I recently read the book Sustainable Materials, which describes the climate impact of steel and cement. Much of our decarbonisation efforts focus on energy efficiency and transport, with less attention given to industry. Analysing industrial CO2 shows that 19% of it can be attributed to cement production, and a whole quarter to steel, much of which is used in buildings.
There are a variety of ways to reduce these emissions. We can look for alternatives, though there’s little out there that can do what steel and concrete can do at the scales required. Reducing the amount of materials needed is another, finding ways to build lighter weight buildings. And another approach is to look at reusing building components, essentially recycling buildings.
We already recycle metal in many other ways, even whole ships. It’s harder to recycle it from construction sites because when a building is demolished, the waste is all mixed together. When steel rods have been used to reinforce concrete, it’s all bound together into very heavy rubbish.
But what if buildings were designed to be deconstructed, rather than demolished? They could be taken apart like a Lego set, and used to make something else. Any re-used concrete components would save the emissions from new cement being made. Reused metal components would steward metal reserves, and save the energy required to melt down and reform new metal elements. So how possible would it be to make a building this way?
Some buildings can already be taken down in sections and reused. Portal frame buildings – those big grey or green sheds widely used in industrial and agricultural settings – those can be dismantled with relative ease. Portal Power is a company that specialises in this. Give them a call, and they’ll come and take down your old building, refurbish the steel, and sell it on to someone else as a secondhand building.
We do it with bricks too, sometimes. Old bricks can be useful for renovation work or extensions where the owner wants the new brickwork to match the old, and there’s a healthy market for reclaimed or ‘vintage’ bricks. Sometimes a part of the country has a locally distinctive brick that is no longer easy to find, such as Cambridge Whites or our very own Luton Greys – or in the US, Old Chicago bricks or Milwaukee Cream. Where there is demand for these, it is worth the time and effort to take an old brick building down carefully, rather than swinging the wrecking balls.
The authors of Sustainable Materials believe that deconstruction and refurbishment of building materials shouldn’t be as rare and specialist as they are and present a great business opportunity. But it won’t always make sense, so it’s not something that can be universally applied. Sometimes it just takes too long on site – deconstruction is 3 to 6 times longer than demolition, and many developers won’t want to wait that long. Other times the building just isn’t suitable. It wasn’t built to be taken apart.
That’s something we can begin to change. Looking to the future, there’s no reason why more buildings couldn’t be drawn up with deconstruction in mind when they reach the end of their lifespan. Occasionally they are – the original plan for London’s Olympic stadium was pack it down into a much smaller venue after the event, and it was designed with that in mind. They decided to keep it.
As part of its Plan A commitments, retail chain Marks & Spencer have also looked into design for deconstruction in the development of new stores. A new store at Cheshire Oaks demonstrates a number of techniques, including modular walls, and timber held together with large bolts for easy disassembly. Like Maersk’s ships, it also comes with a full end of life guide that a future deconstruction team could follow, showing what has been used where and how it can be safely recycled.
Another building planned for the end of its life is Hayesfield Girls School near Bath. It is expected to last for 50 years, and uses modular straw-bale walls. The timber can be taken apart without damaging it so it can be reused, and the straw is untreated so that it can be composted.
As we move towards a circular economy, more building will be planned this way and design for deconstruction will become more common. Deconstruction manuals could become standard. The result would be a healthy market for recycled building materials, lower carbon buildings, and zero-waste to landfill construction sites.