Building waste accounts for over half of all waste generated in Ireland and it is the fastest growth waste stream in the European Union. In 2022, 8.3 million tonnes of construction waste was produced here. And while the vast majority of these waste materials are excavated soil and stone (about 85 per cent), this also includes concrete, brick, tiles, glass, metal, plastic and wood.
It is estimated that only about 8 per cent of building waste materials are recycled here compared to up to 90 per cent recycling rates of certain construction materials in some other European countries. However, recycling is now considered lower down on the waste hierarchy compared to reuse when viewed through the lens of the circular economy, one of the European Commission’s strategic policies in the European Green Deal.
Circularity is not just about recycling. It requires a fundamental shift from the current linear economic model of take, make, use and dispose, according to specialists from the Irish Green Building Council (IGBC) who addressed a joint Oireachtas committee on the circular economy as it relates to the Construction sector in July.
Many construction materials are technically reusable but only 3 per cent of building materials are being reused in Ireland. Not only is this a significant waste of resources but it is also a missed opportunity to reduce costs and carbon emissions used to extract virgin materials.
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A United Nations environment programme report says 90 per cent of biodiversity loss is due to the extraction and processing of materials. And greenhouse gas emissions from material extraction, manufacturing of construction products, construction and renovation of buildings account for 60 per cent of emissions in the EU. Greater material efficiency could save 80 per cent of these emissions, the commission has noted.
The IGBC believes building and construction materials can be circular if they are designed to be shared, maintained, repaired, reused, remanufactured and — the least favourable option — recycled.
The Construction Sector Group produced a report entitled, Supporting the Circular Economy Transition in the Irish Construction Sector in April, 2024.
In his introduction to the document, David Browne, chairman of the Construction Sector Circular Economy Group said the sector is poised for transformation ... which promises greater productivity, new skills, reduced carbon footprint, support of circularity and expanded business opportunities. Reusing materials would also reduce costs and time wasted due to delays in the global supply chains for building materials.
However, the transition to the circular economy in construction in Ireland won’t be easy. The report found there is still a mindset of freely discarding materials at construction and demolition stages without assessing the quality of the materials. It also notes that there is little or no infrastructure (buildings, yards, depots) and an almost complete absence of takeback schemes in Ireland to collect, provide information on available stock, store and process materials and products for a circular construction economy.
Experts agree that creating markets for secondary materials will be key to change. However, there are some fears that reused materials and components may be unsafe due to wear and tear in their previous life.
Marion Jammet, head of policy and advocacy at the IGBC, says recertification will be required for reused materials. “They will need to be tested appropriately but we must reduce wastage and we also need infrastructure on building sites to separate materials.” The IGBC’s Construction Materials Exchange Platform is a digital pilot project which enables construction materials to be reused at their highest value.
Jammet acknowledges Ireland is behind some European countries in terms of circularity in the construction sector. “The revised Energy Performance of Buildings Directive (2024) will require the whole life carbon impact of buildings to be measured from 2028 but Denmark, the Netherlands, France and Finland already have legislation in place for this,” she adds.
Italy has made it mandatory for public buildings over a certain size to use secondary materials. Predemolition audits and 70 per cent recovery of construction and demolition waste are also mandatory in Italy as is minimum certified recycled content in all big construction materials/products and design for disassembly/deconstruction for 50 per cent of all materials used.
Meanwhile, predemolition audits and circular economy statements on resource efficiency and adaptability are required in larger buildings in London. In Ireland, there have been a small number of fine examples where materials have been reused.
These include: Baggot Plaza in Dublin where the concrete shell and core of the original building were retained; Miesian Plaza, also on Baggot St, where over 75 per cent of waste was diverted from landfill; and Opera Square in Limerick which had the largest pre-demolition audit to date in Ireland. But predemolition audits, waste management plans and even designs for disassembly are still rare here.
One thing is certain: Architects, engineers and builders will need training and upskilling before things will improve. “We need to change mindsets from a waste perception to a resources perception and increase awareness of high impact and high-value materials such as steel which can be reused,” Jammet says.
However, in spite of all these issues, there have been some moves towards circularity in the construction sector, led by the Environmental Protection Agency (EPA). Their new criteria on the recategorisation of some hithertofore waste materials to byproducts are a step-change for both the construction industry and the regulators.
Take, for example, the soil and stone which makes up a staggering 85 per cent of waste materials from new development sites (known as greenfield sites). These materials can now be removed as byproducts rather than waste materials and taken to another development site, rather than used as backfilling for quarries.
“Byproducts are in the top tier prevention in the waste hierarchy. Byproducts are never considered as waste,” says Caitríona Collins, senior inspector in the circular economy at the EPA.
Greenfield soil and stone refers to soil and stone from land that has not been previously developed and is not contaminated. Some soil and stone from so-called brownfield sites (where buildings are demolished before the site is redeveloped) can also be sent for reuse but only on a case-by-case basis following authorisation from the EPA.
The EPA has also developed new criteria for materials such as crushed concrete/broken concrete slabs (collectively known as recycled aggregates) which allow these materials to be sold by waste companies as a byproduct of the construction industry for use in the subbase of roads, greenways, car parks.
“These criteria streamline the reuse of these materials and bring more certainty to the industry. They also are about better resource management and supporting the circular economy,” Collins adds.
The landfill levy of €10 a tonne for construction and demolition waste introduced in September 2024 is to deter builders from using landfill. “We anticipate that the quantity of construction and demolition waste generated should drop in with these new criteria but it will take a couple of years to see the results in the statistics,” Collins says.
She does however remain concerned that until the reuse potential of all materials is optimised at the outset, the sector won’t fully move towards circularity. “The frailty is that there is no mandatory requirement for this to happen and no monitoring on the ground [site by site] of whether it is happening or not.”
She refers those in the sector to the EPA 2021 best practice guidelines for the preparation of resources and waste management plans for construction and demolition projects as a way forward.
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