Alides upcycles Montoyer 34 to BREEAM Outstanding

For Montoyer 34 in Brussels' European Quarter, Alides set out to prove that retaining and transforming an existing building can meet ambitious sustainability and architectural requirements. Its Real Estate Upcycling strategy focused on maximising reuse while preparing the office building for the European Commission as tenant. With Encon supporting the BREEAM process from design through construction, the project achieved BREEAM Outstanding.

Upcycling an existing building without lowering ambition

Alides approaches ageing real estate from a dual position as investor and developer. Instead of automatically replacing end-of-life assets, its Real Estate Upcycling strategy examines how existing buildings can be retained and comprehensively renovated. At Montoyer 34, this meant preserving elements including columns, shafts, floor slabs, beams and masonry, with the existing concrete structure playing a central role in limiting embodied carbon.

The constraints were substantial. The plot has been almost completely developed for commercial use since the 1950s, leaving little space for greenery or technical installations. Limited internal height meant that ventilation could not simply be incorporated into the ceilings. Heat pumps and air-handling equipment had to be integrated underground, while ventilation ducts became part of the characteristic curved façade. At the same time, the design had to address thermal and acoustic comfort, energy performance and the requirements of the European Commission as future tenant.

Making BREEAM part of project decisions

Alides set the BREEAM Outstanding ambition before the European Commission became the tenant. Encon helped turn that ambition into requirements that could be managed throughout design and construction. BREEAM requirements were incorporated into specifications for architecture and building services before procurement, while Encon reviewed technical sheets with an impact on the certification and participated directly in decisions during execution.

The BREEAM assessment and project follow-up formed the core of Encon's services. Encon also had the technical breadth to support specific questions beyond the assessor role. When the European Commission requested a thermal comfort study, for example, Encon could provide the study without Alides having to appoint another specialist.

That combination is where Encon made a concrete difference. The BREEAM lead joined and led dedicated site meetings, communicated directly with engineers and contractors and continuously monitored requirements instead of leaving certification evidence until completion. This reduced the coordination burden for Alides and helped build a solid certification file during the project itself. The Design Stage certificate was obtained with limited feedback rounds, providing a structured basis for the subsequent post-construction dossier.

Outstanding certification strengthens an upcycled asset

Montoyer 34 ultimately achieved BREEAM Outstanding. The assessment reflects measures across the building: water-saving sanitary equipment and rainwater reuse, retention and recycling of materials, waste monitoring during construction, electrification and measures for visual, thermal and acoustic comfort.

The result also has a clear business dimension for Alides. BREEAM certification is part of its strategy for commercial developments, for which Alides targets at least Excellent. At Montoyer 34, the higher Outstanding ambition provides an independently assessed framework for the quality of a major refurbishment and supports the positioning of the building for a demanding institutional tenant.

Just as importantly, the project demonstrates how early integration can control certification risk. Requirements embedded in specifications, contracts and technical approvals are easier to manage than measures introduced after construction. For an investor-developer, that protects both the sustainability ambition and the quality of the resulting asset.