Sustainable & efficient: construction in existing buildings
A lack of living space, a shortage of space in urban and suburban areas, long construction times and high construction costs as well as a change in usage behavior have led to the fact that construction in existing buildings, i.e. the conversion of buildings, is becoming increasingly relevant - especially against the backdrop of climate change and dwindling resources. In this blog post, we will discuss both the advantages and the challenges of converting existing properties and present current conversion examples from ECE Work & Live.
Construction in existing buildings: the definition
Constructionin existing buildings refers to the structural alteration, modernization, renovation or conversion of existing buildings or structures.
These are developments that build on existing structures instead of constructing new buildings on undeveloped land. The aim is to maintain or improve the value and usability of a property without completely replacing the existing structure.
Existing buildings as a solution for scarce living space
Housing is in short supply. In metropolitan regions in particular, population growth combined with stagnating new construction activity is leading to an immense housing shortage accompanied by significant price increases. New construction projects pose many challenges.
In addition to high construction costs and rising interest rates, the defect of suitable and affordable plots of land makes the realization of urgently needed living space more difficult. The same applies to the hotel asset class. In attractive city center locations, new buildings are often no longer feasible as there are virtually no suitable plots of land and the demolition of existing old buildings is too expensive.
Discover our article on the residential of the future and urban development of the future.
Over 20,000 apartments through change of use from commercial to residential space
Due to changing requirements for contemporary, modern offices and a high proportion of people working from home, it is reasonable to assume that offices that are no longer needed can be converted into apartments or hotels on a large scale. A study by JLL in 2023 came to the conclusion that almost 20,000 apartments could be created by 2025 by converting vacant office space in the seven A-cities of Berlin, Düsseldorf, Frankfurt, Hamburg, Cologne, Munich and Stuttgart.
ECE Work & Live is convinced that excellent residential or hotel projects can be developed by refurbishing office buildings that are no longer usable. It is already proving this at three sites. However, it is clear that it is not possible to simply write blueprints that can be used to develop standard products; rather, construction in existing buildings requires a decidedly case-by-case examination - even more so than a new building development.
Advantages of construction in existing buildings: saving on gray emissions
Sustainability is a key advantage of converting disused existing properties. By converting an existing building, the sealing of additional areas is avoided, thereby conserving the valuable resource of land.
Another important aspect is the saving of gray emissions that have already been incorporated into the original construction of the property. This saving is made possible by preserving and using the existing building fabric. This reduces the use of building materials such as concrete, and materials that have already been used are naturally given a new life cycle.
Concrete is the most frequently used building material in Germany and, according to dena, contributes significantly to emissions in the building construction sector with 16 million tons of CO₂ equivalents. The reuse of concrete and other building materials is therefore hugely beneficial from a sustainability perspective.
In addition to the ecological benefits, under construction also offers economic advantages:
- The existing building shell saves time and money.
- Funding opportunities, such as those offered by KfW for energy-efficient refurbishment, support the economic viability of conversion projects.
A current ECE Work & Live project illustrates the benefits: The conversion of an office property into a hotel in Rome was investigated by CAALA, a software and consultant specializing in sustainability.
The results:
- 13 % reduction in greenhouse gas emissions over the entire life cycle compared to a new building.
- Almost 50 % reduction in gray emissions by preserving the building fabric.
Challenges of conversions in existing buildings
Converting existing properties into residential buildings or hotels poses numerous challenges that need to be carefully examined. Not every property is suitable for this type of use.
Important criteria for conversion
- Technical requirements including
- Room depth of the Property
- Ceiling heights
- Incidence of daylight
- Sound and fire protection requirements
- Area sizes and layouts
- Adaptation to the existing structure:
- It must be checked in advance whether the desired room concept can be implemented within the existing property.
Challenges due to renovation work
The actual time and cost advantages of the existing shell can be negated by the following factors:
- Costly renovation work on the structure
- Alterations to the supporting structure
- Removal of building pollutants
- Compliance with current fire protection requirements, which often require retrofitting
- It must be checked in advance whether the desired room concept can be implemented within the existing property.
Special features for listed properties
Careful preliminary examination (due diligence) is essential for listed properties in order to avoid unforeseen problems. These developments require an even greater degree of flexibility and creativity in order to preserve the listed structure on the one hand and to make optimum use of the space on the other.
Economic obstacles
- Book values as a hurdle:
Portfolio holders tend to wait for demand for office space to recover rather than depreciate the book values of their vacant properties on a large scale. - High acquisition costs:
Developers can often only make developments economically viable if they acquire the properties cheaply. Refurbishing existing properties is usually not significantly cheaper than a new building.
Exciting in this context: Lean Management in construction projects
Planning law challenges
- New planning law required:
The conversion of an office building into residential space usually requires the creation of new planning law, which usually involves a development plan procedure. - Time-consuming approval processes:
These procedures can take several years and are often difficult to predict. - Flexibility through exemptions:
In order to use existing buildings efficiently, it is important to allow conversions by means of exemptions from the applicable planning law.
Construction in existing buildings: examples from ECE Work & Live
ECE Work & Live is demonstrating its competence and expertise in the conversion of existing properties with three current developments in major European cities.
Rome: From office to hotel
In the heart of Rome, ECE Work & Live is currently converting a listed building that was previously used as an office building into a hotel for the lean-luxury hotel group Ruby Hotels. On a gross floor area of 6,700 m2, 164 rooms are being created spread over six floors as well as a rooftop bar. The property will be certified with a DGNB sustainability label. The aim is also for the building to be taxonomy-compliant and achieve the GOLD certification level. The hotel is scheduled to open in 2025.
Copenhagen: New hotel instead of offices
In Copenhagen, too, ECE is currently developing a hotel to modern energy standards, which will replace an office redevelopment project on the attractive main shopping street Gammel Kongevej in the independent district of Frederiksberg to the west of the city center. To this end, the company acquired the plot of land with the former office property and an Existing / As-built space of around 7,600 m2 gross floor area in spring 2024. The planned design hotel with more than 200 rooms is due to be completed in early 2027.
Düsseldorf: Sustainable apartments instead of offices
In Düsseldorf, ECE Work & Live is planning to convert a former office property into an attractive and sustainable residential building with around 150 modern tenants or owner-occupied apartments. A special feature of this project is that the three-part building from the 1970s is centrally located in a residential area close to the zoo park, which is considered the city's green lung with its pond, meadows and playgrounds. In addition, the building's development plan already designates it as residential, so there is no need to draw up a new development plan.
Conclusion on construction in existing buildings
The conversion of existing properties - especially disused office buildings - into apartments and hotels offers great potential, despite the technical and planning law challenges mentioned above, primarily due to their sustainability.
Construction in existing buildings will therefore play an increasingly important role in the real estate industry. However, due to the severe housing shortage, conversions alone will not be enough, so new building will continue to be necessary for housing in the future.
ECE EDITORIAL TEAM
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