Belvedere Castle Geothermal Renovations

Belvedere Castle in Central Park underwent a 15-month restoration, reopening in 2019 to provide visitors with some of the best views in Manhattan. Designed by Frederick Law Olmsted and Calvert Vaux in 1867–1869, the schist and granite structure was long troubled by water leakage issues. Poor drainage and waterproofing led to damage that worsened over time and caused the Central Park Conservancy to invest in waterproofing and internal drainage repair.


After considering many options to solve for effective heating and cooling, a sustainable closed-loop geothermal system was decided upon and made possible by the Castle’s position atop Vista Rock.

The underground system was developed by drilling rigs which bored three 400-foot holes to house a piping system that uses the temperature of the earth (a consistent 50-60 degrees at that depth) to moderate the temperature of Belvedere Castle above. The geothermal loop system works as cool water travels down into the earth where it’s warmed and pumped back up to the building, on repeat, depending on the season. Inside the Castle, a heat exchanger transfers the heat into the building’s air system—heating or cooling each room. McLaren provided various engineering services the renovation possible by addressing drainage, waterproofing and climate control systems.

Geotechnical Engineering for Geothermal

Our geotechnical engineering team developed a boring plan and specifications for exploratory work which was used by the drilling contractor on the site. They conducted a review of Contractor’s detailed shop and installation drawings for approval with respect to the proposed geothermal wells, piping and trenching. McLaren then supervised the borings in the field investigation, the geothermal well installation, prepared field reports, and coordinated obtaining the boring logs, field and test results, and all laboratory testing results.

Site/Civil Engineering for Pathways + Utilities

Site plan approval documents and designs were prepared by our site/civil engineering team for an ADA compliant pedestrian pathway on the site. These documents included existing conditions of the site, proposed plans for grading and utilities, stormwater management drawing, sanitary sewer and report, as well as construction details. During this phase of the project, it was determined that a sanitary sewer discharge line was damaged and must be replaced.

McLaren engineered the utility improvements and helped make this building one of NYC’s geothermal public facilities. The team also provided civil engineering services for the design of an accessible route through the steep terrain to make this landmark accessible for all.

Pedestrian Bridge Engineering

McLaren designed and developed new pedestrian bridges in the area and inspected various existing walls on site to determine if additional support was required.