DESIGN PROCESS: Manufacturing and Construction: Digital Craftsmanship and The Renaissance of Three-dimensional Design Communication

Three-dimensional design has transformed the architect’s ability to communicate and has had an equally profound impact on the manufacturing and construction process. Here Rob Cullen assesses the façade design and delivery process for three exemplar residential projects to address what defines manufacture of building components in the 21st century, and how this impacts the role of the architect.

Within the 2020 RIBA plan of work, Stage 5 is identified as ‘Manufacturing and Construction’. As recently as the 2013 edition, Stage 5 was previously identified as construction alone1.

In antiquity, the appearance of the facades of buildings were resultant from the building construction technique, so the face material of the buildings provided structural integrity as well as the building aesthetic. During the renaissance, facades and their backings began to separate, the outer skin of a building was ornately crafted from expensive materials, with a structural base backing material behind this outer skin formed from the building construction.

Renaissance architects worked in three dimensions, preparing scaled timber models of their designs for builders and craftsman to scale from in order to form the base construction of the building. These then introduced sculpted components to create the façade, created independently of the main construction work.

Modern construction has taken further steps towards divorcing the external cladding of a building from the structure of a wall which provides the building’s enclosure.

Until fairly recently, architects have produced constructional information predominantly in two dimensions, but now, with three-dimensional modelling becoming mainstream, the architect has now gained the ability to digitally model and craft buildings as a prototyping process.

The RIBA plan of works 2020 edition acknowledges this evolution in our way of working by the acknowledgement of the manufacture of building components in Stage 5 to accompany construction. So what defines manufacture of building components in the twenty first century? And how does this impact the role of the twenty first century architect?

In order to answer these questions, we assess the façade design and delivery process for three exemplar residential projects, all of which are conceived to be striking stone clad buildings: Bath Riverside Buildings B5 & B16, Building D Royal Exchange Kingston and Building H1 Chelsea Creek.

The commonality shared between the three projects is that firstly, they are all conceived by three of the UK’s leading architects, secondly they feature stunning, innovate, crafted facades and thirdly, Scott Brownrigg’s Design Delivery Unit either have delivered or are in the process of delivering all three projects.

The manufacture of building components has evolved with the evolution of building production facilities advancement in mechanisation and transportation have allowed for larger parts of buildings to be manufactured, items have become larger and more complicated.

In recent times, with the emergence of ‘digital craftsmanship’ facilitated by the use of structurally intelligent 3D software and BIM Technologies it is now possible for the complex and innovative projects to be delivered.

VIRTUAL STONEMASONARY

Some building components, such as curved brick specials and reconstituted stone components can be made in moulds, but how do the mould makers for such components know how to create the precise geometries that today’s designs require? Our first project example, Buildings B5 and B16, conceived by Studio Egret West, can be described as the ‘Wedding Cake’ buildings, and can be described as organically formed pavilion buildings clad in Bath stone with undulating facades which step in as the buildings are taller.

“The complexity of the design and bespoke scheme was enthralling, the design of both unique buildings captured ones attention due to the high level of complexity and detail with both the façade and internal design. The use of BIM software was the key attribute to the success of both these schemes, to facilitate 3d modelling, the complexity with the shape, material connectivity and sub contractor checking.”

Phillip Roy, Design Delivery Unit, Architect

The façades of these buildings are constructed with a Structural Framing System SFS inner leaf encasing a reinforced concrete frame. The external cladding is reconstituted Bath stone with undulating geometries. The buildings were modelled using 3D BIM Software to establish the line of this encasement so subcontractors could design this system. The components of the stone cladding system which was faced the SFS were crafted digitally and virtually prototyped so that precise moulds could be made by fabricators.

This project is an example of how the role of the architect has evolved to include digitally making the building components and to leading and informing the process of manufacturing the façade components.

The stone fabricators utilised the three dimensional design drawings to create moulds, and the external cladding of the building was manufactured so that it could be transported to site. The architect’s role also included the co-ordination of the subcontractor’s drawings of the components back into the design. It is however worth noting that the final finishing of the stone was undertaken on site via a sanding process carried out by stonemasons.

'CRAFTING PRE CAST CONCRETE’

Prefabrication and offsite manufacturing of entire facades of buildings can be considered to be a well-established construction method in the UK; however the technology for pre-casting such panels were limited by project budgets, the design of the components and the skills of the mould makers.

Pre-cast concrete cladding technology is still utilised today, benefitting from up-front input from architects which is brought about by the symbiosis of an understanding of the technology and the ability to digitally model the forms of the moulds required to manufacture pre-cast concrete elements. Consequently, the resultant buildings delivered are be far more varied in form and geometry than their pre-cast clad predecessors.

Building D, Royal Exchange Kingston is one such example. Conceived by renowned architectural designer Simon Bowden, this fourteen storey building is elliptical in plan, and is clad in an insulated pre-cast panelised system. The design features fluted panels which include compound curves arranged around the plan form. Whilst the technology to fabricate such panels has been in existence since the 1960s, the cost of doing so could be quite owing to the skills involved in making the moulding for each panel.

“The use of 3D modelling on this project has enabled us to resolve complex junctions of the desired profile where the vertical meets the curving horizontals, and to marshal the decorative features within the profiles both visually, and pragmatically to ensure panel jointing and sealing is fully controlled. It also assists with 3D hygrothermal analysis of the façade to prove the proposals, as well as assisting in much more detailed sequencing analysis, to clearly show the interaction of the pre-cast panel system with the prefabricated glazing system, step by step to assist with a successful site installation.” Technical Director, Barry Clarke

In order to deliver this elegant and complicated design for this project the designers (first the architects and then the subcontractors) were required to make the panels digitally. Digitally crafting the panels enables mould makers to understand and create the formwork to facilitate the construction of the panels and the sequencing of their installation. The panels are to be fabricated offsite and brought to site for installation. Combining this with an offsite pre[1]fabricated glazing system allows for an efficient encapsulation of the basic building frame.

The up-front digital design process is similar to that deployed in the virtual fabrication of the stone cladding at Bath Riverside, however the construction of the system differs because the cladding panels are fixed back to a secondary streel structure attached to the buildings re-in forced concrete frame.

The architect’s role in designing a cladding system of this nature extends further – to include full up front co-ordination exercise between all of the other trades involved in the construction of the façade to ensure statutory approvals are acquired. This process also requires considerable input from the design team; including structural engineers, façade consultants and the project fire engineer in order to ensure that the crafted components can be successfully integrated into the façade of the building.

One of the challenges faced when designing an insulated precast panelised system is the coordination of the fire[1]stopping, waterproofing and vapour control at the system supports, its positioning with respect to the building frame and the interdependence with other components.

Offsite manufacture will provide a confidence in the precision of the reinforced concrete elements and their interfaces with the other key façade elements. Confidence in the installation can be accrued by the fact that the designers have co-ordinated the components by constructing the building virtually.

THE VIRTUAL CRAFTING AND ASSEMBLY OF CLADDING SYSTEMS

Chelsea Creek Building H1, is a 30 storey tower which is clad in glistening, white Portland Stone coloured cladding. The concept architect, Squire and Partners vision for Building H1 is for a building with clean lines and a sharp aesthetic. This design features geometrically formed façade components which undulate in plan, and also in elevation.

If such a façade were to be traditionally crafted and constructed, then stonework could have provided a way to construct it; however this would not be financially viable in today’s world.

The cladding systems used in Building D, Royal Exchange might give a satisfactory aesthetic however, a pre-cast concrete cladding system could be too heavy to be applied to such a tall building without major structural enhancements.

The manufacture of building components can extend to include entire façade systems; which combine multiple building components and a lighter weight approach to construction.

“It’s all about modularity, instead of creating and detailing a single façade, we had to digitally create in the region of 50 different modular components featuring a structural frame, insulation, doors and windows, fixings, fire stopping and external cladding.”

Witek Mysliweic, Design Delivery Unit, Architect

In order to design such a façade, the architect needs to understand how systems are manufactured. Proprietary systems are selected as the basis of the design and the modular façade components are then integrated with these systems.

Every part of a complex façade requires consideration, from the glass reinforced concrete outer cladding layer, to the unitised ‘stick system’ structural frame and its fixings to a buildings superstructure, the insulated infill panels which fit between the stick system and the glazing of window and door units.

Fire stopping in a unitised system is, as within any façade, of paramount importance. Factory assembly of the units affords the opportunity for the installation of fire stopping products and the certification of the fire stopping to take place under factory conditions. The interfaces between the GRC and the unitised structure of the panels are very carefully considered and along with the project fire engineer, the architect plays an important role in using reasonable skill and care in the specification and detailing of the appropriate fire stopping products to be part of the unitised system.

The co-ordination of windows and doors takes place ‘up front’, these components are integral to the structural frame system.

In designing this type of façade system, the architect is responsible for a significant part of the up-front design of the system by digitally making the bespoke elements of the cladding, the GRC outer skin of the building and co-ordinating them with the remainder of the façade system. This process is informed with the input of the project consultant team including façade consultant, structural engineer, project fire engineer, and also requires input from other façade specialists and manufacturers.

The precision in the employer’s requirements afforded by the modelling of the building will provide the contractors delivering the unitised façade to deliver against the vision set out by the concept for this building.

The role of the architect has evolved so that we now digitally make bespoke components in order to ensure that the visual aspiration of the design concepts are met, and that the buildings can be delivered on budget.

We are just about getting to the point of having 3D information to build from. As the early renaissance, the architect would have built a scale wooden model of a building. Builders would take the model, scale it up and then deliver full scale versions of it. We have seen how current construction methods have been affected by the architect’s regained ability to communicate increasingly more complicated and intricate detailed design and construction information in three dimensions.

Front end design input is of paramount importance in informing the manufacturing process, as is a control over the interfaces between different products. The role of architect as digital craftsperson overseeing the manufacture of building components is very exciting and is evolving rapidly.

It is right that the RIBA has acknowledged manufacture in Stage 5. Perhaps there might be a nod to digital crafting in future iterations of the RIBA plan of work. Particularly because digital technology has led to a rapid resurgence of three dimensional detailed design communication and illustration which allows buildings to be truly conceived and delivered in three dimensions.

Further technological developments in three-dimensional printing and future material developments will only serve to give the architect ever more influence over the art of the possible in façade design. These innovations will deliver some very exciting times for façade design.

1. RIBA. 2020. 2020 RIBA Plan of Work. RIBA