environment Green Week 2021

Building greener pastures

From carbon dioxide emissions to waste and water use, the construction industry needs to look to a greener future. Izzy Rowley digs up the issues and investigates potential solutions
Image courtesy of SevenStorm via Pexels.com

Construction and buildings account for 36% of the world’s energy use, 39% of energy related carbon dioxide (CO2) emissions, and 33% of global water use and waste.

The ever-looming climate crisis means something’s gotta give – Ireland’s construction industry has to change, and it has to make that change affordable to the average person.

According to Francis Duffy, Green Party TD and spokesperson for housing, most of the homes now built in Ireland are highly-insulated and airtight ‘passive houses’, designed to use external elements like sunshine and shade to maintain a cosy climate and smaller carbon footprint.

Unfortunately, there is more to truly green construction –  the materials used have carbon footprints all of their own, and that’s where our attention needs to be.

“The big elephant in the room now is embodied carbon,” says Duffy.

“When you dig a hole in the ground and take material out of it, whether that’s steel, iron, or cement, it gets transported, processed, manufactured, and transported again to site.

“Then it lives a life on a site or in a building. It may be replaced or maintained, but at the end of its life, it’s transported again, disposed of, recycled, or upcycled.

“There’s energy and carbon involved in all of that, which means that a bit of material gains embodied carbon,” Duffy explains.

“We’re hitting around 900 kilograms per square meter of embodied carbon in our buildings, and an A-rated building is 300 kilograms per square meter,” he tells me.  

As an architect, Duffy is working on a private project in Dublin with the Irish Green Building Council. The aim is to use materials with low levels of embodied carbon.

“The big elephant in the room now is embodied carbon”

Francis Duffy

The frame of the building will be made from timber which “absorbs CO2 as opposed to spewing it out, which makes it CO2 negative”, says Duffy, who has extensively studied the use of timber as a sustainable material in construction.

“We’re using recycled bricks and lime mortar to hold them together. That makes the bricks easy to separate at the end of the building’s life, which means they can be used again,” he says.

Duffy believes this is the future of building.

“You’re looking at 80% of a building being designed and constructed with the idea that at the end of its lifespan you can take it apart and re-use a lot of it in another project,” he explains.  

Globally, efforts are being made to reduce the waste produced by building.

Cobod (construction of buildings on demand) are a construction technology company in Copenhagen, Denmark, who are pioneering 3D printed housing in Europe.

“We generate less waste [by 3D printing], because we have more precise numbers on how much material is needed for the building in advance,” says Vytautas Naslenas, a sales and marketing coordinator for Cobod.

However, Cobod print with concrete which Naslenas admits is not thought of as particularly sustainable.

“There are new solutions and companies are investigating how to make a mixture with a smaller CO2 footprint, but of course that is yet to come,” he says.

Affordability, speed, and how little waste is produced are the major draws to this method – by automating the process you make it quicker and reduce labour costs.

“I believe that in 15 years this will be the norm. Looking at how quickly things are moving from our side, it could be even sooner,” says Naslenas.

The cost of sustainable building is a huge issue – if construction emissions are so significant, as many people as possible need to be able to embrace sustainable construction methods.

“The housing regulations have improved significantly over the last number of years but they have made building really expensive,” says Michael Canney, chair of the board of Sustainable Projects Ireland.

“There’s a need to facilitate a more low-cost build without compromising on quality and energy efficiency,” Canney says.

Canney lives in the Cloughjordan Ecovillage, and Sustainable Projects Ireland work closely with the ecovillage.

An aerial view of Cloughjordan Ecovillage. Photograph by Eoin Campbell JustMultimedia.com

The ecovillage is 67 acres in total and divided into three parts: high-performance green homes, a community farm, and biodiverse woodlands.

The houses in the ecovillage are built “using local labour, local materials, recyclable and reclaimed materials” as much as possible, says Canney.

Cloughjordan is working hard to attract young people who are potentially earning less to their community.

“We’re in negotiations with a couple of housing associations to take a number of sites and develop them using an affordability model,” Canney explains. “And we’d be offering those at rates that acknowledge the need for affordable housing rather than the maximum yield we could get for them.”

“We are also looking at co-housing models where a number of people can come together and build a house cooperatively,” he says, explaining that people would choose DIY construction methods that allowed them to build themselves without the cost of employing skilled labour.

“There’s a need to facilitate a more low-cost build without compromising on quality and energy efficiency”

Michael Canney

Canney feels there’s a bigger issue lurking in the shadows here.

“So many people are really confused about these ideas of embodied carbon, recyclability, and what’s recyclable in real terms,” says Canney.

“I think people could do with some really clear guidance on this, because we are bombarded with greenwashing from manufacturers.

“There’s a real obligation on state and semi-state bodies to really inform the public in a very non-biased way about this, so people can really make informed decisions.”

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