The remarkable archeological find of a Roman bathhouse with its timber-piped springwater supply still running intact means no delays to the £4.8 million development of an extension to The Sixth Form College in historic Colchester, according to the town's archaeological trust.

As the client college specialises in archeology courses, according to main contractor Higgins Construction PLC, there is no problem appreciating the value of such a rare find. Finding water piping timbers in such good condition is so rare that Colchester Archaeological Trust hopes to return later to excavate more of the site where a sports field is located.

Archaeologist Ben Holloway thinks that the bathhouse was attached to a villa between late-first and early 2nd Century AD, whose tessellated pavement in red mosaic was found 18 months ago by the side of the college sports pitch. It is believed the college grounds occupy 10 per cent of the Roman town's 100 acres, which exposes what is Britain's oldest town wall dated around 65-80AD. After needing to refill the bathhouse in preparation for the college extension, Howard Brooks is now leading the archaeological trust's excavation of a 2mx2m trench to research through remains of a Roman rampart constructed against the rear of the wall in the second century. It is thought wooden piles were used by the Romans to cope with water-logged ground conditions and that would mean being able to date the construction more precisely than ever from the tree rings.

Colchester Archaeological Trust expects its excavations to be complete within six weeks for Higgins to begin their own site preparations for the new college extension at the end of July. The extension is designed by the Roff Marsh Partnership architects. Fleuty & Robinson are the QS consultants.