Cardiff Castle house contains the magnificent 19th-century interiors by the architect William Burges (1827-81), designed in the Gothic Revival style for the 3rd Marquis of Bute. These interiors are perhaps the most elaborate ensemble of nineteenth-century  decoration and ornamentation to be found anywhere in the country,. They were formed from the very the highest craftsmanship, with every surface intricately covered in painting on canvas and plaster, gilding, stained glass, carved timber and stone. The result is an extravagant Neo-gothic medieval fantasy, full of literary conceits and witty details derived from eclectic sources.

A highly ambitious project to conserve the Burges interiors was undertaken for Cardiff City Council between 2006 and 2007 by Paine and Stewart. At the time it was the highest value conservation project ever commissioned in Wales. The aim of the programme was to achieve a light and homogeneous surface cleaning level throughout all the 18 interior rooms. The project was awarded the RICS  Building Conservation Award in 2007.