T8 was excavated through a series of modern make-up layers (L6, c.650mm thick) onto a redeposited dirty brown/grey clay (L7, c.700mm thick). At a depth of c.1.35m below modern ground level, L7 overlaid blue/grey alluvial clay (L3) which had the scars of a wooden revetment surviving it in (F11). No wood survived, just the dark outline where the wood had once been. The trench was too small and deep to allow for further investigation. Finds directly above F11 suggested it was covered over in the 19th century.<1>

The excavators suggested the revetment is probably associated with the 19th-century mill rather than an earlier structure (although dating is not certain) based on the following reasons:
1) the revetment is parallel to the standing building, approximately 3.3m away from the south-east wall.
2) In the only existing photograph of the mill that shows the waterwheel (taken in 1952), the wheel is shown housed in a timber structure, approximately 1.5m wide so it is feasible for the width of the wheel pit to be larger to accommodate the water from the overshot pipes and to aid in channelling it away.