The Hub’s Platform Design Lead, Jaimie Johnston, looks at the scale of the UK’s need for more and better housing. Meeting this challenge will require a range of solutions, and this blog sets out how the Hub’s Platform programme will make a vital contribution.
Last September, housing secretary Robert Jenrick stated emphatically that Modern Methods of Construction (MMC) will form a central part in delivering the UK’s housing needs, providing ‘not just more homes, but more beautiful, more sustainable, better quality homes in all parts of the country.’
We all know that the task facing the residential sector is huge. Within the Construction Innovation Hub’s Platform Design Programme, our work to ‘Define the Need’ has been looking at the nature and size of the task for construction across a range of sectors, including residential. But ‘residential’ is not a unified category. A tower block and a two-storey house are fundamentally different building types, requiring different construction approaches.
Through a systematic understanding of the residential landscape, we hope to provide the information that will allow us to move forwards with solutions that deliver better outcomes for housing, the economy, society and the environment.
The nature of the task
The residential landscape is made up of a complex blend of typologies; ranging from a single house to a large residential development of hundreds or thousands of apartments. To understand the requirements of the residential sector, we have found it helpful to categorise these systematically. The diagram below creates the ‘Periodic Table’ of housing; it identifies factors which require distinct differences in technical performance, including fire, acoustics, and access to natural daylighting.
Housing typology ‘periodic table’
Moving out from the centre the first key differentiator is the presence of a core:
- if there is no core, then the asset is a type of house;
- if there is one core, this is a tower
- if there are multiple cores, this building is a multi-occupancy typology.
This makes a crucial difference in all sorts of ways. As just one example, the fire and acoustic separation required by the floor in an apartment building separating different households is more onerous than in a house.
Next, we consider the presence of party walls. For instance, a house with no party walls is detached, while a house with party walls is semi-detached or terraced.
The next factors are
- Number of storeys (which trigger differences in fire strategy at a certain height)
- Number of aspects (needed for larger apartment types), and
- Location of circulation (deck access vs. central corridor, leading to double- or primarily single-aspect apartments).
The developer Urban Splash started on one portion of the ‘periodic table’ with their Row House and Town House. The volumetric modular Row House could be categorised as:
- Core: none
- Party walls: yes
- Storeys: 3
- Aspect: dual
- Circulation: internal
This narrow focus allowed Urban Splash to create a beautifully designed and award-winning product that was refined and perfected before they expanded their range. Their new ‘Mansion House’ can be categorised as:
- Core: 1
- Party walls: yes
- Storeys: 6 (mid-rise)
- Aspect: dual
- Circulation: internal
This systematic definition of the variables that define the residential asset, means that we can better understand the needs within the sector and identify which solutions or systems are best suited to which sets of needs.
The size of the task
Having established a framework for categorising the residential market, we now need to establish the proportions of each typology.
The UK Government publishes statistics on the number, tenure and region of residential dwellings started and completed pre quarter. These provide an excellent resource for understanding the potential scale of the market. The figures for the 169,500 completions in the year 2018 – 2019 are below:
Breakdown of 169,500 completions in 2018 – 2019
The majority (65%, or 138,720) were delivered by the private sector, with the remainder delivered by Housing Associations (HA’s) and Local Authorities (LA’s) – 30,780 in total.
However, the size of the ‘residential’ sector doesn’t stop there. Our ‘Define the Need’ project is identifying the commonality between the pipelines for the Department for Education, the Department for Health and Social Care, the Ministry of Defence, and the Ministry of Justice. We have discovered just how much residential need these sectors have, in addition to what we traditionally consider ‘housing’. The latter two departments already build large volumes of residential accommodation, for example: a huge pipeline of single living and family accommodation for military personnel (approximately £2.4 billion). So, the task for residential design and construction is even greater than we might think.
The size of the opportunity continues to grow. If we consider that the typologies within residential also apply to other sectors, we see that we can gain efficiencies across sectors. For instance, many public sector space types have a ceiling height of 2.5m – 2.7m which is typical in residential. More importantly, a typical classroom has a depth of 7.8m, which is directly comparable to the depth of a standard apartment. Teaching blocks and healthcare wards have two such ~8m spans separated by a central corridor, which is also analogous to a double hung apartment type with a central corridor.
Residential isn’t only a huge sector in and of itself. The size of the opportunity is even greater when we add in the needs of other sectors and the potential for solutions to work across sectors.
Considering the nature and size of the task, it’s safe to say that no one solution can be the silver bullet. The numbers and variety of homes needed is such that no single construction system can deliver the entire pipeline. We will need a mix of systems including platforms, volumetric modular, cross laminated timber and panelised, to cater for different typologies.
Adopting different approaches will also ensure the richness of architectural variation that supports placemaking and regional context.
At the Hub, the Periodic table has helped us identify where our Platform Solution has the strongest role to play; in the mid-rise multi-occupancy typology. Using the Periodic table, we see that the following characteristics are most relevant to Platforms:
- Cores: multiple
- Party walls: yes
- Storeys: 4-14 (mid-rise)
- Aspect: single
- Circulation: internal.
The size of opportunity for Platforms
The Hub’s thinking only considers those schemes delivered by HA’s and LA’s which, the Government stats show, is 30,780 dwellings.
Using the Periodic table categorisation, we can recognise that houses may be more suited to a modular approach opposed to the Platform Solution.
With this in mind, we will therefore focus the Platform Solution purely on flats. Within the 30,780 delivered by HA’s and LA’s, 35% were flats; around 11,000 apartments per year. Using the percentage breakdown of 1- , 2- and 3-bedroom apartments within this mix, and the nationally described space standards for these, we can calculate an average area per apartment of around 60m². So, this would represent 660,000 m² of housing, and at a build rate of £200/ft² (currently a difficult target for apartments in many markets; but which a Platform approach can make possible) this is an annual pipeline of £1.42 billion.
Clearly, not all of this could be delivered by Platforms (for instance, deck access typologies and high-rise towers) and there would be other factors that would limit the size of the market. However, it proves that even small sections of the residential landscape represent huge pipelines.
With this in mind, we must look broadly at the best solutions to service these pipelines.
The benefits of the Platform approach to Flats
We can articulate the benefits by considering the housing secretary’s quote in more detail.
‘Better quality homes’
The Hub programme is structured across four themes – Value, Manufacturing, Assurance and Digital. The Manufacturing theme specifically seeks to offer significant benefits in terms of quality, cost, delivery time and whole life value, while the Assurance theme is predicated on ensuring safe and resilient buildings that are built to deliver long-term societal outcomes.
There is a mutual benefit to both the residential and wider public sector in adopting the sub-assemblies that are developed within this framework. The residential market would gain access to the highly manufactured components and all the benefits they bring in terms of quality, certainty and cost.
For wider government, the residential market would increase the addressable market for Platform components, boosting the overall pipeline to accelerate adoption and accentuate economies of scale.
Initially, this might apply to the ‘unseen’ elements, such as structure, services distribution, etc. However, as the work of the Hub harmonises standards and specifications across sectors, there is likely to be a greater overlap and further benefit. For instance, as all public sector assets head towards net zero carbon, elements such as the ‘performance’ component of the facade will become increasingly standardised across all sectors.
A key aspect of the Hub’s manufacturing theme is ensuring optimisation of materials and creating components that facilitate efficient production. A component that is going to be used thousands, or hundreds of thousands of times justifies a huge amount of effort in refining its design and performance.
But the Hub is looking to embody outcomes that go beyond this. The ‘Value’ theme considers ‘wider social, economic and environmental factors’, and ‘considers them across the full investment lifecycle.’
This means ‘sustainable’ in the broadest possible sense, for the greatest possible benefit (and as the housing secretary says, ‘in all parts of the country’.)
The final theme of the Hub is Digital, which considers how to use the power of digital workflows to improve every aspect of the project lifecycle.
The PRiSM to Platforms workflow already demonstrates how leveraging standardised Platform components in an automated design process facilitates higher quality, more individualistic design. This creates an evidence base through simulation, to optimise energy balance, overlooking, pedestrian movements, integration with local context, etc. We can then compare all of this against the ‘Value profile’ for the project or programme to test more rigorously that the design is meeting the needs of stakeholders and society.
In construction as in every other aspect of our lives, ‘manufactured’ needs to become synonymous with beautiful and elegant, yet practical and functional.
A complex sector, multiple solutions
This thinking makes it clear that the solutions for the residential sector need to be numerous. For example, even if the major modular manufacturers were working at full capacity across a mix of houses and apartments in the private and HA/LA sectors, there would still be a huge need to be addressed.
Some of this demand can be delivered using components that are being developed anyway for education, healthcare and other public sector residential typologies. Another positive step.
The Platform programme offers a fantastic opportunity to the residential sector; to leverage high quality manufactured components, to strengthen and support regional Platform supply chains and to support the delivery of the housing secretary’s vision.
Above all, there is a huge opportunity to avoid players getting in each other’s way by chasing after the same parts of this large and complex market. Instead, we should match residential typologies with the optimal delivery solutions, to create benefit for all and get on with tackling the UK’s housing need.
Jaimie Johnston is the Hub’s Platform Design Lead and Director & Head of Global Systems at Bryden Wood.
He was the author of the strategy documents ‘Delivery Platforms for Government Assets: Creating a Marketplace for Manufactured Spaces’, ‘Platforms: Bridging the gap between construction + manufacturing’ and ‘Data Driven Infrastructure: From digital tools to manufactured components.’ These were adopted as a key articulation of the government’s aspiration to adopt a more manufacturing-led approach to construction, reflected in the Infrastructure and Project Authority’s – proposed adoption of a Platform approach to Design for Manufacture and Assembly.