Currently, we are seeing the increase of offsite manufacturing revolutionising the way buildings are being built. Unitised facades are designed to exploit the benefits of building off-site and allow modern methods of construction to be applied to the external envelope. More specifiers, developers and contractors than ever before are recognising the benefits of moving elements of the construction process into a controlled factory environment. The build process can be speeded up, quality is improved and work on-site is significantly safer.
How the approach works
Unitised facades consist of prefabricated and assembled units which can be moved directly from the factory environment to the site for fast installation onto pre-prepared fixings. Typically, unitised facades are the width of a glazing bay and one or two storeys high and the panels are fully glazed and sealed off-site, with gaskets and glazing beads pre-installed in factory-controlled conditions instead of on-site.
The approach can be used for technically challenging projects, as well as fast track schemes, new build and refurbishment, and new designs can be developed for more complex and bespoke facades. Unitised facades do not dictate uniformity an infinite range of design variations is possible within the facade structure, with a mix of panel sizes, colours and materials.
Conventional cladding can also be eliminated because the unitised panels can hold stone and cedar, for example, as well as glass. This gives a single point of responsibility for the building envelope, which is easier to manage, and there are no difficult interfaces between different cladding systems.
So what are the advantages of this alternative solution to facade design and construction?
- Aesthetics – offer a wide variety of aesthetic variations allowing architects to use any combination of finishes, infills, external feature caps and glazing specification.
- Versatile designs including stone cladding, metal, composite or polycarbonate panels; windows, doors and fixed lighting glazing; brise soleil and photovoltaic panels
- Shorter lead times – help contractors and architects meet the increasing demand for shorter programme times and can achieve impressive reductions in time on site of up to 70% Increase safety on-site – units can be installed without the need to work at a height on scaffolding.
- Reduced storage and handling of materials on-site – a particular advantage in city centre sites where space and access are restricted.
- Precision engineered in a controlled production environment ensuring the quality of facade systems are significantly improved
- Less wastage – waste control measures are more stringent in a factory environment resulting in reduced costs from wastage, loss and damage.
Specification of pressure equalised rainscreen cladding systems
The use of a pressure equalised (or moderated) rainscreen cladding system is mainly chosen for buildings four to five storeys high, or over 12 meters. The main principle of a pressure equalised system is to balance the flow of air and control water using the building envelope.