Balneum project – Roman bathhouse virtual reconstruction

The virtual reconstruction of a 3rd century Roman bathhouse in Apulum, Roman Dacia

The time has come to share with you a new project I’ve been working on for a few months now. For this post, I invited as a guest dr. Anca Timofan, Balneum project coordinator, to write a few words about the context and the particularities of a hypocaust.

Let’s go!

Context

About the digging site

“In the years 2022-2023, an extensive preventive archaeological research took place in the Roman site of Apulum on the area where the “Altip” printing house in Alba Iulia used to operate. The archaeological discoveries were made in the civil settlement (canabae) of the 13th Gemina legion’s fortress, which received urban status during the reign of Emperor Septimius Severus (193-211 AD).

For archaeologists it was an extraordinary opportunity to research almost entirely a Roman house in the city of Apulum, to investigate stratigraphically the phases of habitation and how the property evolved and expanded over time. The identification of new streets, i.e. Roman properties, facilitated a better understanding of life in the ancient city below Alba Iulia in the 2nd-3rd centuries BC, by investigating this residential area gradually occupied by the dwellings of wealthy Roman families.” (dr. Anca Timofan)

What is a hypocaust?

“The Romans invented the most elaborate ancient underfloor heating system, called the hypocaustum. It was a true innovation, both in the technical field and in terms of comfort, which appeared at the end of the 2nd century/beginning of the 1st century BCE. It was a central heating system that generated and circulated hot air under the floor of a room, heating the walls with the help of ceramic tubes through which the hot air passed.

Archaeologists have discovered furnaces (praefurnia), small columns that supported the floor slab (pilae), the floor under which the hot air circulated, as well as specific elements of the hypocaust such as bricks, the so-called tegulae mammatae, box flue tiles, and more. This demonstrates how practical and inventive the Romans were, and today we continue to technologically improve and perfect these ancient construction systems. The emergence, development, and standardization of the hypocaust system improved the hygiene and living conditions of people in the past, making it a precursor to modern central heating.” (dr. Anca Timofan)

Research and documentation

Following my experience with Kore Formacion’s courses in any historical reconstruction project, we start with what we have. In this case, “what we have” is the archaeological evidence: the unearthed walls and objects.

The primary source of information was the digging itself. The whole archaeological site was digitized by aerial and terrestrial photogrammetry (dr. Călin Șuteu). The data extracted from the 3D data allowed the drawing of the bathhouse planimetry.

Many of the objects discovered on site were already digitized in 3D and available on the Sketchfab MNUAI collection. These were instrumental in modeling the details of the bathhouse.

The next step is to document what we have lost. This was the most time-consuming stage. As this building was just discovered there were no previous publications, photographs, or drawings. Being a civil building, of course, there were no mentions in historical documents. In this case, we investigated all the documented analogies discovered from the same time frame with similar construction similarities.

A very good source of information was the real-life reconstructions from Carnutum (Römerstadt Carnuntum, AU), especially the photographs from dr. Anca Timofan’s personal collection. Other important analogies were drawn from the Hadspen Roman Villa Museum (UK), Chedworth Roman Villa (UK), and of course, some of the objects were inspired by Pompeii and Herculaneum (IT).

The Bathhouse reconstruction

Once all the necessary documentation was accounted for, the next stage was to determine what was actually to be rebuilt. The goal of the project was to rebuild only the rooms with the hypocaust, not the whole house. An important decision at this stage was the purpose of the reconstruction as it would have dictated different approaches. In our case, the purpose was to create 2D illustrations that can be either printed or used online for educational purposes and technical explanations.

In virtual reconstruction projects, it is important to decide right at the beginning whether you want to model the interior or the exterior of the building, or both. In our case, we decided on both as we wanted some of the illustrations to have a cut-out design for a better understanding of the heating system.

Moving on, the next decision that had to be made was the level of detail we wanted to go for. As we had evidence for many objects and construction elements we decided to include them and go for a higher level of detail. To add to the realism we opted for a few male characters (that were bought, not modeled during the project).

Hypothetical structural elements

One last detail that needed to be established was the heights and roofs of the structure. As the archaeological evidences left us only the lower parts of the building foundation, as it usually is the case with buildings from this period, we had to estimate. Based on the width of the wall and its composition we made an estimation of the wall’s height and the roof structure. We knew the tegula and imbrex sizes from the archaeological finds so we could calculate the total weight of the roof and the wooden structure needed to support it. The roof shape and structure are hypothetical.

Another hypothetical assumption we made was the windows’ shape, size, and position. Based on the house structure the west wall was our best candidate. Finally, we designed the shape and size of the windows based on analogies with Carnutum.

Archaeological evidence scale

Last but not least, the utmost important aspect of historical reconstruction is the transparent discrimination between archaeological evidence, educated hypothesis, and imagination. All these elements are necessary for recreating a realistic yet as accurate possible lost scene. This transparency is ensured by using an extremely useful tool, the Archaeological Evidence scale. The evidence scale model used in this project was developed by Pablo Aparicio Resco and César Figueiredo (2017).