The David Rubenstein Treehouse, opened in fall 2025, marks a milestone in Harvard University’s architectural and sustainability ambitions. Located in Boston’s Allston neighborhood and part of Harvard’s new Enterprise Research Campus, the Rubenstein Treehouse serves as Harvard’s first mass timber building and university-wide conference center. Designed by Studio Gang, the Treehouse reinterprets the typology of a conference center as an open, community-oriented space that fosters exchange and connection - both within the university and with the surrounding neighborhood.

Glulam Structure with Block-Glued Timber Engineering

A key element of the building’s structure is its expressive use of glued laminated timber (glulam), supplied by the HASSLACHER group. Approximately 750 m³ of spruce glulam were delivered for the project, most of it block-glued glulam and produced at the group’s site in Hermagor (HASSLACHER Holzbausysteme GmbH).
The block‑glued glulam beams are composite timber elements in which several glulam components are bonded together using a gap‑filling adhesive and hydraulic pressure to create robust, high‑performance structural units. This construction method is particularly relevant in multi‑storey mass timber buildings, as it enables the safe and efficient transfer of high vertical loads — making it ideal for public buildings and institutional architecture where architectural ambition must be combined with high structural performance.

Design and Function of the Timber Conference Center

The Rubenstein Treehouse is designed to evoke the experience of ascending into a treehouse. A central staircase, illuminated by skylights, wraps around two freestanding elevators and connects flexible meeting and event spaces across multiple levels. The visible timber structure is integral to the spatial experience, with branching glulam columns and cantilevered forms shaping both the interior and exterior architecture.

The building opens generously to its surroundings through multiple entrances and shaded outdoor areas, creating a seamless transition between inside and out and reinforcing its role as an open and accessible mass timber building.

Sustainability in Practice – Responsible Mass Timber Construction

The Rubenstein Treehouse serves as a model for environmentally responsible mass timber construction:

• Timber construction stores carbon throughout its entire service life and thus makes a positive contribution to climate protection.
• The design supports zero fossil fuel combustion on-site and a significant reduction in energy use through rooftop solar panels, a connection to Harvard’s District Energy Facility, and other strategies.
• Bioswales work in combination with a rooftop collection system to retain and reuse rainwater.
• Interior materials were selected to meet high health and environmental standards, aligned with Harvard’s sustainability goals.

By combining innovative timber engineering with a strong architectural design, the Rubenstein Treehouse demonstrates how mass timber and glulam structures can meet the demands of modern institutional architecture - both in terms of performance and sustainability. The HASSLACHER group is proud to have contributed to this forward-looking public building project.