Hirshhorn Museum Sculpture Garden Revitalization

The underground passage linking the Hirshhorn’s Sculpture Garden to the museum plaza beneath Jefferson Drive has been closed since 1993. For 33 years the campus has been cut in half by a road.

The 1.3-acre sunken garden is part of Gordon Bunshaft’s 1974 SOM campus on the National Mall, and its problems are as much structural as aesthetic: advanced concrete decay and a failed waterproofing membrane. The revitalization reopens the passage, replaces the membrane and concrete, and overhauls stormwater management on a site with almost no room to work.

Project Scope

Hiroshi Sugimoto of New Material Research Laboratory is design architect, with Quinn Evans as architect of record and Grunley Construction as general contractor. The redesign reorganises the space for 60 artworks, a 50 percent increase, set within nearly 30,000 new plants and trees, and introduces a stacked-stone wall treatment. That treatment drew sustained objections from preservationists across a three-year public review before the National Capital Planning Commission and the Commission of Fine Arts approved it unanimously. Groundbreaking was November 2022, construction started November 2023, and the garden reopens 31 October 2026. A separate envelope repair to the museum drum is running on the same campus.

The cost figures don’t reconcile across sources. The Smithsonian states a US$68 million project cost from public and private funding; Grunley’s construction contract has been separately reported at $71 million; a 2021 source cited a $60 million budget. Those are three different numbers measuring three different things, and none of the parties has published a bridge between them.

Why It Matters

Waterproofing a below-grade structure under a public plaza, on the National Mall, without closing the museum above it, is the kind of job where the design conversation gets all the attention and the membrane detail decides whether the work lasts. The original lasted about 19 years before the passage closed.

The preservation fight is worth noting too. Bunshaft’s garden is barely 50 years old and already carries enough standing that a stone wall took three years to approve. Mid-century modern civic landscape is now heritage fabric, with all the review that implies, and project teams pricing similar work should assume the schedule reflects it.

Project Team & Details