NOVA's bath, like hundreds of Roman baths before it, is
crowned with a vaulted roof, another Roman innovation. Before
them, the Greeks built temples and other large buildings by
supporting large flat roofs with many columns.
The Romans improved on the design, building curved roofs with
a keystone dropped into the top of the vault. The downward
thrust of the keystone pushed the sections outward, creating a
pressure that held the entire roof together. The curved roof
makes the columns unnecessary, freeing the interior space of
its weighty columns.
NOVA's vaulted roof is built of bricks. A tense moment during
the bath's construction comes when the wood form underneath
the vault is removed. If the vaulted roof isn't built
correctly, it would cave in when the wood forms are removed.
Lucky for all, the roof holds.