Rooted in local geology, ecology, and climate responsivity of Washington DC’s Palisades, the Butterfly Pavilion is a pool house that cascades down a 25’ slope. The pavilion’s roof form maximizes daylight, gently resting atop the site’s subsurface composition of soil and ancient metamorphic rock shaped by tectonic collisions and glacial runoff of the site’s unique geological history. This steep, wooded landscape — typical of the Palisades — offers a rich ecological matrix of native flora from which the structure is sculpted and conceived.
The pavilion accommodates a 75’x18’ lap pool, half the length of an Olympic pool, to serve a multi-generational family of avid swimmers. Here, grandparents and parents — both former collegiate athletes — can maintain strength as they age, while offering their children a year-round environment to train competitively and enjoy recreationally. In a climate characterized by cold winters and humid summers, the pavilion leverages geothermal stability by partially embedding into the ground. The innovative roof structure reduces solar gain with a ‘Cool Roof’ (solar reflective surfaces). Its shape inverts opposing trusses that reach toward the rising and setting sun. Skylights carve into the butterfly roof, bringing light into the sheltered pool level while minimizing glare and mitigating thermal gain during hot summers. The pitched ceilings and apertures promote stack effect (convective rise of heat/moisture) within the butterfly roof, significantly reducing HVAC loads. The structure emerges from the sloped terrain to reveal a 110’ window wall wrapping the southwestern edge of the pavilion and extending toward a garden of native plants. Rain gardens absorb storm water, prevent erosion, and support pollinators. Auxiliary spaces — changing rooms, bathroom, and gym — are organized along the street wall and accessed through a seamless connection between old and new.
The Butterfly Pavilion is a threshold between building and landscape, becoming an ecological outcrop of the terrain. As a site-responsive intervention, the pavilion extends topography, responds to seasonal conditions, and supports a design ethos grounded in environment and contextual sensitivity.
Category:Sustainable HousesYear:2025Location:Washington, DC, USAArchitects:LA DALLMAN ArchitectsDesign Team: James Dallman, Grace La, Oonagh Davis, Belle Delatour, and Elias BennettClient: PrivatePhotographer: Courtesy of the Architects
