Raj Somal of engineering consultancy Dice looks at the exemplar Positive Homes modular development, explaining how modern methods can produce much-needed housing quickly on a tight budget, as the country begins to navigate life post-pandemic.
There is no questioning the efficiency and benefits of modular construction, especially now as we begin forging a new path out of the pandemic and attempt to address the ongoing housing crisis.
We are also looking to find a more sustainable way of living, which begins with the materials and methods our homes are built with. There is a definite outdated stigma attached to MMC that comes down to misunderstanding as well as a reluctance to changes from tradition.
Modular homes are now able to balance affordability with quality and design, and can be created offsite, freeing up further cash and time. This was the case for our residential project with Positive Homes, which saw Homes England invest £750,000 into the project via its Home Building Fund – marking the first time the public body has financially supported an MMC residential scheme by a small developer.
Good for purse & planet
A huge reason to champion modular homes is the energy efficient nature of the properties and the build, as well as the ability to save time and money for developers. The nine modular homes within the Positive Homes development, for example, were built in a world-class factory by ilke homes, before being ‘installed’ in just five days, with water and electricity services connected just two days later.
The cost savings don’t begin and end with the developers either. They’re also much more cost efficient for residents. The Positive Homes development is a truly sustainable one, and is renowned for having only ‘£1 a day’ running costs. Outperforming almost every other housing development in the UK, it truly showcases the ecological benefits of MMC. All homes on this site have an ‘A’ rated Energy Performance Certificate (EPC). To do this cost effectively, there is no other practical build method other than offsite construction.
Our involvement in this project also contributed to meeting the energy efficiency targets of the scheme. The developer had already managed to halve the amount of concrete (a major generator of CO2) used in the foundations compared to a typical new house. But in addition, Dice incorporated carbon neutral geo-cellular storage for the attenuation features, which formed part of the surface water drainage design.
With MMC, budgets are much easier to meet due to fixed price contracts. The cost of homes is known from the beginning, ensuring there are no nasty surprises along the way. There is increased site safety and schedule certainty due to the controlled nature of the production environment.
This also helps reduce material waste, and there are fewer delays. Furthermore, by only having one contractor on site at once – the groundworks team, followed by the home installation team – schemes are far easier to manage than a conventional build, where multiple trades need to work ‘on top of each other.’
Benefiting the community landscape
Another challenge when building new homes is ensuring they suit the local landscape, so the ability to adapt modular homes to integrate with the community is another plus. The Positive Homes site used in Nottinghamshire was former NHS land that enabled a return of £250,000 to the county’s mental health trust, reinvesting in vital services.
The homes were given low pitched roofs to reduce the impact on pre-existing properties’ view and the 50 metre long driveway was enhanced with raised planters made from upcycled pallets, as well as trees and shrubs to attract wildlife. Developer ilke Homes and its suppliers Metrotile were also able to tile to accommodate bat boxes after some were discovered to be nesting in a nearby demolished building. Modular homes can be built to accommodate the environments they are being added to, rather than taking away from them.
Not all beneficial elements are visible to the naked eye either, such as sustainable drainage systems (SuDS). Incorporating this into the scheme not only complied with the requirements set out by the Lead Local Flood Authority (LLFA) in terms of surface water treatment, but also met the developer’s requests to deliver an engineered solution that minimised embodied carbon.
The team specified an innovative eco-friendly geo-cellular storage system, which is made entirely from a soy-based resin and recycled aggregate, making this a truly carbon-neutral alternative to traditional attenuation features.
This development proves that building homes to very high environmental standards is more than just possible – it can quickly become the norm. This is vital if we’re going to meet the ambitious housing targets as well as net zero carbon targets, as we emerge from the pandemic.