<< Additive Manufacturing, or 3D Printing, is changing the construction industry at an unprecedented rate, and new opportunities are arising as a result. But there are still some obstacles that need to be overcome and even then, it may never fully replace certain traditional construction methods. This article will explore how additive manufacturing could improve this sector and what barriers are preventing it from being implemented. >>

Today, every fifth person in the world lacks access to adequate housing. It affects both the developing and the developed world and the global rise in population during the next decades will make it difficult to meet the ever-accelerating demand.

Construction, historically lacking productivity, is due for a digital overhaul in many areas and recent developments in construction technologies such as additive manufacturing are promising to overcome some of the existing barriers.

The Past, Present and Future for AEC

Historically, the architecture, engineering, and construction sector (in short “AEC”) has been highly fragmented between many stakeholders, and low in productivity compared to other industries. Additionally, the construction industry uses a project-based approach, which means each building presents its own unique challenges and almost all efforts and analyses are bespoke. This is inefficient in terms of resources and has a limited ability to scale.

Nowadays, Building Information Modelling (or “BIM”) has helped to implement digital planning in AEC, but the actual production largely remains done in a traditional, manual fashion - right on the construction site.

In recent years, the sector has witnessed the rise of 3D printing companies around the globe, offering to print building components or entire houses at “the click of a button”, both on-site and off-site in order to meet increasing demand. While some of these promises are certainly pushing the limits of what’s feasible, what is really holding back the adoption of this new technology? We have identified four possible bottlenecks, which we will now proceed to analyse.

1. Technology

In terms of software, a plethora of 3D / CAD and CAM tools already exist, enabling efficient digital design and process simulation. Planners and civil engineers have been using BIM for decades now, whereas CAM was mainly used by manufacturers and fabricators. By connecting these digital workflows, it is possible to bring a digital design to a machine, such as for subtractive processes (milling, drilling) or additive processes (such as 3D printing).

In terms of hardware, current advances and innovation in 3D printing technology tailored to construction are allowing for larger and faster prints. Those systems, usually CNC type (2-axis, 3-axis, or more, such industrial robots) with a controllable mortar pump, are available today, worldwide, and can be installed in a factory or even on a construction site.

In terms of materials, reinforced concrete is the most commonly used material in construction, and it comes as no surprise that we most prominently see the use of 3D printing in construction using mortar or concrete. In this process, the need for formwork is eliminated or reduced, which cuts labor time and waste. At the time of writing, there are challenges around finding appropriate strategies for reinforcement - but the smartest minds in research and development are trying to solve these as we speak.

As Andreas Thoma, Director of Digital Fabrication at Toggle, says:

"In general, AM technology appears to be progressing very well. That being said, most AM products are fabricated layer-by-layer and do not perform well under tension. On the other hand, robotically assembled structures, also a form of AM, are not bound to layers and can withstand high tension loads."

Toggle is an American construction robotics company that developed robotic hardware and software for automating the most physically difficult and repetitive steps in rebar cage assembly. Using large format industrial robots, similar to those used in automotive manufacturing, Toggle is able to dramatically increase productivity in proportion to labor.

2. Costs

Having machines potentially perform most of the work means that the AEC Industry could start automating the production of some or all of the components needed for any given building. This will allow for production around the clock, increased productivity, and help especially where labor is not available or too expensive while increasing safety in the sector.

This also indicates that these buildings, or their additively manufactured components, could be economically more competitive than existing solutions and delivered in less time.

Currently, the material costs are higher than standard construction materials and the staff needs to obtain specific training. Once these costs come down eventually, additive manufacturing in construction will finally be a competitive, if not an outperforming solution.

Regardless of the technologies involved, it is important to understand the implications of cost when being in an early stage of the design process. For this purpose, real-time online configurators can be built in order to have a quick initial way to interactively compare costs for a construction project. You can check out the demonstration below:

Cost Calculator GH model hosted online, Source: Nuri Miller on ShapeDiver.

As Shaun Wu, Computational Design Specialist at Witteveen+Bos says:

"3D Concrete Printing (3DCP) allows us to achieve mass customization and apply material only where it is needed. Thus, the overall cost remains relatively the same as the required volume is less compared to conventionally produced concrete structures."

Witteveen+Bos is a multinational engineering and consultancy firm that focuses in resolving today's most complex challenges around topics such as water, infrastructure, environment and construction.

3. Regulation

This might be the biggest obstacle of them all. Novel technologies have the difficult challenge to adhere to existing standards, such as fire safety, structural capacity, and earthquake resilience. This makes it especially difficult for unreinforced concrete structures to be approved as they need to get tested on a 1:1 scale first.

As Victoria Chavez, Design-to-Print Engineer at technology company CyBe Construction, says:

"It is ideal to generate comparisons and benchmark existing policies; although it is important to start setting new standards that allow us to explore the technology capabilities further."

Since 2013, CyBe Construction has developed hardware, software, building materials, and a digital learning platform, becoming a one-stop-shop for construction innovation such as concrete 3D Concrete Printing and Parametric design as well as a leader in the industry.

4. Interest

The above-mentioned challenges, and opportunities, are not only being tackled by academic and private R&D institutions, but also new and exciting startups and spin-off companies. Some larger construction firms have invested to form their own internal innovation departments to explore these novel technologies and even constructed prototypes - often on their own company campuses. So why has Additive Manufacturing not yet been transferred to “real construction projects”?

This might be due to a low risk tolerance in an industry that has low profit margins. For many construction companies, material and equipment costs required to 3D print homes aren't low enough yet, plus general awareness is still low. Nonetheless, as prices involved with these types of projects inevitably go down, the average consumer will get exposed to the benefits (and in some cases lower costs) of 3D printed homes.

For example, just recently a 3D-printed single family home has been occupied in the Netherlands, raising the level of awareness and interest in 3D-printed homes. Consultancy, design and engineering for this project was provided by Witteveen+Bos.

What's Next?

As we learned in this article, there are challenges for 3D printing in construction on the technological level, related costs, regulations, and a lack of awareness or even interest. However, even though this might still be unknown for some today, the construction industry is undergoing a complete digital transformation as we speak.

It is certain that digital design and fabrication are here to stay and hopefully these technologies can help tackle, among many other things, the shortage of affordable construction in the years to come. In our next series of articles, we will have a look at other challenges that the AEC sector is currently facing.

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<< Special thanks to Alex Walzer for his collaboration during the writing of this article. Alex investigates the role of entrepreneurship for and in AEC when utilizing nascent production technologies. He is a PhD researcher at the Chair of Innovative and Industrial Construction (Prof. Dr. Hall) at ETH Zürich - and can be reached at walzer.tech and @alexnikw on Twitter. >>