Dublin and Manchester-based Harcourt Architects has completed a council housing scheme in Dundalk, Ireland, using 3D construction printing the first project of its type in the world to meet internationally recognised technical standards.The system, with its rebar-free, load-bearing double-cavity concrete walls, allows schemes to be built significantly faster than conventional methods.The trio of three-bedroomed houses in Grange Close were completed in just 132 days. Developed and delivered with the practices emerging sister company Harcourt Technologies Ltd (HTL), the process shaved at least a third off the time required to construct the 330m project compared with traditional construction methods (estimated at about 200 days).AdvertisementUsing a COBOD 3D printer, each layer of concrete takes 18 minutes to cure before the next one can be added. The compressive strength of the walls is understood to be roughly five times stronger than traditional blockwork construction. The printer is operated by a team of three, and can print sections of wall up to 10m in height.The homes, which were built and funded by Louth County Council, have now received building control approval and comply with the rigorous ISO/ASTM 52939:2030 standard for additive construction. Each 110m unit cost about 205,000 to complete including traditional roof structures and standard internal and external finishes. But the team expects that price to reduce.Harcourt Architects three directors Justin Kinsella, Richard Mullin and Paul Kelly met while studying architecture at the University of Dundee. Their strong interest in construction technology and innovation led them to set up HTL in 2021.The three say they are already in discussions with both social housing providers and private developers in the UK to build more 3D homes and hope the completion of the Grange Close houses will act as the catalyst for scaling up the deployment of the technology.AdvertisementMeanwhile HTL, in partnership with Creagh Concrete, has been appointed to the Social Housing Emerging Disruptors (SHED 4) Framework, a 100 million initiative which aims to reduce costs and improve efficiency by connecting start-up, small and medium, voluntary and large scale innovators to public sector clients and social landlords.According to Mullin, the 3D-printed concrete currently saves roughly 20 per cent in embodied carbon compared with concrete block construction.The system uses locally sourced constituents in its ready-mix concrete and replaces ordinary Portland cement with locally available supplementary cementitious materials such as GGBS (ground granulated blast-furnace slag).The accuracy of the printing process greatly reduces waste, he says. The printer itself is modular and can be taken to site on a single lorry, in effect bringing the factory to site. This greatly reduces the number of deliveries to site, storage required on site and the carbon footprint associated with off-site facilities. The mass concrete walls provide exceptional air-tightness. Source:Harcourt Technologies Ltd2025-01-24Richard Waitecomment and share