Why Kirstie Allsopp was right about detached housing*
*mostly
Riverside Grange in Essex - a typical new build estate
Kirstie Allsopp, co-presenter of property TV shows Location, Location, Location and Love it or List it, sparked a 'feud' with Janet Street Porter with her comments in an interview with the Daily Mail recently. She said that she would "stop the building of detached houses", leading to a storm of criticism by internet commentators on X and elsewhere who called her a hypocrite - and worse.
But honestly, Kirstie was right, with one small asterisk. I will explain why she was right and what that asterisk is in this article.
Contents
What did Kirstie actually say?
The state of new build detached housing
Kirstie's criticisms tested - sustainability
Kirstie's criticisms tested - site use and garden size
Why do people prefer detached housing?
What did Kirstie actually say?
First, the offending passage from the original interview by Cole Moreton:
“Then she comes up with an idea that’s both startling and controversial. ‘I would stop the building of detached houses. They’re not environmentally practical. They don’t make best use of the sites. They have smaller gardens, there’s less community. That gap between the houses is a waste of space.’”
On the face of it, perhaps this does seem to be hypocritical coming from a person who lives part of the time in a Jacobean Mansion, as Kirstie herself says on X. Here is someone living in a type of home that many others dream of, coming out with a proposal to make it harder for others to achieve that dream.
However go beyond that surface-level critique and I think we find a realist rather than a hypocrite, because the criticisms Kirstie made of new detached housing are absolutely true when applied to typical new-build estates being constructed in towns and villages around the country.
The state of new-build detached housing
When I read what Kirstie had said I immediately thought of a housing estate I had seen this summer, on a trip to the small village of North Fambridge, Essex. Called Riverside Grange, it had just finished construction and was being marketed by David Wilson Homes, a subsidiary of Barratt, one of the largest housebuilders in the country. You can find similar estates to Riverside Grange being built in every region of Britain. It has a mix of house types, but the majority are detached houses in various styles.
The Riverside Grange site plan. Credit: David Wilson Homes
Above is part of the site plan for Riverside Grange, showing several detached house styles offered for sale, each with their own name. For this article we'll look in a little more detail at the type David Wilson Homes call the 'Winstone' (number 5 in the plan above), and use it to test Kirstie's main design criticisms: Sustainability, site use and garden size.
First, the key statistics on the Winstone:
2-storeys
4-bed
3.5-bath
160 sq m approx gross internal floor area (as measured from the plans available on the website - shown here),
33 sq m approx double-garage, with 87 sq m driveway/parking area
400 sq m approx plot
130 sq m approx rear garden
Each Winstone is built with a driveway to one side, leading to the garage, which separates it from the neighbouring house. The other side of the house either abuts directly onto the neighbouring driveway, or is separated by a small fenced area less than a metre wide.
Now, to test each of Kirstie's key criticisms. Firstly, that detached houses are not environmentally practical.
Kirstie's criticsms tested - sustainability
There are several factors that affect the energy use of a building, such as how it is heated and how well insulated it is. Just as important is its form, or three dimensional shape. Buildings lose a lot of their heat through their external walls, windows, roofs and floors - the 'external envelope'. The larger the surface area of that external envelope, the quicker heat will be lost.
The Winstone loses heat through four external walls, the roof and the ground floor. But imagine that you took two Winstones and connected them together as semi-detached homes - now one of those four walls is no longer exposed to the outside air, and is no longer losing heat. If you did it again to create a terrace, the hypothetical mid-terrace Winstone would not be losing heat through either of the side walls.
Diagrams comparing the heat-loss surfaces of The Winstone to hypothetical alternative versions
The ratio of heat-loss surface area to floor area is called the form factor. A higher number indicates a less efficient form. As a detached house the Winstone has a form factor of 3. Our semi-D version has a form factor of around 2.7, and the mid-terrace version a form factor of around 2.3. These efficiencies in form would translate into energy savings in heating the house, and our terraced version of the Winstone would use around 12% less energy, in terms of kWh over the course of a year, than the detached version.
All we had to do to achieve those savings was to connect the Winstones together, and leave everything else about the form the same. But there are other forms that would improve the efficiency even more. If we reconfigured the same floor area into the plan of a typical Georgian terrace, this time over 3 storeys instead of 2, then the form factor would be a significantly better 1.8, and the annual energy saving a dramatic 30%. As a flat in a multi-storey apartment block, the improvements would be even greater.
Diagrams showing homes with the same floor area as The Winstone but in alternative typologies.
So on this criticism I think we can say that Kirstie is right, and non-detached houses are much more environmentally practical, as she put it.
Site use and garden size
Kirstie said that detached houses don't make the best use of sites. Whether this is true of any particular detached house is going to very much depend on the site, but in the case of a large estate like Riverside Grange, where the size and layout of the site isn't a major constraint, the housebuilder has the freedom to plan their new streets using a broad range of housing typologies - be that semi-detached houses, terraces or even low-rise flats.
If we return to our hypothetical Winstone terrace, we find that because there is no longer a driveway between houses the plot has become narrower, but can be made longer to compensate and maintain the same amenities. This terraced version of the Winston (terrace ‘A’, in the image below) would have the same number of external parking spaces, the same garden size, and an equivalent outbuilding to the detached version, all on a plot of 345 sq m instead of 400 sq m. That 15% saving in area, multiplied by each plot across the site, adds up to a lot of land that could have been left unbuilt, and kept as the farm it used to be before it was developed.
Diagrams comparing the plot usage of the Winston to hypothetical terraced versions
Alternatively the total plot area could have been kept exactly the same, and the greater efficiency given back in the form of more usable garden space. In this version of the terraced Winston (terrace ‘B’, above) the garden would be 185 sq m instead of 130 sq m - 42% bigger.
So again, Kirstie is right: Non detached forms allow for more efficient site use, which can be realised in the form of bigger gardens or in greater density. Greater density generally leads to savings in infrastructure costs and associated public services, and allows for less of the countryside to be built over.
Is Kirstie a hypocrite?
OK, so she may be right about the problems with a lot of new-build detached housing, but isn't it hypocritical for someone who enjoys life in a detached house to argue against building more?
No, because being against the construction of new detached housing estates is not the same as calling for existing detached housing to be demolished. Existing buildings represent an enormous amount of embodied carbon. Often the best thing that can be done with them is to retain them, refurbish and renovate them to improve their energy efficiency, and live in them - especially if they are well loved, well used buildings. Replacing a street of detached Winstones with a street of hypothetical terraced Winstones would represent a huge waste of resources, but if faced with the choice of how to lay out a new street, it is the terraced version that would be more resource-efficient.
Why do people prefer detached housing?
Generally, three points get brought up in favour of detached houses when the merits of different typologies are discussed: Privacy (specifically noise), space and independence.
If you picked out an existing detached house at random and compared it to a similarly chosen terrace or semi-d, then you'd probably find the detached house does win on all three of those measures. But that relates to housing stock that has already been built over the course of centuries, rather than a) what is actually being built today by volume housebuilders, b) what can be done to improve existing houses, and c) what should be built in the future, which is what Kirstie is talking about.
Old terraces and semi-detached houses, built with solid brick party walls, do transfer noise between neighbours. But new homes built to the modern acoustic standards of today's building regulations provide much better insulation and isolation between dwellings, and existing walls and floors can be renovated to improve their acoustic properties. Detached houses are often bigger than terraces and semi-ds, but this is completely down to design decisions made by the housebuilder - floor area is more or less independent of typology.
By definition, detached houses are more independent than other typologies. They literally stand alone. But what freedom do you get with a Winstone that you wouldn't get with a semi-detached? You would still need party wall consent from your neighbour for work to the wall on the site boundary. You could perhaps build a side extension over your driveway, but you could do that in the semi-d too. I would say the Winstone, and other houses like it, offer the appearance of independence without any of the real benefits you might assume come with it.
So out of the three main reasons for preferring detached houses, two are not intrinsic to the form and the third gains you very little, unless you are on a wide plot quite different from those being offered on new-build estates around the country.
There is a fourth reason people often prefer detached houses - as highlighted by one of the commentors on the Daily Mail story: Status.
“A two up, two down with the toilet in the back yard. The dream from there was always to live in a detached house up on the hill. Now, some have achieved this and she comes out with this nonsense. She is so out of touch or has never been in touch.”
A detached house can be a status symbol, in the same way that a fashion brand can be. Yet, similar to how adding brand label doesn't change the underlying quality of a t-shirt, the 'detached' label doesn't automatically guarantee superior quality in housing - and in fact comes with significant drawbacks for owners and for society when compared to the alternatives.
Should detached houses be banned?
So far I've agreed with Kirstie on every point, so why the asterisk in the title? Kirstie said she would stop building more detached houses. However the UK is a country with a free market in privately constructed homes, and house-builders respond to demand. Many people, for the reasons listed above, are willing to pay more for a detached house, so estates like Riverside Grange get built with a majority of detached houses because that is what will maximise the profits for the developers.
But developers also respond to planning policy and building regulations.
Rather than be prescriptive about typology, an alternative approach would be to look at the outcomes that Kirstie cares about - energy use, garden space, land use - which nearly everyone would agree are important, and set high standards that promote better typologies where appropriate.
Setting home energy standards that are related to energy use per square metre of floor space (also known as Energy Use Intensity, or EUI) would allow the benefits from efficient building form to be taken into account in a way that the current building regulations don't. Housebuilders will adjust their designs to comply, which could be by building semi-d's or terraces, or it could mean finding an innovative alternative solution. Either way the desired outcomes would be achieved.
There will always be a place for the detached house. There are always going to be sites where a single house is the most appropriate response to the context and the needs of the client.
Conclusion: For a better nation, embrace renovation!
We live in a country filled with terraces and semi-d's that people feel are too small and noisy, and detached houses that waste far more energy than they should. What should we do about it? Renovate them! Existing houses can be insulated to improve both acoustic transmission and heat loss, and they can be extended outward, upward and even downward to add internal space, all in a way that makes them more stylish. Just look to the annual Don't Move Improve awards to see what can be done with any housing type, from flats all the way up to grand detached homes.
In the quest for better homes, the solution often lies in the renovation of our existing housing stock - but then as the face of Preview Studio, I would say that, wouldn't I! Preview Studio offers a feasibility renovation and extension design service that allows you to see your home's potential - including rapid turnaround visualisations and advice on how to improve energy efficiency.
Ready to see what your home could become? Give us a call or email us with your questions, or simply get started today.