New York City Commercial Leasing provides information on leasing commercial space & commercial real estate in New York City.

When you have found space that works for you, and the size and condition have been ascertained to your satisfaction, you need to consider what kinds of alterations may be required for you to use the space in the manner that you contemplate. (See:
Other Consultants for Tenant) In order to perform any alterations to the space you will need various consents and approvals, not only from your landlord, but from the relevant governmental agencies having jurisdiction over the space based on the types of work that you need to be performed. You will need your licensed architect and engineer to inspect and examine the space and inform you as to the nature and complexity of work that is needed for the space to meet your expectations -- as well as the price to be paid for that work. Often, depending on the type of the deal offered by the landlord, the landlord will contribute all or a part of the work. This is known as "Landlord's Work". Landlord's Work may take the form of direct monetary allowances or a Landlord's Work Letter. There are significant potential tax implications which relate to Landlord's Work, and here's where your accountant and lawyer can play an important role. Any work agreed to be performed by the landlord must be shown in detailed plans and specifications, which should be added to the lease as "exhibits." There is also work that landlord will not agree to do; this is "Tenant's Work." It is important to clarify who is doing what work, and to make sure that the timing and other logistical considerations are in place so that Landlord's Work and Tenant's Work may be coordinated. The importance of the role of the licensed engineer and architect cannot be overemphasized. The scope and basic components of all of this work must be in place before any deal letter or letter of intent is signed or issued, and the details of all of this work must be in place before the lease is signed.