Ca’ delle Alzaie | © Andrea Sottana In Treviso, Italy, Ca’ delle Alzaie by Stefano Boeri Architetti proposes a nuanced model for urban residential living that interrogates the boundaries between architecture, landscape, and public infrastructure. Built between 2016 and 2021 on a former industrial plot along the river Sile, the project consists of three mid-rise residential buildings immersed in vegetation. The scheme addresses a complex array of urban and ecological concerns through an architectural language rooted in both environmental responsibility and spatial fluidity. Ca’ delle Alzaie Residential Complex Technical Information Architects1-4: Stefano Boeri Architetti Location: Treviso, Italy Gross Floor Area: 9,000 m2 | 96,875 Sq. Ft. Project Year: 2016 – 2021 Photographs: © Andrea Sottana In Treviso we proposed an unprecedented variation of our concept of Vertical Forest: not a tower, but three buildings surrounded by vegetation, with very different views of the surrounding landscape. In the next few years Treviso, with Milan, Utrecht, Brussels, Eindhoven, Munich, Cairo, Nanjing and many other cities in the world, will become the site of an innovative experiment to demonstrate that the architecture of the future will be able to host the cohabitation of more living species, becoming a fulcrum of biodiversity – as well as environmental sustainability. – Stefano Boeri Architects Ca’ delle Alzaie Residential Complex Photographs Aerial View | © Andrea Sottana Night View | © Andrea Sottana Facade | © Andrea Sottana Facade | © Andrea Sottana Facade | © Andrea Sottana Facade Corner | © Andrea Sottana Balcony | © Andrea Sottana Facade | © Andrea Sottana Stairs | © Andrea Sottana Contextual Framework and Urban Reconnection The site of Ca’ delle Alzaie occupies a residual industrial zone measuring approximately 11,000 square meters, positioned just outside Treviso’s historic core. Rather than simply introducing a residential development, the architects responded to a broader urban opportunity—the reweaving of a fractured edge condition between the city and its riverine landscape. At the heart of this reconnection lies the Restera pedestrian and cycling path, a linear public space parallel to the river Sile, which is reactivated and expanded through the project’s southern boundary. Pedestrian routes and embankments were not treated as peripheral or secondary but were designed as integral components of the project’s urban structure. The northern and southern slopes of the site are shaped into green infrastructure: flower meadows, tree-lined paths, and tiered gardens work collectively to soften the transition from public space to private domain. The southern retaining wall steps back in multiple locations to create moments of civic generosity—welcoming seating, bike stalls, and outdoor fitness elements that return spatial value to the community. This duality between public activation and private living is where the project situates its architectural relevance—not as an isolated object but as a porous system that negotiates the city’s thresholds. Ca’ delle Alzaie Spatial Organization Formally, the architecture avoids the temptation of monolithic repetition. The three residential buildings, while similar in height—each reaching seven storeys (27 meters)—are deliberately offset and rotated. This gesture disrupts the expectation of a linear riverfront wall. Instead, it produces a staggered composition that opens up framed views of the river while preserving visual permeability across the site. Each residential unit benefits from these spatial dynamics. Internally, the plan distinguishes between south-facing living areas and north-facing sleeping zones, ensuring natural light and river views to the spaces most frequently occupied during daylight hours. This sectional logic is mirrored in the facades, where orientation and program define the elevation strategy. With approximately three apartments per floor and a total of 60 units, the density remains moderate. Yet the spatial configuration offers a richness often absent in typical mid-rise housing. Large apertures, deep terraces, and the calibrated orientation of each building volume yield a diversity of micro-environments across units, resisting a one-size-fits-all typology. Beneath the buildings, an underground garage spans the full footprint of the complex. Rather than relegating this element to an infrastructural afterthought, the garage roof is transformed into a continuous green carpet. This elevated landscape supports communal gardens, vegetable plots, and the private gardens of ground-floor units. Here, program, structure, and landscape converge into a hybridized condition. Material Ecology and Vegetation as Architecture The architectural ambition of Ca’ delle Alzaie finds its most distinctive expression in its treatment of vegetation. Rather than serving as decorative greenwashing, plant life becomes both spatial material and ecological infrastructure. Over 50% of the total project surface—approximately 2 hectares—is dedicated to greenery. This includes 400 low-trunk trees, 170 full-scale trees, and 120 integrated directly onto building facades. This vertical forest strategy, developed in collaboration with agronomist Laura Gatti, draws from the ecological logic of the surrounding Sile Park. The palette of native plant species anchors the project within its environmental context and positions the building as an active contributor to local biodiversity. The architecture thus performs as a micro-ecosystem—a constructed habitat embedded within a larger urban-natural continuum. The facades, in particular, operate as living surfaces. The south-facing riverfront elevation is articulated through generous terraces, each three meters deep, designed to accommodate tree growth over time. Vertical planters punctuate the rhythmic horizontality, creating a facade of alternating solid and porous vegetated bands. The north facade is more restrained, projecting linear containers and vertical elements that house shrubs and smaller trees. The differentiation in planting strategy between the two orientations reflects both solar exposure and interior programmatic zoning. In this way, vegetation is not merely applied to the building; it is embedded in its architectural DNA—shaping its massing, regulating microclimates, and redefining the experience of inhabitation. Environmental Performance and Material Strategies In parallel with its biophilic agenda, Ca’ delle Alzaie engages with various sustainable design principles. Passive strategies such as solar orientation, natural cross-ventilation, and the strategic placement of vegetation collectively enhance thermal performance and acoustic insulation. Using trees and green surfaces contributes to mitigating urban heat island effects and airborne particulate matter while offering residents privacy and psychological comfort. Material selection further underscores the project’s ecological ethos. Anti-pollution paints and finishes were employed alongside renewable energy systems and durable materials selected for longevity and low environmental impact. Notably, these choices are not showcased as technological spectacle but are embedded quietly within the architecture’s systemic performance. The embankment—engineered as a flower meadow—functions as both structural infrastructure and green topography. It simultaneously conceals the subterranean garage, provides habitat, mediates between public and private realms, and creates continuity with the river’s edge. Thus, the landscape is not simply adjacent to the building; it is an active architectural medium. Ca’ delle Alzaie Residential Complex Image Gallery About Stefano Boeri Architetti ​Founded in 1993 by Italian architect Stefano Boeri, Stefano Boeri Architetti is an international architectural practice based in Milan, with additional offices in Shanghai and Tirana. The firm specializes in sustainable architecture, urban planning, and strategic urban development, focusing on integrating living nature into architectural design. Their notable projects include the Bosco Verticale (Vertical Forest) in Milan, a pioneering example of residential towers incorporating extensive vegetation to promote urban biodiversity. The firm’s work emphasizes environmental sustainability and has received numerous international accolades for its innovative approach to blending architecture and ecology. ​ Credits and Additional Notes Client: Cazzaro Costruzioni S.r.l. Landscape and Vegetation Consultant: Laura Gatti (Agronomist) Site Area: 11,000 sqm (approx.) Plot Area: 10,750 sqm