Pursuant to Section 3309.5 of the New York City Building Code:
Whenever underpinning is required to preserve and protect an adjacent property from construction or excavation work, the person who causes the construction or excavation work shall, at his or her own expense, underpin the adjacent building provided such person is afforded a license in accordance with the requirements of Section 3309.2 to enter and inspect the adjoining buildings and property, and to perform such work thereon as may be necessary for such purpose. If the person who causes the construction or excavation is not afforded a license, such duty to preserve and protect the adjacent property shall devolve to the owner of the adjoining property, who shall be afforded a similar license with respect to the property where the excavation is to be made.
Pursuant to Section 1704.9.1 of the Building Code, all underpinning work must be inspected by a "special inspector."
Beginning in April 2010, the New York City Department of Buildings began enforcing a policy that requires any contractors that will be performing "earthwork" must notify the Department of Buildings 24 to 48 hours before beginning the work. In the case of underpinning, the contractor must provide the approximate date of when the underpinning operations will begin. If "earthwork", such as underpinning is cancelled, the Department of Buildings must be notified within 24 hours of the original anticipated start date. The Department of Buildings performs random audits of any "earthwork" including underpinning and any underpinning that is performed without the property prior notice to the Department of Buildings is subject to a Stop Work Order.
In January 2010 the Department of Buildings issued Bulletin 2010-001 which provided, in part, that certain buildings may be included within the "stalled site" program. In relation to underpinning, the bulletin requires:
4.4. Underpinning shall be inspected by a licensed engineer for conformance to and completeness in accordance with the approved design. All excavated underpinning piers shall be concreted and load transferred to the pier. Unless underpinning is braced by rakers or tie backs, fill shall be placed against all exposed underpinning, to prevent lateral displacement. Licensed engineer shall provide a signed and sealed report verifying current stability of underpinning and of structure that was underpinned and shall inspect periodically (minimum of once each month) to ensure sustained stability.
Contractors, engineers and architects will be familiar with New York City's from TR1 which is the Technical Report Statement of Responsibility. The underpinning special inspection can be found on the first page of the TR1 under Section 3.
All of these requirements and obligations are intended to protect the adjacent property owner from enduring damage due to the excavation operations next door. Improper or defective underpinning can cause damage ranging from small cracks and shifts leading to doors and windows that won't close property to complete and total collapse of the building. Contractors and engineers alike should make sure they are thoroughly familiar with all of the Building Code's requirements for underpinning operations in order to limit the likelihood that the building will be damaged. If damage should occur, and especially if it results in litigation, one of the first things that the attorney for the damaged property will do is find out whether the proper notices and permits were filed with the Department of Buildings. If they were not, the contractor and/or engineer could face significant liability. Of course liability may exist even if the Building Code requirements are not followed.