In 1775 Pennant commissioned Samuel Wyatt to design what became the larger stone extension to the house.

In a possible attempt to harmonise the older part of the house with the stone extension, in the early 19th century the timber-framed wing was coated with roughcast and castellated.

Stanley's son, Edward, moved into the house in 1842, but left for Alderley Hall in 1850 after succeeding to the barony.

[2] For some years the hall was used as a girls' finishing school under Miss Margaret Alexis Bell and Miss Mary Jane Bell, where Sir Charles Hallé visited to give recitals and John Ruskin gave lectures.

[3] Ruskin helped the school financially, and had his own room in the house, which became for him a "semi-permanent residence".

[4] He instructed the 35 girls on subjects such as the Bible, geology and art, supervised their music, and watched them play cricket.

[a] In 1863 Ruskin invited Edward Burne-Jones to the school, and together they devised a project to create a set of wall hangings based on characters from Chaucer's poem The Legend of Good Women.

[3] The roughcast was removed from the older part, much of the timber was replaced, and the attic floor was abandoned.

After the First World War the building was converted for use as the Winnington Hall Club for the use of the staff of Brunner Mond.

[2] The building was restored in about 1920 by Darcy Braddell, who was responsible for much of the current internal decoration.

On the left side of the wing is a projecting canted bay containing sash windows.

Each of these bays is lit by a glazed lunette, below which are oval medallions containing a depiction of a neoclassical figure, and a niche holding a black basalt vase.

The Octagon contains a Neoclassical fireplace, a delicately decorated plaster ceiling, and a frieze of winged gryphons.