 The design of the building has a tapering cylindrical form, with the charging ramp being more rectangular in plan.In 2009, the lime kiln was designated Grade II.Historic England commented that it remains a "well-preserved and distinctive feature of the lime industry and an important survival on Portland" and is of "special historic interest for its location and association with Portland quarries and the prison's use of convict labour during the 19th century and the early 20th century".