Modular housing is revolutionising how buildings are designed, fabricated and assembled. The term refers to homes whose constituent parts are predominantly built in a factory and simply assembled on-site. Given that it is speedy, sustainable and long lasting, it has the potential to resolve the housing stock shortage.
If you’ve ever seen the Huf Haus examples on TV’s Grand Designs, you’ll know how beautiful and architecturally interesting they can be, a world away from the prefab buildings some of us went to school in.
They’re also well proven. Not alone is German company Huf Haus itself more than a century old, but in Sweden, according to a 2017 report from University of California Berkeley’s Terner Centre for Housing Innovation, off-site building techniques already account for more than 80 per cent of new single-family homes.
Typically, modular housing comes in two forms. With 3D volumetric, modules leave the factory as three-dimensional structures with floor, walls ceiling, internal connections and finishes already formed. With 2D construction, panels are built in a factory and then flat packed and brought to the site for assembly.
Remagin, part of the Etex building materials group, specialises in 2D steel frame panels that come out of the factory with insulation, air tightness membranes and even cladding already formed. These are flat packed on to a trailer, ready to be slotted together on-site.
The appeal of the 2D modular system is the flexibility it gives architects to design all sorts of shapes and sizes. “It doesn’t have to look like a square box or conform to certain dimensions; it’s very flexible – 2D modular can be any shape or layout,” explains Darragh Ryan, head of commercial – Ireland at Remagin.
Two-dimensional modular construction is also highly cost effective, particularly for buildings such as apartment blocks, he adds.
“With 3D volumetric, if you’ve got a multistorey building, every module you lift in has to have a ceiling, while the next panel above has a floor, so you are doubling up on structure,” says Ryan. Three-dimensional modular units may also contain hidden cavities and so need additional fire-stopping measures; it’s easier to ensure building regulation compliance with 2D panelling, he explains.
But the real advantage that Remagin’s modular building methods offer is economies of scale – so, the larger the project, the better.
“It’s not so much for a one-off house in the countryside as it is for an estate, with maybe five or 10 of the same houses being built, because you model and design it once, and then have all the panels made in our factory, similar to a production line in the car industry,” says Ryan.
Remagin was selected by OBR Group to provide the complete superstructure for Cork City Council’s housing scheme at Ardrostig. To assist first-time buyers to enter the market, 35 of the development’s total of 65 homes were designated as affordable housing.
The homes were A rated for energy efficiency, with underfloor heating and high levels of attic insulation. The company delivered the light gauge steel superstructure, including a mix of two- and three-storey apartment blocks, two duplexes and 40 houses, consisting of a range of floor and roof types, designed, manufactured and installed on-site by Remagin, having been delivered from its factory in Cahir, Co Tipperary.
Such building methods don’t just get people into homes quicker. The sustainability benefits are clear too, says Ryan. Given that the built environment accounts for 37 per cent of Ireland’s emissions – a figure due to be halved by 2030 – that’s good.
Remagin’s light gauge steel framing (LGSF) systems not only offer a lower-emission solution, with fewer vehicle movements required to and from site, but also create safer and more efficient sites, with fewer transport movements on site.
As the solutions are made in controlled factory conditions, waste is minimised, with the accurate pre-assembly of the product virtually eliminating site waste.
A report from the National Economic and Social Council (NESC), which advises the Government on strategic policy issues relating to sustainable economic, social and environmental development, identifies the opportunity that modern methods of construction (MMC) such as modular offer to help boost Ireland’s new housing supply, while at the same time helping to meet climate targets and improve circularity.
“Steel is almost 100 per cent recyclable,” says Ryan.
The report shows there is scope to use the Government’s Capital Works Management Framework and procurement process to drive greater housing-market adoption of MMC and argues for an increase in the targets and funding for new public housing using MMC under an expanded Social Housing Accelerated Delivery Programme.
The report also examines finance and recommends the creation of a dedicated forward-funding arrangement for MMC in housing that would leverage increased investment in off-site manufacturing for MMC in housing.
Finance is an issue, as modular construction models require substantial upfront investment rather than the traditional construction industry model of staged payments made on reaching fixed milestones.
Solving that issue could prove transformational. Speaking at the launch of the report, Dr Dáithí Downey, policy analyst at NESC said “Ireland can produce many new social and affordable homes using MMC that meet the diverse needs of all generations and create communities that are great places to live.”
He also argued that “we must invest more to boost new public housing using MMC”, and noted how “this investment will address the supply deficit and meet our housing needs, help grow our industrial and manufacturing sector in MMC for housing and underpin efforts to meet the goal of decarbonising our housing system”.
