Manuel dos Anjos, FMDC Ltd
In July, Stone Federation hosted the first Stone Symposium: The Case for Stone, which gathered over 100 architects, designers, structural engineers, clients and stone suppliers.
One of the speakers was Manuel dos Anjos, Senior Façade Engineer at London-based design consultancy, FMDC Ltd.Manuel spoke as part of the ‘Delivering a Low Carbon Built Environment Using Stone’ session, and following his seminar, we spoke with him to find about more about his take on the subject.
1) What were some of the highlights of your discussion, how do you think the panel format helped to push discussion further?
Although, at high-level, the benefits of using structural stone on the façade to reduce the embodied carbon of mid-rise commercial buildings in the city appears to be an obvious solution, there are implications and challenges that need to be looked at carefully, as some of the performance targets that are commonly achievable with conventional façade types would become challenging.
Our panel was made up of an architect, a stone specialist contractor, and a façade engineer, which was arranged in a way that the topics would compliment each other.Peter Fisher, from Bennetts Associates, introduced various concepts and big-picture drivers that are shaping the current climate to deliver lower embodied carbon facades. Mark Waldren and Ryno Nel, from Szerelmey, showed various complex precedents where stone was used structurally and could enable the implementation of structural stone on a bigger scale. Lastly, in my façade engineer role, I provided our vision on how a structural stone façade could be achieved in a mid-rise commercial job that could meet the performance targets typically required today. 
2) What are some barriers you think stand in the way of a carbon-free future, how can you see these being overcome?
On façades, the challenge is to strike a balance between buildability, programme, performance, and cost. Often, the lowest embodied carbon façade that meets ambitious thermal performance targets is one that’s fully site-built, takes longer to build, and increases the risk for site defects. Using structural stone as an example, it requires early coordination between the structural and façade contractors, as both would need to be erected in parallel, something that wouldn’t typically happen on non-loadbearing facades.
3) How important is embracing stone to achieve a sustainable, green built environment?
It’s important to keep in mind that there is no silver bullet when it comes to sustainability, all jobs should be looked at on a case-by-case basis. Stone provides a low-carbon and long-lasting cladding and structural solution that should be part of the options for jobs that truly aspire to help build a net-zero carbon future. The biggest challenge when using stone as a cladding however is that, due to its heavy weight, there is often an increase in the perimeter structure which is made from carbon intensive materials, such as concrete or steel, that could negate the benefits of the stone itself. This is why the case for using the stone as a structural element is compelling.
4) When comparing stone to other building materials, what are some of its advantages when working towards environmentally friendly construction?
Stone is a naturally formed product that only incurs on carbon emissions due to the extraction, fabrication and transportation involved. It provides an option to locally-source materials, which further reduces the carbon emissions due to transportation. A point about stone that is often overlooked, and most carbon emission numbers do not consider, is the wastage rate during cutting and selection.
One benefit of working with stone is that it helps with circularity as it allows for recycling and repurposing. On 81 Newgate Street, we repurposed the existing handset stone panels and casted them onto precast concrete panels which are being installed on the new building. This is essentially using ‘spoila’, which is stone taken from an old structure and repurposed for new construction or decorative purposes.
5) How was your experience at the symposium? How do events like this help to bring together the industry and promote collaboration?
It was a well attended and organised event, with different players along the design and construction stages which is key to foster those moments that bring new ideas that challenge conventional forms of thinking.
