Bois Harel Tertiary Complex by ALTA – Sustainable, Contemporary Office Architecture in Saint-Jacques-de-la-Lande, France

Located at the dynamic edge of Rennes and Saint-Jacques-de-la-Lande, the Bois Harel Tertiary Complex by ALTA Architects represents a bold vision for contemporary office architecture. Completed in 2025, this 6,920 m² project transforms a former market gardening site, once defined by the Crublé greenhouses, into a sustainable, human-centered workspace. The site uniquely balances rural charm to the west with the urban energy of the Rennes ring road to the east, providing fertile ground for innovative architectural interventions that merge functionality, aesthetics, and environmental responsibility.

Design Concept

ALTA’s design introduces a connecting architecture—simple, contemporary, and sensitive to its surroundings. Two three-storey low-carbon office buildings rest atop a shared underground base, providing 170 parking spaces with electric vehicle charging stations and secure bicycle storage to encourage soft mobility. The buildings are designed to meet French 5th category ERP standards, ensuring accessibility, comfort, and efficiency.

Sustainable Construction & Materials

Sustainability is central to the Bois Harel project. The structural system employs 80% timber sourced from PEFC and FSC-certified forests, while concrete is used selectively only for essential structural components. Cross-laminated timber (CLT) floors, timber frame walls, and steel beams create spacious interiors with 2.70-meter ceilings, ensuring bright, healthy, and energy-efficient work environments. Timber naturally regulates humidity and improves indoor air quality, while delivering high acoustic and thermal performance.

The material palette combines subtlety, warmth, and durability. Spruce cladding and vertical elements provide texture and natural warmth. Natural anodized aluminum is used for windows and railings, offering elegance and durability, while zinc roofing and rainwater systems complete the environmentally conscious design. At ground level, permeable concrete and porcelain stoneware encourage water infiltration and ensure material continuity across the landscape.

Architecture in Context

The design emphasizes discretion and integration. Rooftop technical equipment is thoughtfully concealed to preserve the purity of the building’s silhouette. By stepping back and engaging with the surrounding landscape, ALTA proposes a human-focused office architecture that supports contemporary needs for sustainability, usability, and comfort. This restrained, forward-looking approach redefines urban development at the intersection of city and countryside.

Why It Matters

Bois Harel Tertiary Complex exemplifies sustainable office architecture, blending low-carbon construction, energy efficiency, and human-centered design. It reflects a modern, eco-conscious approach to urban edge development, redefining what office spaces can achieve in harmony with nature and urban life.

All Photographs are works of Gaëtan Chevrier