There is a huge demand for insulation for residential buildings in Germany. A project at the TUHH is developing simple and sustainable methods—using modern 3D printing.

Especially now in the cold season, people want their homes to be cozy and warm. The better the exterior walls are insulated, the better this works: the cold stays out, the heat stays in, and with good insulation, heating costs don't skyrocket.
And this is not just a question of personal comfort. The German Building Energy Act specifies minimum standards for the insulation of houses – both new and old. For example, EU directives stipulate that when an old building changes hands, the new owners must meet certain insulation standards within two years, for which subsidies can also be applied for. The need for insulation is huge. But progress in meeting this need is slow in Germany. First and foremost, as in other areas, there is a shortage of labor.

Insulation panels to be printed directly on the construction site

A project by the Technical University of Hamburg (TUHH) and the Hamburg-based engineering service provider TECCON Consulting & Engineering is looking for solutions to insulate facades easily, quickly, and sustainably – using modern 3D printing processes. With the support of the Hamburg Investment and Development Bank (IFB Hamburg), the two partners conducted a feasibility study in 2025, the results of which are promising. The application for a three-year follow-up project is currently with IFB Hamburg. The core of the project is to be able to produce modern and sustainable insulation panels directly on site, i.e., at the construction site, using a 3D printer. These panels are designed to be so easy to handle that they can be installed on the facade with significantly less manpower than before.
It all started with a personal project by a TECCON employee: she had bought a house and wanted to renovate the facade to make it more energy efficient. “Back then,” says Oliver Grunewald, architect at TECCON, “we first discussed the question: Can insulation be sustainable? Can it be made truly efficient, ecological, and recyclable? Through the use of new, innovative processes?” This led the engineering service provider to approach the TUHH Institute for Industrialization of Smart Materials (ISM) to address these questions in a feasibility study.

New ways to achieve climate goals

Maximilian Keller, project engineer at ISM and head of the project, comes from southern Germany, where people talk about “Häuslebauern” (house builders). “We would like to get to the point where house builders can insulate their own facades at some point,” he says. But even if that is still an ideal in the distant future, new processes should already save on labor on the construction site. Maximilian Keller gives an example calculation: “Let's say you need ten workers to insulate a house. If, thanks to innovative methods, you now only need two people, the original ten can insulate five houses in the same time instead of just one.” Of course, this is only an illustration, says Keller, but: “We need new ways to achieve climate targets.”
That's why Maximilian Keller and his team are working on designs for insulation elements that are not only easy to attach to the facade, but also so light that people on a construction site can carry and install them on their own. They can't be too big either – precisely because a single person has to be able to maneuver them. But too small would be just as counterproductive. “Then you have too many edges between the panels, and every edge is an invitation for water to penetrate,” explains Keller: “You simply have to find the optimal point in terms of the right size.” These elements, in exactly the right dimensions, are then to be manufactured directly on the construction site using specially ordered equipment in a 3D printing process. Maximilian Keller calls this “insulation through design” – also to emphasize that the TUHH institute develops designs and processes, but not the materials.

Hemp as insulation material

The designs used are based on so-called TPMS structures. These have a small volume but a very large surface area and are therefore lightweight. Their three-dimensional structure is repeated continuously inside. The organic, continuous curves distribute stress evenly, thus avoiding weak points that occur at the connection points in conventional lattice structures. This makes the material highly resilient. And they enclose large amounts of air, which makes them the ideal insulating material. Complex TPMS structures can only be produced using additive manufacturing, i.e., in a 3D printer.
“Some TPMS structures also enclose two spaces,” says Keller. “You could fill one space with an insulating material, such as hemp, and leave the air in the other. Hemp has the dual advantage that its fibers strengthen the structure and it is also completely biodegradable.”
The material Maximilian Keller and his team are currently using to print the first prototypes of their components is recycled PLA, a bioplastic made from corn starch. PLA is compostable, but only in industrial facilities. “Not ideal, but better than petroleum-based plastic,” Keller sums up. For the future, the team plans to use geopolymers instead of PLA, a kind of environmentally friendly alternative to concrete: “It behaves like ceramic, is heat and water resistant.” And above all, it can be obtained from slag, i.e., industrial waste products. “That's where we want to go,” says Keller.

Any shape is conceivable

In terms of shape, the TUHH team has developed insulation elements into which various functions can be integrated – for example, there is space for pipes. “This could be a downpipe for rainwater, for example, or an electrical cable,” says Keller. We have lots of ideas about what can be integrated." Even though straight panels are currently being used, which can be mounted on a straight, vertical facade, any shape is possible in principle.
The idea of tailoring a building's insulation to its specific requirements is interesting from both an economic and an ecological perspective. When Styrofoam panels are cut to size, as is currently the norm, waste is always produced. “You can expect ten percent waste, which is a huge loss of material.” But if the facade could be printed to fit exactly, “there would be virtually no waste.” Keller compares the principle to a good tailor: “They tailor a jacket for me, and it fits me perfectly.” The extra costs for the good tailor, i.e., the 3D process, need to be offset by waste reduction and recycling. Or, as Maximilian Keller puts it: The goal is a process that is “simple, sustainable, and recyclable.”