By Peter Aramayo, Commercial Director.
It’s estimated that the National Heritage List for England (NHLE) contains details of around 500,000 listed buildings. Whilst these buildings are a stunning sight that represent our country’s history, maintaining their operational usefulness – often centuries after they were first built – can be difficult. That’s where façade retention comes in. Often used on listed buildings, it enables the overall look and feel of the building to be preserved, while the layout of the structure behind the perimeter is updated, or changed entirely to suit more modern demands.
The process of façade retention itself involves the propping up of a building’s front and side elevations, while demolition and construction work is carried out within the existing building. It can be a hugely complex process. As well as designing, engineering and installing the temporary steelwork, ensuring that all loads and deflections are accounted for, it is also important to continually monitor the structural integrity of the façade throughout construction. With a large percentage of listed buildings located within densely populated towns and cities, these busy urban locations can provide added challenges when considering a façade retention project.
When working on a façade retention project within a busy town or city, the boundaries of the construction site suddenly become far wider. As a result, careful consideration is required of, not just the building itself, but also adjacent structures, public footpaths, roads, transport links and live underground assets. Understandably, therefore, access becomes a significant issue, not only in terms of the design and placement of the steel framework but also from a practical and logistical perspective.
To minimise disruption to residents and businesses within the local area, designing a Temporary Works scheme with access in mind is vital. It is always important to avoid obstructing nearby walkways and roads; whether by designing the framework in a way that the steel props do not land on the pavement or by incorporating a portal into the framework, under which pedestrians can safely walk as normal.
Another aspect of access to consider on urban projects is from a logistical point of view; how you will physically get the required steelwork on to site. For example, you may be limited in terms of the size of transport vehicles available, depending on the roads surrounding the construction site. After all, city streets are not always suitable for large 44tonne capacity articulated vehicles. In the event that the vehicle size is restricted, you have to get smart about the framework design. Understanding how you can engineer the most efficient design can be invaluable. Whether that’s in terms of reducing the amount of steel needed, meaning fewer deliveries, or using lots of short pieces of steelwork, which can then be connected together on site to make one large steel prop or frame.
Once you have the steelwork on site, the challenges don’t stop there. Plant equipment is another important factor to consider, and one where limited site access can present a real headache. When large cranes are needed on site to help lift the steelwork into position, roads have to be closed, causing a significant knock-on effect on public transport and local businesses. At Mabey Hire, we are always looking to explore and develop installation options to help avoid this disruption, where possible. For example, some of our propping equipment is suitable for manual assembly. Or, as has been the case on some of our recent projects, the steel framework has been pre-assembled away from the main site before being transported to the location. It is then lifted into place during an overnight road closure, resulting in far less disruption and for a far shorter amount of time.
It is clear that our cities can provide construction and engineering teams with a real challenge. This can result in additional pressure being placed on engineering teams to not only design façade retention framework from a structural integrity point of view, but also from an access and logistical perspective.
As well as designing and supplying propping steelwork for façade retention projects, as part of our end-to-end services we also have a dedicated installation team on-hand. Not only does this leave you with one less thing to worry about, you can also be confident that design efficiencies and installation practicalities are always on our mind when approaching a temporary works project.