This bracketed double staircase was commissioned from the London Marble & Stone Working Company, which had supplied the two colossal chimneypieces and door surrounds for the new entrance hall on the first floor in the mid-1830s. David Hamilton's initial designs were developed by William Field, the superintendent of the company, and the parts were shipped up to Hamilton (via Leith and Port Dundas) between 1840 and 1845, at a total cost of over £9,000.

The first-floor passageway appeared to be supported by two huge bronze male figures, which are referred to as caryatids (female figures) in the contemporary correspondence but are actually atlantids (after Atlas, who carried the world on his shoulders). They were ordered from the Parisian founder Louis Soyer and cost over 34,000 francs in 1842. Much of the black marble staircase has been acquired by the Museums of South Lanarkshire, but the atlantids are said to have been melted down.