The western side comprises two towers, rounded at the bases but corbelled out to square above the level of the basement.

[1] The armorial stone of the builder, Patrick Levingstoun of Saltcoats, is now mounted over the door of a cottage nearby.

[4] There is a lectern type dovecot, 17 by 15 feet (5.2 by 4.6 m), in the boundary wall of the castle.

The partly buttressed walls are built of rubble, with dressings and one setback course.

[5] A surviving oak bed at Biggar Museum, was made for Margaret Fawside of Fa'side Castle, who married Patrick Levingstoun of Saltcoats in 1598, and is carved with their heraldry.