The Grade II* listed great barn will open on Tuesday at Great Dixter in Northiam near Rye, the former home of horticulturist Christopher Lloyd.
It is one of the South East’s largest surviving medieval timber framed barns.
The barn and brick-built oast houses were restored as part of an £8m, four-year conservation project.
Work on the great barn by local craftsmen included repairs to rotting timbers and decaying joists.
Key features such as the remains of a cattle feeding trough and the threshing floor have also been preserved with the help of a Heritage Lottery Fund grant.
Repairs were also made to the original medieval house and a ground source heat pump and biomass boiler for heating were installed.