3D Printing Beyond Concrete: Tools Work, Buildings Do Not Yet

Concrete gets all the attention, but polymer, composite, and metal printing have been pitched to construction for a decade. The useful question is which of it is production work with paying customers and which is still a research demonstration wearing a press release.

The short answer is that the genuine commercial win is not buildings at all. It is tooling.

The large machines are mold machines

Thermwood LSAM, Ingersoll MasterPrint, and the Oak Ridge BAAM platform get cited constantly in construction technology coverage. Their documented output is aerospace tooling and molds. CompositesWorld’s survey of all three describes them as primarily designed for aerospace tooling and mold fabrication, and contains no references to construction or architectural applications.

The verifiable Thermwood examples are a Boeing 777X demonstrator tool and the Al Davis Memorial Torch at Allegiant Stadium, which is a decorative architectural feature rather than structure. Ingersoll’s is a 22 foot helicopter rotor blade trim tool for Bell Textron, printed in 75 hours. Oak Ridge has used BAAM with the University of Maine and TPI Composites for wind turbine blade tooling.

If a source tells you these machines are used in construction, the fair question is which building. The answer is molds, tooling, and one stadium sculpture.

Printed formwork is the real commercial case

This is production today, with repeat customers, competing on cost against plywood.

At One South First at Domino Park in Brooklyn, Oak Ridge National Laboratory printed precast concrete molds in carbon fiber reinforced ABS with Gate Precast and Additive Engineering Solutions, partly funded by the Department of Energy. The printed molds proved faster to produce and more durable than conventional wood molds, and were economical where many identical castings were needed. After that project, Additive Engineering Solutions distributed the molds to numerous other US construction projects. That is commercialization rather than demonstration.

The strongest recent example is structural rather than decorative. In November 2025, three 42 foot concrete columns forming the bioshield for Kairos Power’s Hermes reactor were cast using printed carbon fiber reinforced polymer forms produced on Oak Ridge’s large format system. Each form was made of three pieces roughly 10 by 10 feet, held to a tolerance of one sixteenth of an inch.

The performance numbers are what matter. The printed forms carry a pressure rating of 20 psi against roughly one fifth of a psi for conventional forms, which allowed 8 foot pour lifts instead of the typical 4 foot maximum. The zigzag geometry required for radiation shielding was described as extremely challenging to produce with wooden molds. No quantified cost or schedule saving was published, so the engineering case is stronger than the financial one at this point.

Why does printed tooling work when printed buildings struggle? Because the printed object is a tool, not a building element. It never has to be code approved as structure, never touches AC509 or an evaluation report or a seismic provision, and it competes against plywood and CNC milled foam. Aerospace grade printed tooling survives roughly 20 to 30 cure cycles before rehab, so repetition pays for it.

Printed metal in buildings: read the status carefully

The MX3D stainless steel footbridge in Amsterdam is the most photographed printed structure in the world. It was installed in 2021 over the Oudezijds Achterburgwal under a two year City of Amsterdam permit as a research installation, with sensors and a digital twin as the actual deliverable and Lloyd’s Register Foundation as structural safety research partner.

It was dismantled in October 2023 when that permit expired. The historic bridge it spanned has been renovated and returned to service. The printed structure remains in MX3D’s possession awaiting relocation, and no confirmation of a new site could be found. MX3D itself has since raised 7 million euros and repositioned toward wire arc additive manufacturing systems for large industrial parts, maritime work, and art, rather than building structures.

Arup’s topology optimized printed steel nodes are the other example everyone cites. They were unveiled in June 2014, with a redesign achieving roughly 75 percent weight reduction, and later work shifted to printing sand molds for casting nodes rather than printing steel directly. All substantive coverage dates to 2014 through 2016, and no current Arup printed structural steel project could be found. Anyone presenting that work as current practice is recycling decade old press.

No building in service today with printed structural steel in its primary load path could be verified.

Composites: cladding, not structure

Branch Technology in Chattanooga is the one genuine producer in this category. Its BranchClad system is a rainscreen cladding built on a composite core of printed carbon fiber polymer matrix and robotically milled foam insulation. Named installations include the Tennessee Valley Federal Credit Union, the US Space and Rocket Center, and a parking garage in downtown Huntsville. The company completed what it describes as the first 3D printed commercial building envelope in the United States in 2021.

Two things a specifier should note. This is cladding, carrying its own weight and wind load only, not structure. And the company’s published material specifies no building code approvals or third party testing, so ask for NFPA 285 and ASTM E330 data before you spec it. No 2025 or 2026 Branch project news could be found, so confirm the company is actively shipping before you design around it.

The University of Maine’s BioHome3D, unveiled in November 2022, is the first fully bio based printed home, made from wood fiber and bioresin with Oak Ridge. It met its sustainability, strength, and durability goals under monitored exposure, and the same partnership has printed a recyclable floor panel. It is one demonstration house. Treat it as research with promise, not as a product you can buy.

The standards gap

This is the part that decides whether any of this reaches your project, and it is widely misunderstood.

AWS D20.1/D20.1M:2019, the Specification for Fabrication of Metal Components using Additive Manufacturing, is the real document for printed metal. It is a fabrication specification, not a structural design code. It governs how a component is made and qualified. It gives an engineer no allowable stresses, no load factors, and no design provisions. No AISC design specification for additively manufactured structural steel could be verified as existing.

For printed polymer and composite structural elements there is no US structural standard at all. Branch’s cladding cites no code approval and the University of Maine work is research.

So the practical path in 2026 for anything structural is the alternative materials and methods provision of the IBC, project by project, with an engineer of record accepting responsibility and a building official agreeing. That is the same route concrete printing took for years before AC509 and the evaluation reports existed. It is workable, it is slow, and it does not scale.

An honest scorecard

Status	What qualifies
Production today	Printed polymer molds and formwork for precast and cast in place concrete. Aerospace and wind tooling, though that is not construction
Emerging and marginal	Printed composite rainscreen cladding, a handful of named US buildings, no published code approvals, no verified current pipeline
Still research	Printed structural metal in buildings, printed bio based structural housing, and any printed polymer element in a load path

The pattern worth carrying away is that additive manufacturing succeeds in construction wherever it makes a tool and struggles wherever it tries to make the building. Tools compete on durability and geometry against plywood and foam, with no code authority involved. Building elements compete against mature, cheap, well understood systems and have to satisfy a code that does not yet have provisions for them.

If someone brings you a printed solution, the first question is whether the printed object is a tool or a permanent part of the structure. The answer tells you most of what you need to know about the risk.

Sources

Oak Ridge National Laboratory, precast molds for the Domino Park building
CompositesWorld, printed CFRP forms for the Kairos reactor bioshield, November 2025
CompositesWorld, large format additive machines and molds
Additive Manufacturing, printed tooling durability for precast concrete
VoxelMatters, MX3D bridge removed after permit expiry
Lloyd’s Register Foundation, MX3D printed steel bridge programme
MX3D, 7 million euro raise and industrial focus
Dezeen, Arup printed structural steel components, June 2014
Branch Technology, BranchClad system
University of Maine, BioHome3D unveiling, November 2022
AWS D20.1/D20.1M:2019, fabrication of metal components using additive manufacturing
3D Printing Industry, Ingersoll and Bell rotor blade tool

Keep reading

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