The Statue of Liberty Museum provides a context for the nation’s ideal of liberty, while protecting precious artifacts, including the original torch.

To maintain interior humidity and conserve energy, the building envelope was insulated from penetrating support structures using structural thermal break technology.

The 26,000 square-foot Statue of Liberty Museum located on Liberty Island was designed to complement the experience of visitors to this important UNESCO heritage site by illustrating the sculpture’s historical significance and method of construction.

Opened in 2019, the award-winning LEED Gold building features an expansive green roof with native plants that capture and filter storm water, while creating a visual continuation of the island’s gardens. The asymmetrical structure is built of precast concrete with design accents in steel, granite, bronze and copper-zinc alloy, mirroring the materials used in building the statue and Fort Wood. Floor-to-ceiling windows of bird-friendly glass afford expansive views of the statue and New York Harbor.

The building’s energy-saving features include a high-performance building envelope, an advanced LED lighting system with occupancy and vacancy sensors, an energy efficient HVAC system with demand-control ventilation, and high-performance chillers. Collectively, these measures are projected to provide annual energy savings of 33%.

To minimize thermal bridging between the museum's interior floor slab and exterior extension slab at the rear of the building, concrete-to-concrete structural thermal breaks supplied by Schöck North America were installed at the building envelope, reducing heat energy loss by up to 90% at the penetration.

Mitigating thermal bridging in concrete construction 

Thermal bridging is a major risk at any point where structural concrete penetrates the building envelope––such as at parapets, canopies and balconies––and conducts heat away from the warm interior environment during winter months. In addition to wasting energy, these chilled penetrations can form condensation in cavities on the warm interior side of the structure, leading to mold growth that may take years to become visible on interior walls and ceilings. This is particularly relevant for museums housing fragile, humidity-sensitive collections.

Portion of original plans showing location of structural thermal breaks

For the Statue of Liberty Museum, the design team specified Isokorb® concrete-to-concrete structural thermal breaks. Designed for cantilevered concrete slabs, these load-bearing modules consist of stainless steel rebar that protrudes from opposite sides of a rigid insulation block with fire plates top and bottom. The resulting assembly resists uplift as well as gravity forces and offers a fire rating of up to 120 minutes.

The insulation material used in Isokorb® thermal breaks conducts 98%bless heat energy than concrete, while the stainless steel rebar conducts two-thirds less heat energy than carbon steel rebar, reducing overall heat loss at the connection by up to 90%. The use of stainless steel rebar close to the insulation element used with carbon steel for the remainder reduces product cost while also improving corrosion resistance and longevity of the module. 

The modules are installed in line with the building envelope insulation, with protruding rebar tied into rebar cages on both sides prior to pouring the concrete. Concrete can be poured on both sides of the envelope simultaneously, or only on the interior side up to the thermal break modules which can serve as a pour stop, allowing subsequent mechanical and electrical operations in exterior cages.

For construction in areas of seismic activity, specialized modules are available to resist horizontal forces.

Concrete-to-concrete structural thermal breaks are available configured for balconies, parapets and slab edges, and can accommodate balcony step-downs, in-slab ducts, post-tensioned construction, waterproofing membranes and other project details. The modules can also be installed in precast concrete elements at the factory.

Mitigating thermal bridging in steel construction

Thermal bridging also occurs where steel balconies, canopies, rooftop equipment and other steel structures penetrate the insulated building envelope, dissipating heat energy from the building’s heated interior into cold exterior environments at high rates―unless mitigated by a thermal break.

Structural thermal breaks for steel construction are load-bearing insulation components designed to transfer loads from an external structural element to a supporting structural element, while thermally breaking the two structures inline with the insulated envelope. 

These modules consist of insulating material placed between stainless steel plates on each face and fastened with two stainless steel bolts. The plates and bolts impart the module with the requisite stiffness to transfer axial, shear and bending stresses, while minimizing or eliminating the risk of mold by preventing interior surfaces from cooling and forming condensation.

The stainless steel structural elements are approximately one-third as conductive as carbon steel and they resist corrosion. The insulating material between the plates minimizes the conductive surface area, reducing heat transfer by up to85% relative to a continuous steel beam.

Concrete-to-steel structural thermal breaks are also available for steel cantilever attachments, such as balcony supports, canopies and sunscreens connecting to concrete elements.

Outcomes of insulating concrete and steel penetrations

Sustainability standards in today’s buildings cannot be achieved through incremental improvements in conventional energy-saving measures, as building envelopes cannot be significantly more airtight, insulation much thicker or windows quintuple-glazed. Instead, architects and structural engineers of the world's greenest high rises such as the Cornell Residential Tower in New York City, the National Museum of African American History & Culture in Washington D.C. and the Tower at PNC Plaza in Pittsburgh have taken a more aggressive approach, finding all-new ways to improve energy savings at structural penetrations through the building envelope, benefiting owners and developers on several fronts:

Energy efficiency

Compared to non-insulated connections, a structural thermal break can reduce thermal conductivity, energy costs and associated carbon emissions by 50 to 90%at the penetration under standard load-bearing situations.

Interior comfort

By reducing heat loss, structural thermal breaks can increase the warmth of interior floors opposite balconies and eyebrows, canopies and other extensions of interior floors by up to 34oF.

Prevention of condensation, mold 

By preventing the interior side of the penetration from becoming chilled and reaching dew point, structural thermal breaks can prevent condensation and mold formation while protecting the developer/owner from associated mold remediation and liability.

LEED points

By contributing to lower energy consumption and CO2 emissions, structural thermal breaks assist building owners and developers in meeting LEED, Passive House and other sustainability certifications.

Real estate value

Buildings with low operating, maintenance and liability costs command higher sale prices, incentivizing developers to preempt thermal bridging during the design stage.

New technologies preserve the past, look to the future

While museums are purpose-built to protect the past, all construction projects are under pressure to protect the future through sustainable design for new as well as repurposed, adapted reuse or revitalized buildings. The latest technologies for fenestration, wall systems, structural thermal breaks and other building components will help provide energy efficient, low consumption buildings that meet today’s more stringent building energy codes.