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United Therapeutics Plans D.C. Area's First Full Mass Timber Office Building in Silver Spring

MBS Staff
United Therapeutics Corporation Unisphere Annex Expansion Proposal Mass Timber Office Building in Silver Spring

United Therapeutics Corporation Unisphere Annex expansion in Silver Spring could be the first fully complete mass timber office building in the Washington, D.C. area.

The Washington, D.C. area could be getting another mass timber project, but this time, completely new from the ground up.  

United Therapeutics Corporation (NASDAQ: UTHR) — the D.C. region's largest biotech with headquarters in the area — has proposed using the state-of-the-art building methods to create a new office building in downtown Silver Spring.

Approximately 100,000 square feet, the building would stand five-stories and 105’ feet in height, including a massive solar array covering two sides of the building. The former Hilton Hampton Inn and Homewood Suites hotel at 8728 Colesville Road (previously an office building) would be demolished to make way for the cutting-edge building. Standing at 145’ feet tall, it would be one of the tallest buildings in the region ever to be knocked down.

The new structure would be an expansion of the most environmentally friendly office campus in the D.C. area. The entire campus including the main building called the Unisphere at 1000 Spring St, is a world-renowned and sustainably designed engineering marvel.

It is the world's largest net zero office campus and utilizes geothermal wells and pipes running 500‘feet into the ground. Several photovoltaic solar cell arrays cover the top and sides of the buildings.

The Unisphere Annex, as United Therapeutics calls it, would utilize advancements in design including building integrated photovoltaic arrays (BIPV), reduced carbon emissions from a mass timber structural system, and reuse of the below grade foundation.  

According to Zurich, a mass timber structural system consists of materials fabricated from layers of wood laminated together with a strong adhesive placed under great pressure. There are several processes involved including Cross-laminated timber (CLT), bonding smaller wood components or dimensional lumber at 90-degree angles for added strength. Another method called Glue-laminated timber (GLT) framing uses similar bonding methods in parallel.

While 80 M Street in the Navy Yard neighborhood of the District is already completed, that mass timber project by Columbia Property Trust simply added an additional three floors to an existing seven floor concrete and steel office building.

One very important fact not to be left unsaid as a major contributor to United Therapeutics’ net zero environmental goals is the surrounding environment. Being in an urban district like downtown Silver Spring — an area with a 99-walk-score — is in high contrast to the greenfield developments in suburban areas. It is also a model being the first urban biotech campus in the region.  

United Therapeutics consulted the original campus designer, Philadelphia-based EwingCole, for the proposed expansion.   

The Unisphere Annex is a nod to the Biotech Priority Campus Policy, also known as Zoning Text Amendment 21-09. It was passed unanimously by the Montgomery County Council and spearheaded by Councilmember Andrew Friedson.  

BioHealth facilities that are 150,000 square feet or larger, or existing BioHealth facilities expanding by 50,000 square feet or more, will cut their application approval time from 600 days to 160 days or from 18 months to less than six months.

In March, Freidson and Councilmember Nancy Navaro led the passing of the Biohealth Opportunity Zone Incentive Program, which provides a grant of $250,000 to any Biohealth Priority Campus located in a County Opportunity Zone. The Unisphere Annex in downtown Silver Spring would qualify for the incentive.

This is the second office building proposal in downtown Silver Spring within a year from United Therapeutics. In June 2021, the company submitted plans for a 65,000 square foot organ manufacturing facility. The biotech is the mastermind behind the first successful xenotransplantation of a pig heart which was conducted at the University of Maryland Medical Center in Baltimore.

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