My building allows roof access, and we even have a some what improvised "garden" up there. But in all the time I have spent up there, I have never noticed anyone on any of the ajoining roofs, which makes me think we are in the minority in allowing access. I suspect this is a building by building issue, and I also suspect that co-op's probably allow more access than rental buildings. If your building is a co-op, I'd suggest discussing this at the next board meeting. My building allows roof access, and we even have a some what improvised "garden" up there. But in all the time I have spent up there, I have never noticed anyone on any of the adjoining roofs, which makes me think we are in the minority in allowing access. I suspect this is a building by building issue, and I also suspect that co-op's probably allow more access than rental buildings. If your building is a co-op, I'd suggest discussing this at the next board meeting. If there is an explicit rule against access, you can always propose changing it. As the neighborhood gets younger, some of the old, strict rules in buildings are being relaxed. Sometimes this is good, sometimes bad. I will say though that in the eight years I have lived in this building with full access to the roof, we have NEVER had a single issue with security because of that access.