The building renovation sector has been moving towards the trend of using prefabricated renovation kits as an approach to effectively target the needs of any given project, and the design of kit-solutions that are able to respond to a range of requirements.
This method is mainly suitable for deep renovation operations, where insulation and additional layers can be superimposed to the external side of the pre-existing façade thereby improving the thermal envelope, with the substitution of windows, the integration of shading systems, the installation of mechanical ventilation systems, and the installation of photovoltaic or solar thermal modules in the façade.
Researchers across Europe are developing innovative prefabricated energy efficient building façade solutions that are equipped with high-performance insulation and have the possibility to incorporate solar panels as well as other technical installations, such as ventilation systems.
These solutions are built away from the construction site in a controlled industrial environment, and once delivered on the construction site can be assembled and installed in a very short period of time and so with minimum disturbance for homeowners or tenants that may remain inhabiting the building. One interesting example of this is the Prefabricated Multifunctional Timber Façade.
This is a renovation kit made of prefabricated timber-frame elements for building refurbishment. Its use is aimed at reducing costs, construction time and disturbance for occupants during the deep renovation process. At the same time, it enhances construction quality, durability and performance.
Single technology components, such as windows, doors, solar shading systems or external cladding will already be installed during the prefabrication stage to ensure the technical requirements such as airtightness, insulation quality and precision of the execution are met. Since the main insulation (and other components within the prefabricated modules) are well protected by the structure itself and the cladding, the façade maintenance is limited to the outer shell of the envelope. For all these reasons, these kits (also known as renovation packages) are considered the most cost-effective solution for retrofit.
The application of integrated kits for deep renovation is characterised by the fact that interventions on site are limited to the minimum. In a conventional retrofit approach, all the expected benefits are to be achieved through works performed individually and on the much less controlled environment of the building site. Alternatively, with the use of a prefabricated façade approach, an integral and complete planning process prior to implementation and assembling of the elements is required, and it becomes part of the strategy for avoiding failures and possible installation issues.
Currently roughly 75% of the building stock is energy inefficient, yet almost 80% of today’s buildings will still be in use in 2050. Hence the building sector is a key enabler for achieving the EU low carbon economy goals. However, the annual rate of renovation is well below the 3% required to reach the goal of the EU becoming climate neutral by 2050.
One solution is provided by prefabricated kit approaches who make energy efficiency measures more affordable: a reduction of overall renovation costs - cost associated to work on site and/or probable costs associated to a reduction of rental income or vacancy spans - allows for a more affordable overall execution.
Tackling energy consumption in the building sector in Europe is a real necessity, and researchers in many countries are studying the development and dissemination of energy-saving innovations. The H2020 project BuildHeat tested new solutions for the energy retrofit of multifamily buildings. At one of the project's demonstration sites, in Zaragoza, Spain, new ’ventilated’ façades have been installed.
A traditional ventilated façade consists of external tiles (stone, marble, bricks, stoneware etc.) and the anchoring systems are most often assembled on site. However, in this demo case everything was pre-assembled at a local workshop. In addition, the frames were hooked to the façade with a special type of bracket to allow an easy disassembly of each individual module.
Additionally, the tiles were made of Corian, a material with a high resistance to direct sunlight, and whose colour remains substantially unchanged over time. On site installation was demonstrated to be faster resulting in a reduction of the time spent on site. Moreover, disturbance to residents was also minimised.
Credits: BUILDHEAT project
The H2020 HEART project is developing a toolkit. The HEART toolkit incorporates different components and technologies, which cooperate to transform an existing building into a smart building. In developing this toolkit, the project advances and improves energy efficiency and the use of renewable energies in buildings across Europe.
Particularly in Central and Southern Europe where climate change is leading to increased electricity consumption both during summer and winter seasons. The core of HEART is a cloud-based computing platform that includes decision-making and energy management features. The HEART toolkit thus becomes the heart of a building, regulating its energy consumption and energy flow.
In terms of renovation, the HEART system will be tested on demo buildings managed by social housing providers, such as Est Métropole Habitat, a social housing organisation managing 16,000 social housing units in eastern Lyon, France. A second test site is owned by ACER (Azienda Casa Emilia-Romagna) Reggio Emilia, a public housing provider in Reggio Emilia, Italy. Over the next two years, after the HEART interventions, the buildings will be in line with NZEB levels of energy consumption (<50 kWh/m2/yr) – and should achieve energy savings of 90%.
The Norwegian demo case of the H2020 project 4RinEU showed the importance of the replication potential that can be presumed in the following steps: survey, digital measurement, and the creation of a 3D model. All this data can be read directly into the CAD/CAM software on site and generated in a 3D model or recorded by a surveyor.
The workflow of the prefabricated façade approach fits the planning within the BIM (Building Information Model); after the manufacturing and assembling, modules are ready for being transported to the building site. Here, modules will be installed and anchored to the existing building with the use of cranes and/or scaffolding. Final operations are required to connect electrical components or other integrated technologies.
Credits: 4RinEU project
Another interesting approach to prefabricated systems is the P2ENDURE project that combines 3D printing, laser and thermal scanning and Building Information Modeling to enable the production and installation of prefabricated deep renovation systems. The global aim of this project is to improve the availability and performance of energy saving solutions for deep renovation and to demonstrate their performance with the transformation of vacant, obsolete or sub-optimal public buildings into highly energy efficient dwellings with a low environmental impact.
The promoted solutions are SME-driven and geared to rapid and low-disturbance on-site assembly processes for deep renovation. The project provides a number of affordable Plug and Play prefabricated solutions for the deep renovation of building envelopes and technical systems , which are ready to implement, 50% faster from production to on-site assembly, and scalable and adaptable to different building typologies and different climatic zones in Europe.
Europe is moving forward quickly and the innovative solutions proposed by the European projects, including others such as RenoZEB are being complemented with proof-of-performance, which will provide the evidence that the path of prefabricated integrated kits is a viable solution for the Renovation Wave for Europe with the objective of doubling the annual energy renovation rate of residential and non-residential buildings by 2030 and to foster deep energy renovations.