A spider-shaped construction robot named Charlotte is being developed in Sydney with the ambition to 3D-print a full-size home in about 24 hours. According to its creators, the mobile system can autonomously build structural walls for a roughly 2,150-square-foot house using locally sourced materials.
Instead of relying on cement, bricks, and long supply chains, Charlotte compacts sand, soil and clean waste directly on-site. Researchers say this single-machine approach eliminates several carbon-intensive steps traditionally involved in construction.
Designed as a legged, highly mobile robot, Charlotte combines field robotics with additive manufacturing, forming structures layer by layer. The prototype demonstrated in Sydney is still under development, but its architecture points clearly toward the future of automated building technologies.
The project is led by Clyde Webster, founding director at Crest Robotics, whose work focuses on agile robots capable of performing construction tasks that are repetitive, difficult, or hazardous. The momentum behind the project stems from a global housing shortage and growing pressure to reduce carbon emissions.
“The building materials we use today—even a simple brick—go through several stages, many of which are highly carbon-intensive,” said Dr. Jan Golembiewski, co-founder of Earthbuilt Technology.
Crest’s system collects sand, earth, and crushed brick beneath its frame, binds the mixture in textile layers, and compacts it into successive courses. At the heart of the process is extrusion—the controlled flow of material through a nozzle—allowing walls to be produced continuously without mortar joints and guided directly by digital building plans.
“It will work at the speed of more than 100 bricklayers,” Dr. Golembiewski said, highlighting the emphasis on both speed and simplicity.
Its multi-legged design also enables the robot to move across uneven terrain where wheeled machinery struggles. A compact, folding frame further eases transportation, which is critical for remote or hard-to-reach sites.
Cutting Carbon in Construction
The construction sector is a major contributor to global emissions. A UN Environment Programme report notes that in 2022 the industry accounted for 37 percent of energy- and process-related carbon dioxide output.
Reducing emissions at the earliest stages of construction has a disproportionate impact, making embodied carbon—a measure of the emissions generated during material production and transportation—a key focus for regulators. Charlotte’s developers say their method eliminates the use of cement altogether while converting clean waste into durable building material. If proven through safety and performance testing, it could slash both costs and emissions on the same project.
There is also a workforce dimension. Automating physically demanding and repetitive tasks may help reduce injuries and allow smaller crews to focus on skilled work.
Impact on Labor
While robotics could help address worker shortages in some countries, they also raise concerns about job displacement in regions where construction work provides essential livelihoods. Analysts warn that widespread automation could widen income gaps between designers, operators, and traditional laborers. Others argue that a balanced approach—where robots support rather than replace skilled workers—could enhance productivity without removing human expertise from the jobsite.
Regulatory and Technical Challenges
Any new structural system must undergo rigorous testing, including load performance, fire resistance, flood durability and quality control assessments. Early deployment is expected to focus on low-rise buildings, where regulatory pathways are clearer. Jurisdictions will also dictate how and where such robots can operate safely around people.
Material consistency is a crucial challenge. Soil and waste vary from location to location, making calibration essential. Developers say digital mixing “recipes” can adjust in real time, though independent testing will be necessary to verify performance against established standards.
Potential Beyond Earth
Charlotte’s lightweight, foldable design has also drawn interest for off-world construction. Concepts developed by AI SpaceFactory and NASA outline strategies for shielding lunar structures, including self-shading forms and a 2.7-meter layer of lunar regolith to guard against radiation and micrometeoroids.
Lunar regolith behaves differently from Earth soils due to vacuum conditions, low gravity and extreme temperatures, meaning any 3D-printing system would need to adapt accordingly. Laboratory studies have shown that regolith-based geopolymers can achieve structural strength suitable for protective shells and pavements under controlled conditions, pointing to possible pathways for future lunar construction.
