Facade Retention – Part of the Enabling Works services we offer at Downwell
Facade retention is the supporting of an existing party wall or facade when a building is redeveloped. Primarily it is used with listed buildings and structures. Keeping the facade preserves the look of the building but allows the internal floor structures to be designed and built to modern standards.
Shoring retention is where the front facade is supported while construction of the internal layout is carried out. On completion, the original face can be connected to the new part of the building.
For obvious reasons, the temporary works used can be very complex and will affect the feasibility of the project. Designers have to carry out extensive feasibility studies to assess costs.
A thorough understanding of the existing building is critical, including its age, structure of neighbouring properties, structural form, connection details between the façade and the existing structure, plus existing foundation sizes. Site constraints will also affect the design and location of the temporary works.
Facade Retention types
- Scaffolding is suitable for low-level facades of between 3 – 4 storeys, with space at their base for installation.
- Proprietary retention involves ties, props, and bracing suitable for higher facades.
- Fabricated steelwork is used when the cost of hiring proprietary equipment over long lengths of time outweighing the cost of fabricating a structure.
- A mix of fabricated and proprietary retention systems.
Whatever the support system, it must be designed to prevent any excessive movement which would cause cracking to the facade. It is essential to preload the facade with multiple flat jacks, so any likelihood of movement is reduced. The stability of the overall system must be maintained in all directions to address impact and wind loads. The system will have to resist the overturning moment as well as moments caused by the eccentric dead load. Kentledges can be incorporated to counteract these moments.
Facade retention is often criticised by conservationists.
Downwell have vast experience of Demolition projects involving Facade Retention and will be happy to discuss to tender for projects involving these type of works.
Facade retention is the supporting of an existing party wall or facade