Unlike prefab houses, where all the components are constructed in a factory beforehand, the D-Process simply takes the CNC machine onto the building site along with the required sheets of wood and makes the components there.
Also unlike the traditional prefab house, which has a reputation for being cheap looking and flimsy, these houses are high performance, sustainable and bespoke designs that may well serve as a model for the future construction of houses.
The whole process from manufacturing to completion can take as little as six weeks. Humans Invent spoke to the managing director of Facit Homes, Bruce Bell, to find out more.
What is CNC?
CNC stands for computer numerical control. CNC is a very generic term that covers a huge amount of different processes and manufacturing techniques. We use CNC routing. Within routing, there are a couple of different CNCs as well. We use a 3-axis CNC router.
Our machine looks like a big printer. You get a big flat sheet and we can cut shapes out of it and also cut down to different depths as well which allows us to do engraving or cut numbers or rabbet…that kind of thing.
Our machine looks like a big printer. You get a big flat sheet and we can cut shapes out of it and also cut down to different depths as well
Is it a new concept for customers to send in a CAD file?
The CNC process has been around for about twenty years but the actual programming side of it has become a lot simpler. The CAD formats that you can programme into a CNC machine are much more prevalent and therefore it is much more accessible for a wider audience. And because the programming is more flexible it allows people to create a lot more variation in files without any additional costs.
The big change in CNC manufacturing as opposed to traditional manufacturing is its lack of set up costs so you can feed through a thousand different drawings and they all cost the same whereas in the past manufacturing has always been based on tooling or setting up which drives people to produce the same thing over and over again. This new generation of digital CNC manufacturing allows a lot more flexibility and for everyone to be different.
Tell me about the digitally manufactured houses?
I knew the tooling was out there and started having small scale things produced and realized it was very cost effective. Understanding this technology was out there which allowed you produce thousands of different components cheaply I thought, surely you can produce a whole house this way? That was the task we set ourselves, to build one house with one of these machines and do as much as you possibly can on that machine alone.
Has this been successful, have you completed any houses?
Yes, we’ve done quite a few. We’ve done a house in Hertfordshire, we’ve done a micro hotel pod in Somerset, we’ve done houses in Denmark, we’ve done a small infil house in West London. The houses are all very high performance so we are producing very sustainable, ecological housing.
Talk me through the process.
We made the first few houses from our workshop with our machines but we always realised there was potential to take the machine to the building site, which removes the need for a factory and thus reduces overheads. Basically, we have a shipping container with all of our manufacturing kit inside it. That gets dropped onto the building site and then the materials get delivered directly to the building site, then we machine, manufacture and assemble it all there and then.
The 6 weeks to make and build this house includes the manufacturing aspect.
How many people do you need to work on a house?
It is very simple, you have one machine with two people machining the components and stacking them up. It takes a little longer to machine than assemble the lego-like blocks into the house. So as well as the two people onsite with the machine, making a big pile of blocks, once a week for one day, a team of four guys come in and put it together. It is very simple, it’s actually very lo-tech in its assembly but very hi-tech in its production.
How long does it take to make one of these houses?
Last year we did a large detached house and from dropping the machine on the building site, doing all the fabrications for the ground floor, the walls, the roof and all of that stuff, it took six weeks including the production of it. Although you quite often see buildings go up in days, you haven’t seen how long it takes to manufacture. The 6 weeks to make and build this house includes the manufacturing aspect. We build very high performance and very bespoke – that is the key thing, every one we do is completely different from the last.
Is there a lot of input from the owner?
In one way it is a very traditional architectural process: we have a private client who comes to us and we design it for them, we sketch, we think about what they want and do all the traditional stuff. Once the design’s agreed then we start to feed it into the digital processes. We create a very detailed, 3D computer model which contains everything in the house and they get to walk through it virtually and they sign it away. Once they have signed it, we just go on and produce it and it rolls very quickly from there.
What materials do you use?
The whole building chassis is engineered timber, so that includes the ground floor and the walls, the roof. Internally it still looks fairly traditional, with plaster board linings etc. Quite often the actual bit we fabricate, although it looks amazing when it is going up and very digitally fancy, gets finished in a traditional way. Sometimes, when running a traditional architectural project with a builder, it can be very hard to get them to do the tricky details, to do the difficult stuff whereas we naturally do that anyway because we are the designers.
Are your houses the built to last?
Yes definitely. People often ask my ‘how long does timber last for?’ but actually some of the oldest buildings in the world are made from timber and if you look at a brick building, it is just brick walls with a timber roof and if you let that roof leak and you don’t look after that building it will decay and fall to the ground at some point. But any building, if you maintain it properly, will last forever.
