From the galleries to the springing of the window arches, the walls of the House of Commons Chamber are sheathed in Tyndall limestone from Manitoba, with a Missisquoi black marble base from the Eastern Townships of Quebec. The same materials are used for the elevations of the public galleries located at the north and south ends of the Chamber.
Tyndall limestone was specially selected by architect John A. Pearson for the richness of its texture and its vibrant colour. Freckled with brown spots caused by fine fern markings, it is both handsome and extremely durable. The Tyndall limestone has been supplemented by large blocks of Indiana limestone, which was used for fine sculptural work.
The stonewalls, together with the stained glass windows, imposing pier-arcades and glazed tracery screens, are a prominent characteristic of the Chamber's grand design. Refined architectural details - such as moulding enrichment, slender shafts, blind tracery and friezes - were added to enhance the wall decoration. These elements, combined with an elaborate sculpture program, highlight the pre-eminent role of the Chamber in the House of Commons.
Approximately 225 rough blocks of limestone of different sizes - from tiny bosses to high reliefs reaching nearly two meters - were left uncarved in various locations throughout the Chamber. Interestingly, the Commons Chamber was the last room in the Parliament building to be transformed by the sculptor's chisel. It was not until the end of the 1950s that stone carving began in the Chamber. The first sculptures, consisting of corbels and brackets of early English foliage, were designed by sculptor William F.K. Oosterhoff, in 1958. Twenty years later, sculptural work resumed: this time, under the Dominion Sculptor, R. Eleanor Milne.