I’ve now reached a topic that is central to a lot of our projects but where the changes from the 2014 New York Building Code to the 2022 code are relatively small. (In other words, the reverse of Monday’s topic, where my involvement with the topic is small but the changes were large.) Even though not a lot has changed, I feel like the protection of neighboring property during construction is critical both to public safety in general and to maintaining the city’s large stock of old buildings. Two notes: first, this is a section that is wildly different from the IBC code, where it is one paragraph long, and second, I have so much to review in this section that it will continue tomorrow.
Protection of adjoining property is section 3309 in both the 2014 code and the 2022 code. There are a lot of subsections, devoted to various forms of protection. Section 3309.1 defines in general terms what needs to be protected and 3309.1.1 discusses notifying the neighbors of the planned work. The only change here was the addition of language about a class of projects with specific DEP permits about stormwater run-off. Both new and old explicitly mention protecting the neighbors from run-off and erosion.
Section 3309.3 requires examination of the neighboring buildings and properties if an agreement to enter them can be reached. We always recommend to clients who own buildings next to construction sites that they try to reach some kind of agreement to allow those examinations to take place. It is, in my opinion, better for everyone if the people performing the construction are able to perform all of the examinations required by code.
Section 3309.4 concerns earthwork and foundation construction adjacent to neighboring properties. In addition to the kinds of issues discussed in the underpinning and support of excavation portions of the code, there are complications from neighboring buildings. A building next to excavation creates, by its own weight, lateral pressure on the support of excavation as well as vertical loading in the soil. Changes in grade upward on the construction site may increase lateral soil pressure on neighboring foundations or retaining walls. Changes in grade downward may expose neighboring foundations to frost and other weathering. Both the new and old codes require a pre-construction survey of adjacent buildings when any significant excavation is taking place; the 2022 code has added an explicit requirement for geotechnical evaluation of neighboring buildings in addition to structural evaluation.
Section 3309.5 had, in the 2014 code, a requirement that people performing underpinning on their own building also underpinning adjoining foundations belonging to the neighboring buildings, assuming again that the owners were able to reach an agreement with the neighbors about access. In the 2022 code, this is extended from underpinning to include alternate forms of support such as, for example, concrete benching. It is quite easy, in theory, to create a dangerous condition by protecting your own building but not one immediately adjoining yours; this subsection is meant to address that problem.
More tomorrow on dealing with the neighbors.
Part 1: Underpinning
Part 2: Peer Review
Part 3: Support of Excavation
