On Thursday, 27 March 2025 the CTBUH Height & Data Committee held their inaugural 2025 meeting virtually, representing the first time the group has convened since last year’s CTBUH International Conference in London.

After a recap of 2024 activities, the group reviewed the new CTBUH Member Group pages, which features milestones and updates from all the CTBUH leader groups, including the Height & Data Committee. CTBUH Members can stay tuned on updates from this Committee here. Although the meeting was held virtually, this served as an opportunity to reinforce CTBUH’s international presence, with committee members representing Asia, Europe, North America, and South America.

The focus of this meeting related to the definitions for Structural Material listings within the CTBUH Tall Building Criteria. Currently, CTBUH defines the following primary structural listings: All-Concrete, All-Steel, All-Timber, Composite (such as Steel-Timber Composite or Concrete-Steel Composite) and Mixed-Structure (for distinct, stacked structural assemblies, such as Concrete Over Steel or Steel Over Concrete). Some key deliberations made in this meeting included assessing how much – or what share – of a certain material could impact a project's primary structural listings. Examples discussed included structural assemblies (façades, spires, canopies) that are self-supported, but do not impact the overall building loads; concrete-floor toppings that dampen the building and add weight but are not load-bearing; and outrigger or load-transfer floors that may use different materials and structural assemblies compared to the rest of the project. 

Further discussions evaluated the often-overlapping industry definitions “hybrid” and “composite” and if the CTBUH Tall Building Criteria should be amended or emphasized to clarify these. Also, projects that use both precast concrete and cast-in-place concrete were presented, and it was deliberated whether these should be defined as single-material or multiple-material structures.

The Committee’s discussions around structural materials are ongoing, with additional case studies and feedback from the committee continuing to be collected, some future topics are being considered for the next meeting in June. A potential topic, under consideration to be defined by this committee and tracked within the CTBUH Tall Building Database, is prefabricated and modular buildings.