Brunet Saunier & Associés

Many of us - architects, engineers, developers, philosophers, sociologists, etc. - are questioning the future forms of hospitals, wondering what hospitals will look like in 20, 50, or 100 years. We are trying to outline what some call, as a slogan, “the hospital of the future.”
However, we are also part of a context of climate change and resource scarcity that leads many experts to anticipate a significant slowdown in new construction (in favor of rehabilitation or restructuring projects of existing heritage).
Indeed, to achieve carbon neutrality by 2050 as it has committed to, following the Paris Agreement, as part of the Climate Plan (1), France will have to divide greenhouse gas (GHG) emissions in its territory by 6 compared to 1990. This considerable effort will necessarily go through a reduction of GHG emissions in the sectors that contribute the most to the national carbon footprint, starting with the building sector, which represents 25% (153 Mt CO2e in 2019) of France’s annual carbon footprint (2).
We are already seeing the effects of this paradigm shift in the construction of housing or offices. But what about hospitals, whose new projects are still mostly new operations, or demolition-reconstruction? In the post-carbon world that is still largely to be invented, is it possible that “the hospital of the future” is not a new object to produce, but an “already-there”, a heritage to transform and reinvest in?
To answer this question, we must first identify the specificities of hospital buildings, built or to be built.

Let’s start with an observation: the lifespan of hospitals is constantly decreasing. From the first hospices that remained places of care for nearly five centuries (Hospices de Beaune, 1475-1971, Ospedale Maggiore di Milan, 1470-1932), to the large university hospitals of the 1970s, many of which are considered obsolete only fifty years after being put into service (CHU de Caen, 1975-2026, Hôpital Bichat Claude-Bernard, 1970-2028), passing through the comb-shaped typologies of the 19th century (Hôpital Lariboisière, 1854-2026), or the so-called “monobloc” hospitals of the 20th century (Hôpital Beaujon, 1935-2028), we are witnessing an increasingly rapid obsolescence of hospital buildings.

1 - Timeline: Hospital Lifespan from the 15th Century to the Present

This raises many questions: Should we resign ourselves to a kind of fatality in the face of this curve that seems unwilling to reverse? Are we facing a form of “planned obsolescence” of buildings, which would not be able to accommodate the mutations of medicine and technology? Are we engaged in a vain race, as the decoupling between the long time of architecture and the increasingly rapid time of technology seems to be proven (3) ?

If we are to consider restructuring rather than building from scratch, we must also say a word about the available hospital heritage, largely inherited in France from the 1960s and 1970s, and which presents recurring and well-identified weaknesses :

• The presence of asbestos and lead, which increases the cost of operations and complicates interventions on occupied sites ;

• The classification of certain buildings as “high-rise buildings” (IGH), leading to operational and fire safety constraints ;

• Common typologies known as “tower on a base” involving intensive use of elevators, which shuttle between hospitalizations (in the tower) and the technical platform (in the base), with problems of excessive waiting at floor landings ;

• Finally, often low floor-to-floor heights, which limit the possibilities of reallocating the premises to technical uses (or even simply to hospitalizations meeting current standards).

2 - An example of a “tower on a base” : the Caen University Hospital, or the “hospital-ship”, 1966, architect Henry Bernard (1912-1994)

Finally, a unique characteristic of hospital projects lies in a singular breakdown of construction costs, with a predominance of technical systems. We calculate that these systems account for 36% of the total cost for a new hospital project, compared to only 27% for a tertiary building project (4).

3 - Breakdown of construction costs by macro-lots for a new tertiary project (left) and a hospital project (right)

By cross-referencing these data on the breakdown of construction costs with those from the E+C- observatory on the carbon footprint of recent tertiary projects, we seek to estimate approximately the breakdown of the carbon footprint for a new hospital project, across 5 macro-lots: structural work, envelope, secondary works, technical systems, site development and landscaping.

Based on this, we then estimate (necessarily in an approximate and qualitative manner, as this value obviously depends on the specific characteristics of each project) the “portion to be subtracted” in the case of a restructuring for each macro-lot, with an equivalent built-up area :
• Structural work: 90% (preservation of almost all of the existing structure, no new foundations, marginal structural repairs for new openings/wells and associated waste production) ;
• Envelope: 20% (thermal performance objectives generally lead to installing a new, more efficient façade - insulation, cladding, frames - and a new waterproofing system after re-insulating the roof) ;
• Secondary works: 10% (the change of use of the premises often involving a stripping of the existing and a new interior layout. The value retained nevertheless takes into account the possibility of reusing a certain number of existing secondary elements) ;
• Site development and landscaping: 50% (in the case of a renovation, it is considered that about half of the exterior facilities can be kept as is) ;
• Technical systems: 0% (upgrading, the search for energy performance, the modernization of medical technologies generally lead to a complete overhaul of the building’s technical systems, whether in a new or restructured operation).

4 - Assessing the ‘carbon gain’ of a hospital renovation project compared to new construction, maintaining the same built-up area

Ultimately, we arrive at a ‘carbon gain’ on construction products and equipment (CPE) of around 30% for a hospital project carried out through renovation rather than new construction, with an equivalent surface area.

To be precise, however, this order of magnitude must be nuanced by two observations :

1. The share of CPE in the complete carbon footprint (life cycle analysis over 50 years) of a new project being around 64% (5), the actual ‘carbon gain’ over the entire life cycle is reduced to approximately 64% x 30% = 19% ;
2. These ‘theoretical’ values have a significant margin of error due to the methodology used. They can also be revised upwards if we add the impact of any demolitions in the context of a demolition-reconstruction operation.

This initial theoretical study provides useful initial orders of magnitude but does not allow us to dispense with a meticulous examination of the concrete cases encountered in practice, each context being of course unique and calling for always specific answers. This is why we propose to nuance this first statement, based on three projects by the agency Brunet Saunier & Associés, which correspond to three opposing approaches :
• 1. Rebuild everything? (from Bichat and Beaujon to the future CHU Saint-Ouen Grand Paris Nord)
• 2. Rehabilitate everything? (Laveran Military Instruction Hospital, Marseille)
• 3. A hybrid strategy combining new construction and rehabilitation (Simone Veil Hospital, Blois)

1. Rebuild everything? (from Bichat and Beaujon to the future CHU Saint-Ouen Grand Paris Nord)
   Beaujon Hospital in Clichy (1935), built by Jean Walter, and Bichat-Claude Bernard Hospital (1980), a work by Raymond Marchand, Henri Santelli and Jean Seac’h, are two major examples of 20th century hospital architecture, respectively paragons of two major hospital typologies: the single-block hospital and the tower on a base.

5 - Beaujon Hospital in Clichy (1935) and Bichat-Claude-Bernard Hospital (1980) are two iconic examples of 20th-century architecture

The first, inspired by American skyscraper architecture and representative of the hygienic and functionalist culture of the time, has great heritage value, as evidenced by the label “Remarkable Contemporary Architecture”. The second is the latest incarnation of the “tower on a base” hospital model, with a cross-shaped tower resting on a 4 to 6-story base.

Beyond their technical, regulatory, and medical obsolescence, these two buildings are characterized by their urban location, on hospital sites where land is scarce, limiting the possibilities of reorganization “on itself”. The AP-HP has therefore chosen to bring together the main activities of these two hospitals in a new facility to be located in Saint-Ouen: the Grand Paris Nord University Hospital Campus, whose studies are being carried out jointly by Brunet Saunier & Associés and RPBW.

2. Full rehabilitation? (Laveran Military Instruction Hospital, Marseille)
   In contrast to this approach, some clients may be tempted to fully rehabilitate their existing buildings in service, minimizing the creation of new surfaces. This was the case for the Laveran Military Instruction Hospital in Marseille, whose studies were conducted by Brunet Saunier & Associés and Panorama Architecture.

Originally, the mission was to revise the installations, bring them up to standards and reorganize the functional layout of certain services, with a planned construction period of 5 years and a project cost of nearly 50 million euros excluding tax.

At the end of the preliminary design phase, after a complete diagnosis of the existing technical installations and definition of the project and phasing, the assessment was quite different: the construction period doubled, with more than 20 phased works, and an estimated project cost of 70 million euros excluding tax. As a result, the client ultimately decided to abandon the project and launch a new tender for a new project on a new site.

This unfortunate experience has convinced us that phasing is the key to successfully managing a renovation project on an occupied site, as illustrated by our last example.

3. A hybrid strategy combining new construction and rehabilitation (Simone Veil Hospital, Blois)
   Minimizing the number of phased works to reduce construction time and limit risks (aspergillosis, asbestos, etc.) and nuisances (noise, dust, etc.) associated with work on an occupied site: this was the fundamental idea that guided our design during the competition for the Simone Veil Hospital in Blois (6).

To achieve this, the project is based on a strategy of “land sobriety” which plans to bring together the new surfaces - which the feasibility study initially split into 5 buildings - within a single extension, built in one go. This approach has two main advantages :
• It simplifies the phasing by reducing the number of successive phased works ;
• It saves land and limits its artificialization, while leaving a large land reserve to the North of the site to allow for future developments.

6 - New space layout strategy: “land sobriety” (project, right) versus “land exuberance” (feasibility study, left)

The new extension seamlessly continues the existing base, extending its facades and patios. The “spatial continuum” of the base, a functional and adaptable feature, is thus preserved and amplified.

7 - The new extension seamlessly continues the existing base, creating a functional and adaptable spatial continuum

This continuity is expressed on the facade by a common treatment of the base over two levels, clad in a new earth-toned concrete facade throughout the project.

8 - Perspective view of the project from the access road: the new part (in the foreground) and the existing part (in the background) are connected by a two-level base with a unified facade design

The new building is designed as a structure approximately 64m by 78m, with a series of flexible and adaptable floors supported by a concrete post-and-slab structure on a 7.5m by 7.5m isotropic grid. Natural light enters the building through regular openings in the perimeter facade and patios.

9 - New extension : structural framework and natural light provided by the perimeter facade and patios

The existing tower, once emptied of its current functions (transferred to the new part), will be renovated to accommodate tertiary functions and a boarding school. These non-technical functions are well-suited to the bar-shaped morphology of the existing structure and its relatively low floor heights.
The project aims to preserve the unique aesthetic of the building by Jean Seac’h, characterized by an alternation of glazed verticals (curtain walls) and opaque verticals (prefabricated curved washed concrete modules). The high-quality and durable concrete facade elements will be retained and insulated from the inside, while the curtain walls will be removed and replaced with high-performance mixed wood-aluminum frames equipped with retractable and orientable exterior sunshades to effectively modulate solar gains.
Continuing the vertical scansion of the existing facade, double-height loggias will be cut into the thickest tower to bring light to the heart of the floor. Professionals will thus benefit from generous terraces to improve their quality of life at work.

10 - Perspective view from the entrance plaza: above the base, the restructured existing building rises, with its facades undergoing a respectful renovation

This study opens up new avenues for understanding how to approach the restructuring of hospital heritage. But it also leads us, through a critical analysis of the existing structures we have inherited today, to take a fresh look at how we build new buildings. More than ever, it seems essential to us today to design new buildings with the understanding that they will surely outlive their original function: we must therefore build ‘rehabilitable new’ structures. This is another way of saying what Mies Van der Rohe so brilliantly expressed in 1958 :

To achieve this, we propose to see the hospital as a puzzle, in which there is always an empty space that allows for the permutation of pieces. In the same way, it is imperative to always leave “empty spaces” for the hospital, at all scales :

• At the site scale, to prepare for future developments of hospital sites, hence the crucial importance of hospital master plans ;

• At the building scale, to allow for its transformation in the future. For example, in our project for the Saint-Ouen Grand Paris Nord University Hospital, the tertiary sectors, present on each floor and well connected to the various care services, constitute valuable surface reserves for potential future extensions of care activities. That is why they are designed from the outset on the same model as the care services (identical structural grid, floor heights and operating loads, double circulation, oversized technical rooms and shafts, etc.). This “upward harmonization” is an initial investment that opens up a range of possibilities by not freezing the offices from the outset in a specific form.

More generally, building “rehabilitable new” involves seeking a certain neutrality of the plan and the façade, to enable changes of use over time. This reaffirms the relevance of the “monospace”, a hospital typology that Brunet Saunier & Associés invented in the 2000s, and which the agency continues to develop and evolve in ever-different contexts, in new or restructuring operations, in isolated hospital sites or in dense urban environments.

(1) The Climate Plan, presented in July 2017 by the Ministry for the Ecological and Inclusive Transition, sets new objectives for France, including achieving carbon neutrality by 2050. Since the law of November 8, 2019 on energy and climate, this objective has been enshrined in law.
(2) Two-thirds of these emissions are due to direct and indirect emissions related to the operation of existing buildings (scopes 1 and 2), and one-third is due to construction products and equipment (CPE) used in new construction and renovation projects.
(3) On this point, we are actually much more optimistic. We argue instead that the observed obsolescence comes from the successive advent of modern medicine in the second half of the 19th century (Semmelweis discovered hygiene in 1847, Louis Pasteur discovered asepsis in 1860, and Joseph Lister discovered antisepsis in 1863), and from the functionalist movement in architecture in the 20th century, which led to over-specification and verticalization of built forms, undermining flexibility, which remains the best guarantee of the durability of structures.
(4) Data source: representative tertiary and hospital projects carried out by the agency Brunet Saunier & Associés over the past 15 years.
(5) Source: E+C- Observatory (value corresponding to tertiary projects).
(6) Competition for which Brunet Saunier & Associés was selected as the winner in 2023.
(7) MIES VAN DER ROHE Ludwig, remarks collected by NORBERGSCHULTZ Christian, “Rencontre avec Mies van der Rohe”, Architecture d’Aujourd’hui n°79, 1958, p. 40.