Off-Site Construction: Accelerating Zero-Carbon Housing

Decarbonisation is no longer an optional consideration for housing development projects — it is essential for securing a greener, more efficient future.

Despite efforts to shift away from our dependence on polluting fossil fuels to more renewable energy sources, the latest update to the UN Nationally Determined Contribution (NDC) Synthesis Report revealed that global greenhouse gas emissions are rising sharply. The report predicted a sizable 13.7% increase in emissions compared to 2010 levels by 2030 — a far cry from the reduction we need to mitigate irreversible environmental damage.

Residential energy use is one of the most rapidly growing areas of global energy consumption. As a result, developing more energy-efficient homes is crucial to meeting net-zero targets. However, there is a catch: traditional building methods contribute significantly to carbon emissions, with research attributing 11% of the world’s emissions to construction processes throughout building lifecycles.

So, what is the solution?

When it comes to decarbonising the housing sector, off-site or ‘modular’ manufacturing and sustainability go hand-in-hand. As well as minimising waste and building emissions, off-site construction presents many benefits for property developers, housing associations and councils — from reducing on-site costs to accelerating completion and returns on investment.

But how is a modular or off-site construction project delivered, and how does it help to create zero-carbon in operation homes?

Creating zero-carbon homes with modern construction methods

There are several benefits to building off-site compared to on-site in the modern world.

In traditional construction, architects complete initial designs before finding a contractor to start building, often leading to drawn-out timelines and revisions. Conventional building projects also require large numbers of on-site workers and have complex logistical needs associated with waste management, materials storage and weather-related delays.

Alternatively, modular construction champions a ‘fabric-first’ approach to design and building, producing part or fully finished 3D models in off-site factories, which are then connected on-site.

This methodology prioritises efficient and low-energy building as standard, using precision equipment to produce highly insulated and airtight structures to a standard that simply is not achievable in the field.

By optimising natural ventilation, thermal bridging and insulation before looking at post-construction additions, developers can supersede sustainable building regulations and guarantee that a home will be carbon neutral. For example, heat pumps are an excellent low-carbon heating solution but need electricity to run. So, combining them with solar panels is crucial to meeting zero-carbon targets.

Off-site building practices also ensure designs are nailed down before construction begins to minimise reworks, helping to cut costs and expedite the delivery of the project. By reducing labour requirements and on-site construction costs, modular construction offers significant savings overall — especially for larger schemes.

Although the upfront design costs associated with off-site construction are heavily loaded compared to traditional projects, knowing material and factory build costs and installation schedules ahead of time will ultimately pay dividends.

Plus, modular buildings are constructed with the future in mind. They can often be deconstructed and repurposed to suit changing community requirements, providing a win-win solution for councils and housing associations looking to decarbonise local residential assets.

Build smart through off-site construction partnerships 

Demand for off-site manufacturing is rising as modular construction practices demonstrate substantial cost, energy and time savings compared to traditional methods.

For the ultimate value-generating solution, housing developers can work with an architect specialising in off-site construction that can take on the role of both modern methods of construction (MMC) consultant and designer to streamline processes and drive collaboration.

One such MMC specialist is Modularize. Award-winning manufacturer NetZero Buildings engaged this off-site services provider as a consultant and designer for a collection of six all-electric family homes to rent in Sittingbourne, delivered by Public Sector Plc (PSP).

Mark Davis, Partnerships and Communications Director at PSP, said: ‘The UK not only has a crisis in the quantity of new affordable homes being developed, but it also has a crisis in the number of homes that are low energy in use. This is exacerbated by the energy crisis, which could result in an estimated 6.7 million people living in fuel poverty this winter.

‘Modular build/off-site construction and energy efficiency tend to go hand-in-hand as typically, off-site designs achieve a substantial reduction in carbon as standard. We’re seeing more conversations with public sector partners wanting to develop homes starting with a fabric-first approach to help deliver homes that are more affordable to run for the occupier’.

A groundbreaking ‘pod and panel’ solution

Modularize developed a structural insulated panel (SIP) system for the carbon-neutral Sittingbourne housing scheme. Its team designed a hybrid solution that incorporated volumetric ‘pods’ — such as bathrooms and kitchens — and a panelised system, which involved the off-site assembly of walls complete with windows and doors.

As well as implementing an efficient building envelope and a groundbreaking ‘pod and panel’ solution, Modularize coordinated the mechanical and electrical services (M&E) within these properties to ensure they are fully mortgageable and offer significant energy reduction for end users.

‘By ensuring design for manufacture is achieved quickly, we prevent costly design reworks, supply chain challenges and delays, allowing projects to remain on time and within budget’, commented Matthew Egan, Modularize’s CEO.

This energy-efficient housing scheme featuring self-generating photovoltaic (PV) solar panels and air-source heat pumps demonstrates the potential of modern construction methods to deliver the change we need to see in the housing sector moving forward.

PSP is committed to supporting the development of net-zero buildings for a greener future. Contact to discuss how our end-to-end development management service could assist your next project.