It is a 'restrained neo-classical' ashlar mansion of three floors, with a separate and extensive stableyard and coach-house which was originally set in 93 acres of parkland.

The 1940s also saw a neo art-deco open-air theatre constructed at the back of the house, designed by Sir Lancelot Keay.

[2] The Reader, a national charity centred around literature and shared reading,[3] was given preferred bidder status in January 2013.

The redevelopment was completed in Autumn 2019 when it reopened as The Reader's International Centre for Shared Reading—the world's first public building dedicated to literature and wellbeing.

The Calder Stones now form part of The Calderstones Story, an interactive, permanent exhibition at the Mansion House that tells 5,000 years of local history.