Why prefabs have never really taken off — and why they will inevitably do so, now.

Many developed economies are facing a house crisis that is not just about the cost of land in major cities, but the increasing cost of construction. In the UK, Labour has proposed building new towns, but unless a solution to these construction cost increases is found, it won’t solve the problem. Modern prefabs have often been proposed as a solution, but the fact that there aren’t beautifully designed, affordable prefab houses everywhere was never about the architecture, but the business dynamics, the infrastructure and the foundations.

In the UK, labour is proposing a new generation of New Towns so solve the housing crisis

The business dynamics were that regulatory requirements for insulation, flood protection, environment protection etc. put the build cost of a three bed house in the UK (it’s cheaper in US) up from around 100–150k GBP (an attractive looking uninsulated building in a mediterranean climate still costs this) to 400k, meaning that ‘affordable housing’ with land is unaffordable at 600k. This is causing a housing crisis everywhere with regulatory creep (you don’t actually need much insulation if you have non emissions energy, and fragile and toxic exterior insulation is going to be a huge problem for building maintenance in the future).

Structures need solid materials, insulation needs trapped gasses and today, these are often air trapped in external foam cladding. However, the render on the outside that makes it look like a solid material is often a few millimeters thick and will chip off over time. In addition some of the chemicals being used in the foams may end up being hazardous. These building methods, which are one of the few ways of achieving modern insulation requirements, are not going to stand the test of time.

These high costs meant that in order to deliver anything affordable there needed to be consolidation in the construction of regular ‘wet trade’ (i.e. built on site) domestic building. Large developers would put in infrastructure and build cheaply (modern, pitched roof domestic houses have unusable attics due to low cost stapled trusses at very regular intervals). This consolidation prevented new build alternatives from entering the market and competing, they didn’t have the scale.

Cheap, modern domestic architecture has trusses, so regularly spaced that it means attic space is unusable.

Non domestic buildings from light industrial to out of town retail and office spaces have been assembled from pre-fabricated, factory-made components, for decades, because the market dynamics were different. Domestic prefabs have meanwhile adorned the covers of magazines, designed by small architect firms with price on application, but nobody has reached the scales needed to make them viable, Even when people like IKEA have tried, they haven’t really gotten anywhere, and the few success stories such as Huf House are premium products, not suitable for low cost housing.

Prefabs adorn the covers of architecture magazines but have never become ubiquitous. They tend to be one-offs rather than part of a new vernacular.

But the regulatory floor is rising, lowering margins to breaking point for existing models of domestic construction and the only thing that can lower that regulatory floor again is innovation. Taking a trivial example, wireless lighting means we no longer have to chase switch cabling into the wall. With newer, flood protection requirements, innovations such as screw piles (allowing two people to lay flood proof foundations on soil or clay), could be a game changer.

Screw pile foundations could be a game changer.

So it is inevitable that prefab construction for domestic architecture is coming. It is the only way we will be able to build the affordable new towns that Labour are proposing for the UK, for example while keeping them compliant with newer building regulations.

A vernacular architecture is a repeated style where you may not know the individual architect and individual houses are variants on a standard theme. Here are Edwardian houses in London. Prefabs could potentially create a new vernacular style rather than the last decades which have been about low cost pastiche or one off architect design buildings on TV’s Grand Designs. Where the attempt by the grand designs host to create a prefab style, failed as it didn’t have the scale.

But to make it happen will require starting at scale — with, say, a modular design for a new town all based on screw pile foundations, radically lower infrastructure costs via ,say off-grid technology, timber frames and factory build, mix and match modules shipped intact within containers (not containers themselves — they are dumb idea for domestic construction) and with kitchens and bathrooms already installed.

Eichler is on of the few people to have developed a modern vernacular.

We don’t need innovative, architect designed, bespoke buildings with unique floor plans, we need modular, mass produced components that mix and match, for variation. We need a new prefab vernacular.