CA18 - The Hidden Power of Old Buildings

Why celebrating old things is key to lowering carbon.

THE TOPIC - ADAPTIVE REUSE

A few weeks ago I posted about the importance of old things.

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A similar idea can be true of architecture but with a very significant caveat.

Performance.

Simply put, old buildings generally don’t perform very well, so what is the point in keeping them around? Are you better off tearing them down and building something new and higher performing? Well that all depends on where you live, what the building is made of, and the project budget. It’s a complex equation as you may have guessed.

From a carbon point of view, this debate comes right back to the balance between embodied and operational carbon. If you have a focus on embodied carbon, retaining the existing building will be the most important factor BUT if you focus on operational carbon, a new building will perform better. The existing building may be an energy pig, but building new will require significant embodied carbon. What we really need to be focussing on is whole-life carbon which typically favours adaptive reuse.

Fundamentally it’s not a simple question, but one we need to consider with carbon at the centre.

If you want to read about more topics that hing on this idea of operational vs embodied carbon, checkout some of the past articles - Passive Problem, Insulation Paradox, Upfront Emissions, Early Stage Carbon.

Adaptive reuse as a carbon reduction strategy is made difficult by the flashy images of new buildings plastered over our magazines, websites, and marketing paraphernalia. These buildings, although high(er) performance than their predecessors often come at the expanse of demolished buildings that still have value. One of the things architects can do to help change this narrative is to celebrate buildings that involve significant renovation and re-use. Too often buildings that fall into this category are skipped over when the marketing team is selecting projects to highlight.

Take for example the Quay Quarter Tower recently completed by 3xn in Sydney. The building is estimated to have saved over 12,000 tonnes of CO2e by reusing 65% of the existing concrete building structure and 95% of the core. The amazing thing is this 1976 building is far from small. It stretches over 49 stories and sits in a prominent space on the harbor. It is considered the world's first tower transformation.

We need to do a better job highlighting these projects for the world to see and encouraging our clients to consider reuse and adaption rather than assuming a new building is THE solution.

THE GRAPHIC

WHY IT MATTERS

Adaptive Reuse matters for three primary reasons:

1. Structure has the highest embodied carbon impact

2. Ability to reduce energy use

3. Creates an economy of salvage

Let’s dig a little deeper:

1 - Structure has the highest embodied carbon impact

The structural system in a building is known to the highest embodied carbon emitter. By saving this critical part of a building the embodied impact of your projects can be much lower than an equivalent replacement. Not to mention all of the waste that is generated when a building is demolished.

2 - Ability to reduce carbon intensity

Adaptive reuse projects offer a great opportunity to reduce carbon intensity by increasing performance through air tightness and higher insulation levels but also by implementing lower carbon heating and cooling methods through electric mechanical systems. Combine this with your embodied carbon benefits and you have a winning scenario.

3 - Creates an economy of salvage

One of the most difficult things about designing sustainable buildings is the building industry is designed around a disposal model where things are used and then thrown away. As more and more projects embrace adaptive reuse, a stronger economy of reuse will develop making it easier and easier to design projects that reuse key components.

1 ARTICLE TO READ

Check out these 5 Tips To Design Better Buildings. Architect Keith Hempel lays out 5 key ways their firm has been able to meet the 2030 commitment. They are simple but very very effective.

Also, an interesting read titled Retrofit First, Not Retrofit Only by Steve Gilchrist. With 5 recommendations for owners and policymakers. If you’re interested he also has a great newsletter.

1 PERSON TO FOLLOW

Duncan Baker Brown is one of the OG’s of Carbon IMO. He is the founder of BakerBrown Architects and is also the author of the book “The Re-Use Atlas: a Designers guide Towards a circular economy”. Well worth the follow.

1 RESOURCE TO ACT ON

The CARE Tool was created for exactly the scenario outlined above. Understanding the carbon impacts of a new construction vs renovation is critical, especially at the early stages of a project. I’ll be writing a more detailed review of CARE in the future, but for today it’s a great resource.