1775 - 1780
The Dolphin House built in the style of Robert Adam, 300 metres south of the castle to serve as a laundry, on the site of a natural spring.

1837 - 1901
Very busy castle laundry during Victorian times.

1945 - 1981
Fell into disrepair and partially restored as a dwelling house.

1996
Stonework badly in need of restoration, funding sought from Historic Scotland. The National Trust for Scotland chose to restore the building as a Outdoor Education base to that of Victorian Laundry Museum.

1997
Feasibility study carried out by South Ayrshire Council and partnership develops.

1999 The building work commences.

2001 Dolphin House is opened on 11th May 2001 by Cllr Elizabeth Foulkes, Cllr Sadie Bowie and Charlie Dimmock from the BBC's Ground Force. Holmston Primary, School, Ayr are the first residents.