Princeton Historic Preservation Commission approves landscape and hardscape work for six Princeton Theological Seminary properties with conditions

The Princeton Historic Preservation Commission on Oct. 20 approved six related landscape and hardscape applications from Princeton Theological Seminary covering properties at 44 Mercer Street and 15, 17, 19, 25–27, 29 and 31 Alexander Street in the Mercer Hill Historic District.

The seminary sought permission primarily for driveway-apron and sidewalk repairs, replacement or widening of steps and landings, new railings to meet current safety codes, selective fences, and new plantings and trees. Commissioners emphasized preserving the public streetscape while allowing safety and accessibility improvements. Several approvals carried specific conditions set by the HPC.

The commission’s action followed a lengthy presentation from the applicant team led by Ryan Kennedy of Stevenson Lee and landscape architect Mara Baird, who described a campus-wide “horticultural identity” of repeated tree types and simpler turf-and-tree treatments. The seminary described recurring damage to historic bluestone at driveways and asked to replace driveway aprons with a gray-colored concrete designed to match the neighborhood while salvaging and reusing salvageable bluestone where possible.

The commission approved the applications with item-specific conditions and clarifications. Notable outcomes and conditions included:

- 44 Mercer Street: Approved with conditions that the street-facing sidewalk crossing the driveway be replaced in-kind with bluestone, the driveway apron may be replaced in colored concrete matched to the slate tone, and the seminary remove the proposed Ilex (Dragon Lady) plantings shown in the plan. The seminary may propose substitute plantings for administrative review rather than returning to the full commission. A proposal to extend the wood fence across the driveway was not approved; the commission asked the applicant to consider lower or partial screening or plant-based screening alternatives and suggested coordination with municipal engineering on sight lines and safety.

- 15–17 Alexander Street: Approved a consolidation of the bifurcated front path into a single access path, repair of existing landings and steps, and widening of an existing side walkway for improved access. The commission supported concrete for the landing/connection where site constraints make bluestone impractical. Administrative review was permitted for minor adjustments that affect an adjacent lot’s access path.

- 19 Alexander Street: The commission approved replacement of damaged steps with regularized treads and risers, new code-compliant handrails, and restoration of the driveway apron (concrete). Commissioners debated a low stone retaining wall on the front slope; the commission voted to retain and rebuild that wall as part of the approved work rather than remove it, subject to proper reconstruction and drainage considerations.

- 25–27 Alexander Street: Approved with the option to clad new steps with bluestone treads to match the street character, replacement of aprons/sidewalks where needed, and installation of consistent railings.

- 29 Alexander Street and 31 Alexander Street: Approved work that includes replacement of aprons, continued use of wood fencing where visible and aluminum fencing limited to side/rear, selective tree removals of invasive species and replacement with proposed street‑edge trees, and low‑glare pathway lighting (22‑inch bollards producing very low light levels — about 0.01 foot‑candles at 7 feet) for a shared path between 29 and 31. The panel approved wood screening in rear yards and asked the seminary to locate trees so they frame buildings rather than block primary facades.

Across the six properties the commission emphasized reuse of any salvageable bluestone, minimizing invasive species, meeting handrail and stair safety code requirements, and keeping lighting low and shielded. Commissioners also discussed the seminary’s maintenance resources and the trade-offs between historic material repair (bluestone) and longevity of concrete aprons under heavy institutional vehicle use.

Votes on individual properties varied; several applications passed by narrow margins. In multiple approvals the commission permitted administrative follow‑up for minor planting or detail adjustments so applicants could finalize details without returning for full review.

The commission recorded public comment from the Mercer Hill Historic District Association, which urged full restoration of bluestone sidewalks and recommended wood rather than aluminum fencing where visible. The seminary’s representatives responded that some existing bluestone is failing at apron locations where vehicle loads have caused damage, and the seminary needs durable aprons for institutional vehicle access; they also said they would salvage slates where feasible and were open to screening alternatives.

The commission asked staff to prepare either individual or a single consolidated resolution covering the approvals. The seminary agreed to return administratively where the commission requested only planting substitutions or small layout tweaks.

Ending: The approvals allow the seminary to proceed with coordinated repairs across multiple historic properties while the HPC’s conditions aim to protect the Mercer Hill streetscape; applicants must carry out work consistent with the commission’s direction and with any administrative follow‑ups agreed at the meeting.