Romans 6: hypocaust What once flowed between the pillars? Expand Not water, but a load of hot air! This photograph shows part of the hypocaust (underfloor heating system) at Folkestone Roman Villa. A charcoal furnace was lit by a slave on the far side of the arch. Hot air from the furnace passed through the arch and between the columns, heating the floor above (now missing). This villa had all mod cons, the height of Roman sophistication. This photo was taken in 1924, shortly after the villa had been excavated by archaeologists. What’s this? Expand The hot air also passed through hollow box flue tiles in the walls like this one. This helped warm the walls as well. What are these patterns for? Expand Some box flue tiles were covered in patterns, impressed into the clay with a wooden tool or roller while it was still damp. Sometimes the name of the tile maker is included in the pattern. These patterns weren’t just for decoration. They gave extra grip, when the tiles were cemented in place. These three fragments are from Folkestone Roman Villa.