began Step 1. The good part is that these individual timelines can move concurrently. Your architect will coordinate the process with expediter.
5. Hire a Contractor. The building management will have to approve him. It's better to go with one on the list the building maintains to save time and hassle. Your architect will coordinate your contract with him.
6. Construct, construct, construct. The architect, building architect and the DOB inspector will come by to ensure that the work is as per code and as per approved drawings. If it is a small bathroom or a kitchen job, you may not want to move out of the apartment. But do build up your resistance for noise and dust.
7. Punch lists and sign offs. The work is not considered completed until it is formally signed off by all the parties involved- the fire stopping in the corridor installed, the DOB PW3 Cost Affidavit submitted, lien waivers signed by the Sub-Contractors etc. You should hold off on the last 5-10% payment to the Contractor to cover the one-year warranty.
8. All's well that ends well. If all loose ends have been tied, you may finally enjoy your apartment. An apartment job in Manhattan takes on an average 12-18 months in my opinion, from the time you approached your building management to the time you obtained the Letter of Completion from the DOB.
And CONGRATS, you have just upped the value of your apartment, because you chose to undertake this complex process.