‘Prefab’ is a broad term in modern home building that manages to describe nothing specific while covering almost everything.
There are a number of different approaches that can fit under the ‘prefab’ banner, which is why it can be a little confusing.
So, we thought we’d break it down and look at what some of the terminology means, what the appeal is, what the limitations are, and also where we sit within this area.
What is a prefab home?
Prefabricated houses, often referred to as prefab homes, are so called because they are primarily manufactured in advance off site, then delivered and assembled on site.
Historically, prefabs have been much maligned in the UK, having been predominantly associated with low quality, high volume housing that replaced stock destroyed by bombs in the Second World War. But such prefabs were only intended to be temporary, which reflects the standard they were built to, even though some remain standing to this day.
Whilst there is still some stigma around the term, modern prefab homes are now more often associated with quality and efficiency.
‘Prefabrication’ can be roughly defined as ‘made before’. Traditional house building methods have long had elements of prefab to them, with components like timber roof trusses being made off site. However, by using ‘prefab’ to allude to a more modern method of construction, many companies now describe the virtues of their different approaches with this blanket term.
The lack of clarity around ‘prefab’ and the assumption by many that it only refers to a modern, cost effective method is why it is used so widely, but any home can be considered prefab if some part of it is made before arriving at the site.
Three other terms might sound familiar - these are often seen as interchangeable with ‘prefab’. We consider these subcategories of the prefabricated home with their own specific traits: modular, volumetric and kit homes.
What is a modular home?
A modular home is a type of prefab home built in large sections, such as wall and roof panels; a bit like a big Lego set. Most of us will have seen a picture like below, where an entire wall (often with windows already installed) is craned into place on site.
Baufritz, a leading German prefab company, is a modular builder that prefabricates entire wall sections in a factory and cranes them in to place on site. This often gives the appearance of a home that will only take days to assemble. However, once the building envelope is in place there is still months of work ahead for the fit out to be completed and, of course, as with all prefab homes, the foundations will need to have been completed already.
For more examples of modular homes, check out this Grand Designs article.
'Modular is not delivering, here's why' is an article on the state of construction and modular building that states "Construction has been struggling for years with productivity flatlining at a low level, poor build quality, high cost and uncontrollable time schedules.
Ideas of volumetric modular construction, proprietary kits of standardised parts, and buildings prefabricated off-site, have returned in various guises over the past hundred years yet not been able to change how we build, let alone revolutionised construction. One wonders why." Read on.
What is a volumetric home?
Volumetric is defined as ‘the measurement of volume’ and, in this case, is used to describe the volume of air in a room or section of a home.
Volumetric modular manufacturing involves the prefabrication of a number of larger, fully finished elements. Considered a type of modular home, the volumetric modular units are joined together on site to form complete buildings. These ‘modules’ can be pre-fitted in the factory with electrics, plumbing, heating, doors, window and internal finishes.
An approach that is typically used for larger developments, it has the highest degree of standardisation and allows for an extremely quick assembly time on site as so much is done in the factory.
An example of a volumetric house building company is nHouse, which offers various sizes and configurations of a standardised home product.
In our opinion, volumetric homes are less successful for individual customers. One-off volumetric homes still have the factory and production line and rely on standardisation and, added to this, it is not always that easy to find a site that will perfectly suit this type of standardised house.
What is a kit home?
Self build ‘kit homes’ are prefabricated homes delivered to a site flat-packed for assembly by someone else, e.g. a contractor. This self build option has the most potential for individual involvement and often means that you are responsible for the construction of your own home.
As the name implies, the components of the home are created as a prefabricated kit to be put together on site. It might require professionals but often can be built or at least managed by the owner, saving costs. It is aimed at those who wish to be very ‘hands on’ with their project. The amount of kit that you purchase may vary, from just the building envelope alone through to a complete home package.
An example of a kit house company is HebHomes.
Why are people interested in prefab?
As a result of the industry using these terms (prefab, modular, kit and volumetric) interchangeably, we have seen confusion rise over the years. Throw ‘flat-pack’ into the equation too and it’s no wonder that people find it hard to understand who does what. Some companies happily use a number of the terms to describe their offering, and whilst each has its own pros and cons, they do all sit under the broader church of ‘prefab’ in that they involve advanced, off site production of some sort.
Despite the slightly blurred lines, there are a fast-growing number of people in the UK considering the prefab approach to building their own home. Although it is not a new concept, advanced and innovative prefabrication techniques now offer huge benefits. The low quality, post-war prefab homes are a thing of the past and have been superseded by high quality, 21st century buildings.
Many customers want the certainty that a modern prefab home can give them, reducing a lot of the risks inherent with a more traditional construction route. This will range from certainty over costs (with many companies offering fixed prices) and timelines, through to a guarantee of quality and a higher level of environmental performance.
Add in a faster overall programme and it is easy to see why this solution is reducing the stress levels of aspiring self builders.
What are the issues with prefabrication?
The conventional idea of prefabricated homes is mostly modular or volumetric and is often referred to as the future of house building due to the efficiency of mass, factory based production. However, there are some limitations that aren’t so widely discussed when it comes to individual homes.
Calling something prefab does not necessarily mean it is well made - many factories still rely on the manual skills of individuals on a production line.
Factories like to produce fairly standardised products - this can limit the overall design options available to a customer.
Delivering large components to sites can present logistical challenges - not all sites can have a crane get close enough.
There is a lead time - although work on site might be shorter, there is the production time in the factory beforehand to consider too.
Higher cost - factories have overheads and need a constant output to remain efficient, which can result in charging the customer more.
For us, ‘prefab’ is in many ways an outdated conversation. Factory based home production will continue to have constraints and because of this we believe that digitising the process is the next step, and is where the home building industry should be turning its focus.
The benefits of prefabrication without the constraints?
Facit Homes has featured in many articles that talk about prefab homes, such as a roundup of ‘5 prefab housing innovations that raise the bar’ in The Spaces.
Whilst we subscribe to much of the ethos around prefabricated homes, we don’t fit very neatly into any category because - by looking at the companies people generally associate with ‘prefab’ - we aren’t doing the same things.
For example, whilst we manufacture many parts of the home off site, such as our advanced structural system (the Facit Chassis) we don’t prefabricate finished wall sections or complete rooms at scale in a factory setting.
We’re also not a kit home company that leaves the customer with the stress of completing the build themselves.
Instead, we are focused on leveraging digital manufacturing technology to ensure the highest quality and performance levels for our homes, whilst giving ourselves the flexibility to be able to individually design each one from scratch. No two sites or customers are the same and in response we’ve developed an approach that brings us the best of both worlds.
Our method is perhaps more aligned with modern car manufacture, with all the parts being digitally designed and produced, before being delivered to site for assembly 'just in time'. It keeps things efficient, removes the need for a huge factory and makes the most of all the amazing specialist production facilities out there.
We also handle the whole process from design to manufacturing to construction, offering our customers a complete turnkey service. This includes dealing with all the tricky bits at the start like groundworks and utilities; the parts that need experience and expertise in order to be done correctly.
Regardless of exactly how we fit in, we optimise the prefabrication elements of our builds in order to create high performance, bespoke homes - and if they are best described as a ‘prefab' then we are happy to be on board.
Find out more about our approach by exploring The Facit Home.
