Ballston One Office-to-Residential Redevelopment, Arlington, Virginia

Penzance has broken ground on Ballston One, the redevelopment of a 240,000-square-foot office property at 4601 N. Fairfax Drive in Arlington, Va., into a seven-story, 328-unit apartment building. The developer announced the start on Oct. 30, 2026, after demolition got going earlier that week, and followed with a formal release on Nov. 2.

It’s billed as an office-to-residential conversion, but the more precise description is a replacement. The office building comes down. What stays is the two-level underground parking garage, which Penzance will reuse and upgrade rather than dig a new one.

Project Scope

The approved plan calls for 328 units, studios through two-bedroom-plus-den layouts, including 13 two-story loft homes. BKV Group is the architect. Penzance hasn’t publicly named a general contractor.

Keeping the garage is the core of the sustainability case. Penzance estimates it cuts the project’s carbon emissions by about 40% versus building new below-grade structure, and the building is targeting LEED Gold with roughly 24% energy savings. The spec includes bird-friendly glass, dark-sky lighting, a green roof, all-electric appliances, EV charging and low-flow fixtures. Tree canopy will cover about 16% of the site, above Arlington County’s 10% requirement.

Amenities run to about 80 square feet per unit: a courtyard pool with an outdoor kitchen, a rooftop terrace, a fitness center and yoga studio, a coworking lounge, a makerspace and 24/7 concierge.

Off-site, the developer is building a shared-use path along North Fairfax Drive with new tree canopy and ADA-compliant crossings, tying the site to Ballston Wetland Park and the Custis and Bluemont trails. As part of its community benefits package, Penzance is putting more than $3.2 million into the county’s Affordable Housing Investment Fund.

Why It Matters

Penzance bought the building for about $25 million in 2023, and the Arlington County Board approved the redevelopment in July 2025 while a federal tenant still occupied the space. Three years from purchase to groundbreaking is quick for a Rosslyn-Ballston corridor deal.

The project is a useful reality check on conversions. Plenty of suburban-style 1980s office buildings can’t be carved into apartments that work, so developers keep the parts that hold value (here, an expensive below-grade garage) and rebuild the rest. Arlington gets housing about 800 feet from the planned second entrance to the Ballston Metro station, and the office vacancy rate loses one more building. Expect more projects in the corridor to follow the same playbook.

Project Team & Details