Our work
209-213 Pennsylvania Ave SE
209-213 Pennsylvania Avenue, a nearly 100-year-old structure on historic Capitol Hill in Washington, DC, needed a major renovation that involved lowering two existing basements by approximately eight feet
The Project
209-213 Pennsylvania Avenue, a nearly 100-year-old structure on historic Capitol Hill in Washington, DC, needed a major renovation that involved lowering two existing basements by approximately eight feet. The complex undertaking required sequential underpinning around the perimeter, temporarily reinforcing a central party wall, and addressing unforeseen foundation challenges with a neighboring property. Steele Foundation executed meticulous sequential underpinning and structural shoring despite dense urban conditions and limited site access from Pennsylvania Avenue.
The project, completed in collaboration with architect CORE, structural engineer Rathgeber/Goss Associates, geotechnical engineer GEI Consultants, and general contractor McCullough Construction, showcased technical excellence through innovative load testing and precise underpinning operations. This craftsmanship earned Steele Foundation the prestigious Washington Building Congress 2025 Craftsmanship Award in the “Underpinning, Foundations & Excavations” category.
year
2024
Location
209-213 Pennsylvania Ave SE, Washington, DC
Scope
Underpinning, Test Pitting, Load Testing, Structural Shoring
Category
Building Renovation, Office
General Contractor
McCullough Construction, L.L.C.
Consultants
Architect: CORE
Structural Engineer: Rathgeber/Goss Associates
Geotechnical Engineer: GEI Consultants
Challenges and Results
As with many complex basement-lowering projects in a dense urban environment, 209-213 Pennsylvania Avenue SE presented unique structural and logistical challenges. The most immediate challenge stemmed from the party walls and the project’s impact on neighboring properties. To the east, the concrete foundation of one adjacent building sat five feet above the 213 basement level, presenting an unforeseen challenge that required precise sequential demolition, underpinning, and temporary shoring to maintain stability. Additionally, limited site access prevented standard soil testing, necessitating custom load testing solutions to confirm bearing capacity.
Our team remained adaptable throughout the project, revising methods and sequencing to execute each phase safely. Installing temporary piers and steel channels provided openings between the 209 and 213 basements, ensuring construction could progress without disrupting the center wall. Careful planning and phased coordination minimized disruption to the surrounding community while keeping the project on track.
By leveraging innovative load testing, strategic shoring techniques, and collaborative problem-solving with the project team, Steele successfully navigated the site’s challenges. The result was a structurally sound, lowered basement that met all design and safety expectations — reinforcing our reputation for excellence in foundation construction.
Why Steele Foundation?
Steele Foundation was selected to perform the complex work based on our long-standing relationship with McCullough Construction and CORE architects, who value Steele’s reputation for following all best practices of design and construction underpinning on challenging projects.
In this project, our proactive approach brought innovative solutions to initial planning meetings, which led to architectural improvements. Our expertise in party wall challenges, custom load testing methods, and precise underpinning techniques in restricted urban environments made us the ideal partner. The team’s collaborative expertise in developing meticulous excavation plans and sequential underpinning ultimately reduced underpinning requirements by 33% while ensuring complete structural stability.
