The construction of buildings will be cheaper and more efficient. This is how it will happen.
What is the problem today?
If you’re not convinced of how outdated the construction of buildings is, consider this thought experiment.
Imagine a factory producing cars and a building construction site. The factories producing automobiles are almost fully automated. The amount of people it takes to build a car is very small compared to its complexity. Every last detail will be executed according to the blueprint of its manufacturer. Parts are flown in from the other parts of the world, where it’s more convenient or cheaper to make them. Cars are built according to a very high standard. The tolerance for mistakes is very small. Everything must be built according to a very strict quality control. And the price of a car is relatively cheap in hindsight of its complexity. While an average car has about 30 000 components and costs 31 400 USD, an average family house has 3 000 components , yet costs 283 057 USD .
Now let’s look at the building construction industry. It takes not only a lot of materials but also an immense amount of manpower to erect a building. There are a very few components which are prefabricated in factories (e.g. windows, doors, HVAC), most of the work is done on site. The quality of this work varies a lot according to location, building crew etc. however it is certainly true that the preciseness of the finished elements is very low compared to what is to be found in other industries. For example while error tolerances in the carmaking industry are measured in mm, in the construction industry it’s rather cm or sometimes even tens of centimeters.
Erecting buildings is also very expensive. The shortage of housing in many countries is a direct result of construction being too difficult and expensive. The most glaring difference between the two industries is the lack of change in construction. A car factory looks nothing like one 50 years ago. A construction site? I bet you it’d be hard to identify a photo taken there 50 years ago and today. The big question is how can the construction industry be improved in order to reduce costs and increase preciseness?
A new design method
Up until about 30 years ago the design process of the building looked like the following: The architects drafted the plans of the to be erected building on paper. This was revised and made more and more detailed many times until it was decided to be ready for construction. The architects and the engineers responsible for structure, machinery, HVAC etc. were basically encoding their three dimensional visions into plans. These plans of the building were handed over to the construction company which made it into a real three dimensional objects. So the workflow looked like this Vision (3d)->Plans (2d)->Building (3d).
Nowadays computer technology has improved and most architecture firms are transitioning into designing in Building information modelling (BIM). BIM is a whole new field of science, it means basically that every aspect of the house is modelled on the computer in a three dimensional model. This model is accompanied by a huge database, which has all the important metadata regarding these elements (type of material, finishes, price etc.) Ideally the BIM model contains not only the architectural elements but also machines, HVAC and load bearing elements. There are many levels of detail this can achieve (link about LOD stages) but all in all if done properly a virtual model can be created which is very close to the reality up until very small details. Now, this is all very high-tech and is maintained throughout the design process. There is unfortunately a big “but”. It’s not this actual model which is used to build the actual building.
It goes usually like this: the BIM model is converted back to 2d, into traditional drawings. Yes, the construction companies still work with big sheets of paper hanging on the walls of the building site.
So now the workflow of creating a building looks like this Vision(3d)->BIM(3d)->Plans(2d)->Building(3d). It’s easy to see that the biggest loss of information happens when the conversion of 3d to 2d happens. By losing one set of dimensions, no matter the amount of drawings produced, information gets lost. It’s easy to see how the efficiency of the construction industry could be improved vastly. Of course handling BIM models on site is not very easy to implement.
Fortunately advances in the technological industry could come to our help. Of all the recent technological advancements Augmented Reality (AR) has the biggest potential By propagating AR into the construction working force, the need for 2d paper plans disappears. The workers can instantly overlay the contents of the model onto reality which makes it not only easier but also preciser to assemble the different construction elements. The designers and engineers are freed up from the work of creating traditional drawings and can use the saved time to create more efficient and better working buildings. The construction companies will also benefit from this. No more issues of having to work from outdated planes, because those are the ones printed out (happens more ofthen than you might think…), more efficient working conditions. AR makes it even possible to learn the traits of construction on site (think of it like the first tutorial levels in a computer game)
A new construction method
It’s evident that the actual construction has to be renewed in order to revolutionise it. Many experts think that the holy grail of doing that is prefabrication. (here)(here)(here). I will explain why it is NOT the only solution and what else can be done.
Prefabricated construction means that the building components are produced somewhere offsite in a factory and transported to the construction site. There they are assembled into a house. Because some aspects of building a house are repetitive they can be produced in a factory more efficiently. Higher quality precision is also guaranteed because of the factory controlled environment. Construction time is greatly reduced since the parts can be assembled quickly on site. Research shows that on smaller scale projects the average cost of construction can be reduced by up to 50%.
So why prefabrication then not the complete solution? Why can the construction industry be revolutionised the same way as the carmaking industry was?
The two breakthroughs which made cars easier than ever to produce is the conveyor belt and the robotic industry. It is the fact that cars are quite uniform which made it possible to use automated construction process. An average car company produces a dozen of different types of cars. There are many more options to configure them differently but that doesn’t affect their structure or body. The underlying platforms are even shared by different types of cars. For example 13 different types of cars use the same PQ35 platform in the Volkswagen group.
The building industry doesn’t work like that. Every building is very different.
Because of its location, it has to face vastly different climatic conditions. Its scale can vary from a small pavilion to the size of a huge factory. Different types of soil ask for different types of foundations and structures. There are different building codes in every country and every city. This all makes to impossible to create just an assembly line which creates a very similar output every time. The design of buildings also varies a lot. Architects spend a lot of work designing unique buildings which suit their locations. If all buildings were the same we would quickly end up in an uniform city out of a dystopian movie.
So prefabrication has its limits. But what other alternatives are there?
I think machine fabrication is our best bet. It involves two types of machines: building sized 3d printers and smaller fabricators. The 3d printers create the shell of the building. This is used as the primary structure and insulation against the outside temperatures as well. Once the outside shell is complete the smaller fabricators assemble the doors, windows, machinery and various fit-outs. These work the same way as the fabricator machinery in car factories. The only difference is that they can move inside the building.
This method combines the advantages of prefabrication without its lack of adaptation. It saves labour, then it operates almost autonomously. Raw material cost can be reduced, since the amount of material needed can be calculated and executed more precisely. It can be reprogrammed easily to create different building types, in different location where the conditions vary. The challenge of using a 3d printed construction method is to upscale the current printers so they can be used for construction. It also vital that thefabricators have a high level of artificial intelligence. This allows them to use their tools to do various works that have to be done while the construction takes place.
How far is this from today? Regarding upscaling 3d printing there have been some experiments in this area: The aim of this house is to be entirely constructed with a 3d printer. In the swiss university ETH there is an entire department dedicated to research the digital fabrication in construction. This is an experiment by them:
Results
It is no doubt that the construction industry has to be renewed. This will allow building to be cheaper and more accesible to people in need. The amount of money needed for shelter is reduced in a way that households which can’t afford cost of shelter will be able to do so. No matter if it’s prefabrication or on- site fabrication the aim is to create a more accessible construction industry.
