A student publication series by the UNCG Department of Interior Architecture

Enter the 3rd Dimension with 3D printing

By J.G. Adams, IV

If you have ever worked on a historic rehabilitation project you know that sourcing damaged components can prove quite difficult and time consuming. The missing or damaged baseboard or crown molding has not been manufactured in years. The picture of the original home shows a plaster medallion around the dining room chandelier but the dining room you are working in only shows ghost lines of the medallion. The decorative concrete work on the exterior of a commercial two-part block building has been sandblasted and is deteriorating to the point of crumbling sand. What are you to do? It is time for historic rehabilitation to travel into the third dimension with 3D printing.

Brief History of 3D Printing

Seemingly a new technology, talk of three dimensional (3D) printing actually started back in the 1970’s. It was not until 1981 that the first patent for 3D printing was obtained by Japan’s Hideo Kodama. Kodama’s invention used UV light to harden photoreactive polymers or in simpler terms, light activated resins. The idea behind this technology was that it would be useful for creating prototypes and models.

The original 3d printing machine by Chuck Hull.
Fig. 2: Chuck Hull’s original 3D Printing Machine

Chuck Hull is considered the father of 3D printing. Kodama invented the system before Hull, but it was Hull who came up with the machine and named the process and filed for his patent in 1984. Hull also developed the STL file format (Standard Triangle Language or Standard Tessellation Language) which is the digital file that can be read by the 3D printing machine. In 1986 Hull named this process stereolithography (SLA) and it remains one of the most widely used 3D printing techniques today.

In 1989, S. Scott Crump patented the Fused Deposition Modeling (FDM) method. FDM is completely different than SLA in that it takes a cable of thermoplastic material and is run through a heated nozzle controlled by a computer, that extrudes the liquefied material in layers to create the 3D component. While commercial projects are using this process, it is typically the process seen used in a residential or DIY 3D printing scenario.

Large, industrial sized 3d printing machine.
Fig. 3: Industrial 3D Printing Machine Used to Print Large Objects 

Typical Methods of Recreating and Restoring Historic Building Components

The Secretary of the Interior’s (SOI) Standards for Rehabilitation items 5 and 6 state: “(5) Distinctive features, finishes, and construction techniques or examples of craftsmanship that characterize a property shall be preserved” and “(6) Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials. Replacement of missing features shall be substantiated by documentary, physical, or pictorial evidence.” There is a sidebar in the SOI Standards that states: “The Standards are to be applied to specific rehabilitation projects in a reasonable manner, taking into consideration economic and technical feasibility.”

Inevitably, historic buildings will need damaged and deteriorated parts to be addressed. Whether it be water intrusion, ultraviolet light or any other number of factors, an old building needs maintenance and repairs. If possible, it is best to use historic materials in the process of repairs. The properties and appearance of the historic materials should be matched as closely as possible to the existing building being careful not to damage the original components during the process.

The SOI sidebar noted above appears to open the window for the use of 3D printing to assist in the rehabilitation of historic buildings by “taking into consideration economic and technical feasibility.” The use of 3D printing has the potential to ease economic constraints as well as technical feasibility.

Missing or damaged wood trim, whether interior or exterior, always seems to find a spot on the list of repairs and maintenance. In a historic building, it is highly unlikely that you will find the same wood trim profiles at your local lumberyard or big box store. Sometimes extra trim pieces can be found in the attic, basement, carriage house or garage.

What do you do when there are no extra pieces or not enough trim components for what you need? There is a possibility that you may find something close at your local lumberyard that, with a bit of customization, can bridge the gap between old and new. While that might get one through who does not realize the importance of historical integrity, the real solution is to have new pieces milled that exactly match the originals. This is an expensive, tedious and time consuming process.

What do we do with deteriorated decorative concrete on a commercial building or home? First, an analysis of the concrete must be conducted in order to recreate the correct mix for the repair. Once that is established, the tedious process of filling and recreating these decorative concrete components begins. The largest expense for these repairs is not materials, it is labor. The labor to conduct this type of repair compounds itself in relation to the size of the project. The larger the project the larger the expense.

Recreating or reconstructing damaged or missing building components is a tedious and labor-intensive process. Additionally, there are fewer and fewer craftspeople that are knowledgeable in historic rehabilitation. While a machine will never be able to match the hands of a talented craftsperson, it may prove that in some circumstances, the machine cannot be matched for total project economics and time savings.

3D printing machine for small to medium sized projects.

Fig. 4: DIY 3D Printing Machine Used to Print Small to Medium Sized Objects 

Could 3D Printing Be a Valuable Tool in Historic Rehabilitation?

Rehabilitation costs of historic buildings have dramatically increased as the number of talented and skilled craftspeople has diminished. The labor force that originally created the highly ornamental decorations of historic buildings has given way to the sleek design of modern materials and an interest in building structures for the least amount of expense as possible. The ornamental building has given way to simple lines and smooth fabric for the sake of a more affordable budget.

Many of the highly ornamented historic buildings are being demolished because the expense to rehabilitate them seems much too great. These representations of architectural styles are erased and hauled to the landfill for the sake of “progress”. With the developments of 3D printing come the possibilities of rehabilitation and repairs at an economic level that more people will be able to see the benefit in saving the building rather than demolishing it.

3D printed molds and masonry components.
Fig. 5: 3D Printed Molds and Masonry Components 

In the masonry trades, 3D printing firms are now able to create complex molds to cast replicas of parts needed to rehabilitate historic buildings. Designers can scan any portion or part of the building and its texture data into their 3D modeling software. After the design information has been processed, a strong 3D mold of the component can be 3D printed. This mold is then coated with a bond breaker, inlaid with wire mesh or rebar and cast with concrete, plaster or other masonry materials. In some instances, depending on the size of the component, the printing and casting process can be completed in a day or less. This design can then be saved and catalogued to be reprinted at anytime it is needed in the future.

This same method can be used for wood repairs. Decorative wood trim, interior or exterior, whether it be around a fireplace, column or window sash can be restored through the use of epoxy resin or other synthetic materials. In the same method used for masonry repairs, scanning the component and its texture data into their 3D modeling software, molds can be created. Once the mold is created, it can be cast with epoxy resin or other synthetic materials and once cured, installed with minimal labor costs. Depending on the size of the component and scope of work, the part itself could be 3D printed eliminating the need for a mold. These designs can also be saved and catalogued for future use. It should be noted that it would depend on the scope of the project and the structure itself whether or not creating synthetic trim pieces to match the original wood pieces would be justified or an acceptable substitute.

3D printed mold with wire mesh for support.
Fig. 6: 3D Printed Mold With Wire Mesh for Support

As we move forward, the relationship between technology and craftsperson is surely going to grow more closely together. The nature of this relationship has already undergone significant changes by the tools used to originally produce the building to the tools that we use rehabilitate and maintain it with today.

Originally, 3D printing started out as a way to design small objects or prototypes. More recently, we have seen large scale projects using 3D printing including a whole house. Artisans and craftspeople will hopefully see the benefit of using digital tools in new ways to express their craft as it could become another tool in their toolbox to aid in the perfection of their work.

The technology of 3D printing contains many solutions in historic rehabilitation. Having the ability to scan any component of a building is monumental when saving time and energy in recreating damaged and missing components. The molds that are created by 3D printing are of exceptionally high quality and produce less waste than other technologies. Rather than crafting these pieces by hand, 3D printing proves to be a much more efficient process.

3D Printing as an Assistant in Historic Rehabilitation Projects

Architects are using 3D printing to perfect their building designs, improve communications with builders or clients and save time when presenting their ideas. The models that they create using 3D printing will later become the actual buildings that they have designed.

3d printed sale model of Notre-Dame
Fig. 7: 3D Printed Scale Model of Notre-Dame 

Submitting paper plans/blueprints are mandatory for any building project whether it be new construction or rehabilitation. While blueprints are extremely helpful and what has been used in the past, 3D models help with the conceptualization of the project. The more details that are in paper plans the better and there will be less questions concerning design. Yet, there is still only so much that one can grasp from a flat sheet of paper. 3D printing gives the project a multi-dimensional perspective of the space as well as avoids some of the confusing aspects of the project.

Gargoyle at Notre-Dame overlooking Paris
Fig. 8: Gargoyle at Notre-Dame Overlooking Paris 

On PBS’s “This Old House” 3D printing was used on their 2013 Essex show. A model of the home was created using 3D printing. It had removable parts to allow an exterior as well as interior view of the home. This helped the builders and trades people envision the final design and, in this case, fully understand the complicated roof details prior to driving the first nail or cutting the first board. This model proved effective in saving time and money in that a full understanding of the project was seen in 3D rather than two dimensional blueprints.

Reconstructing Notre-Dame is another way that 3D printing is proving to be quite a useful tool. Full scaled 3D models of Notre-Dame have been created to assist with the restoration after the fire on April 15, 2019. This offers the ability to conceptualize the project through a full visualization rather than relying solely on blueprints.

While a structure such as Notre-Dame would be better served using components that are created by hand, 3D printing offers the craftspeople an option of using 3D models to assist them in their work. With a 3D model, whether it be scaled or actual size, full views of the object being recreated can be seen without having to remove them from the structure. Take the gargoyles that surround Notre-Dame. Rather than removing one or having to climb up to view one for details, a 3D scan and print of the gargoyle and its textures can create a 3D model to assist the craftsperson constructing it.

Capitals created by 3D printed molds.
Fig. 9: Capitals Created by 3D Printed Molds

Some would argue that using 3D printing to rehabilitate a building is not authentic. Understanding that in some cases traditional tools will provide solutions modern tools cannot, when rehabilitating a historic building today, we are typically not using handsaws – we are using a circular saw or miter saw. We find ourselves using pneumatic nail guns rather than an actual hammer to drive nails. A power planer is often used to plane a board rather than a hand planer. We are using the technology that has been developed over years of advancement. The same argument can made for 3D printing. That we are using the technology that has been developed to assist us with rehabilitating historic buildings.

The fire at Notre-Dame was indeed a tragedy, but as tragic as it was, it offers a chance for the technology of 3D printing to prove its merit in assisting craftspeople rehabilitating historic buildings. It should never be assumed that 3D printing an entire object should take the place of an object created by the hands of a highly skilled craftsperson on a structure such as Notre-Dame, but 3D printing offers a chance to hurdle the obstacles and problems typically associated with rehabilitation projects. With Notre-Dame as an example, France has the ability to recreate a singular spectacle of medieval French Gothic architecture with the assistance of today’s modern technology.

Decorative concrete repair project.
Fig. 10: Decorative Concrete Repair Project  

Negative Aspects of 3D Printing in Architectural Rehabilitation

Many great aspects of 3D printing architectural components for rehabilitating historic buildings have been seen. There are also some negative aspects that need to be recognized as well such as availability of materials, reduction in manufacturing jobs and engineering compatibilities.

Materials that can be delivered through the printer head are limited to plastics/resins, metal and concrete. Components and structures requiring wood are not able to be completed using a 3D printer at this time. Some materials are not able to perform as needed in a 3D printing application by not having the characteristics that allow them to be temperature controlled and still be effective. Other materials are not able to be recycled which is another contributor to the limitations of 3D printing.

Capitals created by 3d printed moldes.
Fig. 9: Capitals Created by 3D Printed Molds

A potential reduction in human labor could be induced by the further introduction of 3D printing. Since 3D printing is automated, the amount of labor needed to create components for historic rehabilitation work would be limited. Manufacturing jobs could be put at risk with the further development of 3D printing as well as labor positions on a construction site. Since traditional blueprints are not compatible for use with a 3D printer at this point in time, some architects and engineers have not embraced the new technology. This would require a new phase of design thus creating an entirely new design process.

Whether 3D printing is economical or not depends on the size and scope of the project. Many factors must be taken into consideration when pricing a 3D printing project. The amount of filament used, the amount of time it takes to program the data for the printer to produce the object, the time it takes to print the object and the quality of the filament are all important factors in considering the cost of a 3D printing project.


3D printing is starting to take a vital role in rehabilitation projects in both structural and aesthetic characteristics. There is less of a chance for interpretation when a full scaled model of a project is on the table for builders and trades people to visualize. There is less room for error when recreating components when exact replicas can be created with 3D printing. Through 3D printing, the architect as well as builders and trades people are held accountable for their production. While the evolution of 3D printing continues, it will be extremely interesting to see how this positively affects the rehabilitation of historic buildings.

As we move forward and the technology of 3D printing advances, hopefully the knowledge of the professionals in construction and the highly skilled labor force will advance as well. In addition to learning how to use a hammer and chisel to recreate ornamental objects or a drafting table and square to design them, people will learn the programming methods and scanning techniques to create 3D models of historic buildings, along with their components, in the new age of architectural rehabilitation.


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Image Credits and Acknowledgements 

Fig. 1, Fig. 5, Fig. 7- photo courtesy of www.3-dprotototype.co.uk
Fig. 2 – photo courtesy of www.3dprint.com
Fig. 3 – photo courtesy of www.cati.com
Fig. 4 – photo courtesy of www.flashoforgeshop.com
Fig. 6, Fig. 9, Fig. 11- photo courtesy of www.3dnatives.com
Fig. 8 – photo courtesy of www.wanderwisdom.com
Fig. 10 – photo courtesy of www.kaptivecp.com

The Author Thanks the Following:
Jo Ramsey Leimenstoll for her unwavering support and guidance.
Colonel Christopher Vann whose insightful feedback mixed with infinite knowledge pushed me to sharpen my thinking and bring my work to a higher level.
The UNC-Greensboro Spring 2021 IAR 624-01 class for their help and patience.

The Historic Dimension Series is a collection of briefs prepared by UNCG students under the direction of Professor Jo Ramsay Leimenstoll. For information on other topics in the series please visit the website at www.uncg.edu/iar/hds