Facade retention
Facade retention (or facadism) involves supporting existing façades or party walls for renovation and is often used for works to listed buildings. By retaining the façade, the overall look of a building is preserved while new internal floor structures and layouts can be constructed to meet the needs of modern occupants.
A shoring retention scheme is generally required to support the front façade while construction of the new internal layout takes place. Once construction of the internal structure is complete, the existing façade can be connected to it.
The temporary works involved in façade retention can be significant structures in their own right and play a major role in assessing the financial viability of a project. From the outset, the design team should address the importance of the retention as a critical element of the project and careful feasibility studies should be carried out to to assess its viability and likely costs.
A thorough understanding of the existing building is vital including its age, the overall structural form, the structure of neighbouring properties, details of connections between the façade and the existing internal structure and existing foundation sizes. Site constraints (such as available space) may also affect the location and design of the temporary works.
Types of retention include:
- Scaffolding, suitable for low level facades between 3 and 4 storeys, with sufficient space at their base for installation.
- Proprietary retention, involving props, ties and bracing suitable for higher facades as the general quantity of components are reduced.
- Fabricated steelwork, used when cost of hiring proprietary equipment over long periods of time outweigh the cost of fabricating a structure
- Combinations of fabricated and proprietary retention systems.
The support system must be stiff enough to prevent excessive movement, which could cause cracking to the façade. By pre-loading the façade with a series of flat jacks the likelihood of movement can be reduced and deflection limited. The overall stability of the system must be maintained in all directions taking into consideration wind loads and impact loads. The system must also resist the overturning moment as well as moments generated by eccentric dead load. Kentledges can be incorporated into the design to counteract these moments.
The process is criticised by conservationists as creating disembodied facades propped up with scaffolding like a film set or dominated by grotesque new developments, largely just to get around conservation area or listed building restrictions and to avoid paying VAT. PPG15 specifically condemned preserving facades while gutting and reconstructing interiors. For more information see: The Creeping Plague of Ghastly Facadism.
[edit] Related articles on Designing Buildings Wiki
- Conservation.
- Crane supports.
- Deleterious materials.
- Demolition.
- Façade.
- Falsework.
- Formwork.
- Refurbishment.
- Renovation.
- Scaffolding.
- Shoring.
- Temporary works.
- The Creeping Plague of Ghastly Facadism.
[edit] External references
- BS5975:2008 + A1: 2001 Code of Practice for Temporary Works Procedures and the Permissible Stress Design of Falsework (BSI 2011).
Featured articles and news
Finalists for 2024 CIOB Awards revealed
80 construction leaders and companies from across the UK.
Health and Safety Training for Construction Employers
A brief run through essential training tips from a user.
3D Laser Scanning in Building Construction
A comprehensive guide from a Cohesive BIM wiki user.
BIM for structural reinforcement modelling
From the basics to the future from our Cohesive BIM wiki.
ECA skills recharge at the House of Commons
As electrical sector feels skills shortage bite.
The impact of pandemic and new legislation on courses
CIOB Academy’s course take-up inked to external factors.
An artist, philanthropist and ex-Army helicopter pilot
Q and A with self-representing artist, Hannah Shergold.
Building Safety Regulator appoints permanent director
And publishes three-year strategic plan.
Update on the Energy Savings Opportunity Scheme (ESOS)
Introducing changes to make it more effective from 2024.
2023 CIOB photography competition
Shortlist announced for 2023 public choice award vote.
The last of the Victorians. Book review.
Grimsby's Kasbah: where’s that?
An exotic name that is shrouded in mystery.
This weeks guest editor, Ankita Dwivedi of Firstplanit.
Fropm practice to research and the business of materials.
Terms, histories, theories and practices.
Types of work to existing buildings - repurposing of buildings
Alteration and everything else before demolition.