The Bath House was built about 1748 for Sir Charles Mordaunt of Walton Hall. Like many of his contemporaries, Sir Charles enjoyed making alterations and improvements to his house and estate and took a fashionable interest in architecture. He was one of the local circle of gentlemen connoisseurs and amateur architects, which included Lord Lyttleton of Hagley, Sir Roger Newdigate of Arbury and not least, his good friend Sanderson Miller of Radway.
Almost certainly it was the last of these, Sanderson Miller, who provided designs for the Bath House. The building bears a close resemblance to his known works, such as the Shire Hall in Warwick; and he had a particular fondness for rooms of octagonal form, as here. No drawings exist, but in October 1749, Miller noted in his diary that he was settling 'accounts with Hitchcox about Sir Charles' Bath.' William Hitchcox was both Miller's stonemason and his valet. Since he seldom worked for anyone else, his involvement at Walton provides some firm evidence for attributing the design to Miller.
Since Classical times, exotic buildings have formed an important part of garden design. In the landscape gardens of the 18th century these were carefully placed to appear unexpectedly in the course of meandering walks, sometimes chanced on close to, sometimes glimpsed from a distance, adding interest and variety to the scene. On a practical level, such buildings provided shelter, and a place to enjoy the view, take a rest and have picnics. Along with temples and towers, bath houses were also popular, having strong associations with the Classical past, and the baths of Ancient Rome. They served moreover a double purpose.
At that time people took a bath mainly for medicinal reasons. We know Sir Charles suffered from gout and his doctor would certainly have advised him that a cold dip would be beneficial for this ailment. A cold bath was also held to calm the nerves, improve digestion, invigorate the spirits, and even help to retain 'an equal bodily weight.' Lengthy immersion was not advised, in case it resulted in a 'Horror!'
The elegant octagonal room above the bath chamber is dominated by the plaster icicles, or stalactites, and the shell-work festoons, a refinement of the cave-like grotto below. It seems that this decoration was the idea of Mary Delany, whose sister Anne Dewes lived at neighbouring Wellesbourne Hall. Mrs Delany is better known for her paper flower pictures, but she also excelled in shell-work. She decorated her own home near Dublin in this way, and also possessed an impressive shell collection. She sent a barrel of shells to Walton in 1754, and probably helped in their arrangement, supervising her sister and Sir Charles' daughters.
Having served as the setting for many picnics and tea-parties, and even a Victorian dinner to celebrate a christening, the Bath House finally fell out of use after the Second World War. Efforts by its owners to keep it in repair proved unequal to the destructive energy of vandals. Eventually it was brought to the attention of the Landmark Trust and a lease was signed in 1987.