At a time when urban centers are expanding rapidly and environmental concerns are at the heart of the debate, building on existing structures is a major challenge. It is now essential to consider the second life of buildings right from the design stage.
Although industry professionals are starting to take the plunge, this necessary change of direction remains a technical and technological challenge. Trimble's experts take stock.
Renovation in the age of metropolization
What are we talking about?
Renovation work can involve a number of different aspects:
building structure;
technical installations (plumbing, electricity, heating, etc.);
thermalinsulation;
regulatory compliance;
rehabilitation of facades ;
change of use (e.g. from office to home), etc.
This diversity of projects calls for advanced technological solutions to guarantee optimum results.
Market figures in close-up
According to data from the Fédération Française du Bâtiment (FFB - French Building Federation), the
new-build crisis
continues, with a significant year-on-year fall of 10.2% over three months to the end of April 2024 for new housing, and 8.2% for non-residential. Although less dynamic than in the last quarter of 2023, the improvement and renovation sector continues to grow, posting +1.7% over the same period, with a similar performance for energy renovation (+1.5%).
Why build on existing structures?
Environmental issues
Environmental issues have become a priority in the construction sector. And with good reason, energy performance standards are gaining in importance, particularly with the rise of ESG (Environmental, Social and Governance) standards and the application of the tertiary sector decree requiring a reduction in energy consumption.
At the same time, there is a growing political will to eliminate " energy wastes " from existing buildings.
What are the objectives of the tertiary sector decree?
The tertiary sector decree sets ambitious energy reduction targets for owners and operators of tertiary sector buildings. The aim of the decree is to achieve energy savings of 60% by 2050 for the entire tertiary sector building stock.
Societal and demographic challenges
In large urban centers, where space for new construction is limited, vertical building has long been the preferred option, despite the high costs involved.
Today, the emphasis is more on economy and efficiency in architectural projects. A trend that raises the question of rehabilitating premises or adapting their use according to need. The aim is to revitalize existing buildings by retaining or modifying their original function, while adding new uses.
The Covid-19 crisis has accentuated this trend, leading, for example, to the transformation into housing of large office complexes abandoned due to telecommuting. At a time when city centers are facing a housing crisis, the predominance of office space is exacerbating the situation. In Île-de-France, this stock will reach 56 million square meters by 2023.1
In this context, the emphasis is no longer solely on the quantity of these buildings, but also on their performance. The aim is to breathe new life into existing structures by adapting them or giving them new uses, while retaining or modifying their original function.
The challenges of a renovation project
Building on existing structures is a real challenge. It often involves major changes, such as the modification of vertical circulation, space and emergency exits, and in some cases, the addition of storeys (elevation). All these alterations must be carried out with due regard for the existing structure, whether it's an empty plateau or the building's skeleton.
As a result, the financial and technical cost of renovation is sometimes higher than that of new construction. And with good reason:
planning on existing structures presents significant spatial constraints, making it crucial to take measurements on the existing structure to ensure the relevance of the renovation;
moving around in an existing space can pose problems when it comes to transporting and installing bulky elements, as well as organizing teams on site;
ensuring business continuity in and around the areas concerned is an additional challenge for industry professionals.
What solutions are available for my renovation projects?
BIM: greater reliability for renovation and operation
BIM comes into play at every stage in the life of a building, to make your projects simpler and more reliable. Just as in new construction, BIM promotes better collaboration, fewer errors, optimized costs and deadlines... The secret? A
3D modeling
in the context of existing construction, BIM offers two major advantages:
It facilitates the modeling of a new project on an existing framework after a precise on-site data survey. You can then inject this data directly into your modeling tools, giving you a reliable basis on which to tackle phasing.
It provides access to precise data, via a model that is faithful to the existing building, facilitating building maintenance and any future renovations.
The tools associated with BIM enable you to set up a BIM workflow consisting of data capture, processing and visualization by all project stakeholders.
The renovation market is undoubtedly a solution for revitalizing the ailing construction sector. Indeed, the trend echoes contemporary challenges that industry professionals can no longer ignore. While this complex challenge calls for technological adaptation in the sector, BIM represents a real opportunity.
