What can we learn from Roman flue tiles?

Roman flue tile
Roman flue tile

Back in December Cotswold Archaeology invited applicants for a sponsored PhD in the field of Roman Ceramic Building material (CBM). We’re excited to announce that sponsorship was granted to Joseph Locke, whose proposed research will contribute to the wider understanding of Roman flue tiles. We have interviewed Joseph to find out more about his research plans…

Interview with Joseph Locke

CA: Hi Joe, congratulations on your PhD appointment, please could you tell us a little bit about yourself?

JL: I studied Classical and Archaeological Studies at the University of Kent for my undergraduate degree, graduating in 2013. My undergraduate dissertation looked at prehistoric Minoan pottery typologies on Crete, and this is what first developed my interest in ceramics. I later studied for my Master’s degree in Classical Archaeology at the University of Oxford. Since graduating from my master’s, I have been working as a field archaeologist in the UK for a number of commercial companies.

I will be studying for the PhD at the University of Kent, starting in May this year.

CA: How did you get interested in CBM?

JL: I first encountered CBM whilst excavating on Romano-British sites as a field archaeologist and by volunteering at museums. Through this contact with CBM I became interested in questions relating to how the CBM might have been produced and used.

One of the most fascinating things about CBM is its potential to help us understand the organisation of the Romano-British construction industry and to shed light on aspects of Roman society and economy in Britain.

CA: What is the subject of your PhD and how are you going to research it?

JL: The type of CBM that I will be studying are flue tiles. Flue tiles were a specialist type of tile that allowed the circulation of hot air through the walls of a hypocaust system and were used in bath-houses and heated rooms. They were introduced by the Romans to Britain in the 1st century AD, following the Roman conquest. There is a wide variety of flue tiles present in Britain.

Many characteristics of flue tiles show variations which can be studied. One characteristic of flue tiles are the keying marks on their surfaces which were designed to help mortar or plaster stick more securely to their surfaces. There is a wide variety of both keying methods and patterns, with some flue tiles having simple cross-hatching scored into their surfaces, whereas others show more elaborate patterns that were applied using a roller die – these are called relief-patterned dies. Flue tiles have vents cut into their sides which allowed air to circulate laterally, and there is variety in the shape and number of these vents. There is variety in the basic shapes of flue tiles, the most frequently occurring being the ‘box’ shape. Flues tiles also come in a large range of different sizes.

By investigating these variations, this PhD hopes to develop our understanding of flue tiles and build on research that has already been done. The most researched aspect of flue tiles are the relief-patterned dies. There is potential to develop the work already done and incorporate other less studied aspects of flue tiles into the research.

Hypocaust discovered at Cannington Bypass, Somerset
Hypocaust discovered at Cannington Bypass, Somerset

CA: What can we learn from Roman flue tiles?

JL: This research into flue tiles aims to shed light on aspects of their production, use, and development.

One aim of this research is to develop our understanding of who the producers of flue tiles were and how they were organised. One way that this can be investigated is by looking at the relationship that different varieties of flue tile had to each other when they are found at the same kiln site or the same consumption site. Interesting flue tile distribution patterns in some regions of Britain will be investigated, which should also shed further light on our understanding of the organisation of the industry.

The research will aim to help us understand the uses of flue tile in different building types, and in different types of hypocaust. Part of this investigation will also look at the changing relationship between box flue tiles and some different types of early CBM that were also used in hypocausts to create wall cavities. This might develop our understanding of how Roman engineers and architects experimented with different approaches to hypocaust heating.

This research may also be able to help us to understand how and why the different flue tile types developed, whether for example this was in response to technological developments in hypocaust design or perhaps in response to other factors. Interesting relationships with other provinces may be found, as ideas and skills will have been travelling back and forth across the channel.

CA: What is your plan for the first months of your research?

JL: The first few months of research will be spent reading about flue tiles and CBM. I will be doing this before I begin viewing and studying the flue tile, which will help me approach the material in the best way possible. I am looking forward to reading some interesting studies of Roman CBM, including publications on early thin-walled flue tiles and on relief-patterned keying.

Early on, and as my research progresses, I will be meeting with Dr Peter Warry who is a Roman CBM specialist, and who will provide guidance and assistance.

The research will involve visits to museums to study their archived CBM. I will be updating CA regularly on my progress.

CA: Thank you for sharing this with us. We look forward to hearing more about your discoveries as the research progresses.

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