West Block, Parliament Hill

West Block is one of three buildings on Parliament Hill in Ottawa that comprise the original Federal Capital complex. Constructed in a mid-19th-century Neo-Gothic style, it is built of load-bearing mass masonry faced with local Nepean sandstone, accented by Berea sandstone sculptural and dressed stones, Potsdam sandstone trim, decorative red-granite shafts, and silver-green slate louvres. The building was raised across three major construction phases — 1859–65, 1875–78, and 1905–09 — followed by several comprehensive renovation campaigns.

West Block underwent an extensive multi-year rehabilitation. Alongside comprehensive conservation of the exterior masonry and sculptural elements, the building received a structural and seismic upgrade, full replacement of building systems, and an infill of the courtyard to house the interim House of Commons. Our team was contracted to provide conservation oversight for implementation of the exterior masonry program, completed in 2016.

Overseeing the exterior conservation, our conservators worked with a highly skilled masonry firm and the architect's consultant team to assess each individual stone, establish the extent of dismantling and rebuilding where required, and define repairs, replacement stones, cleaning, and repointing. A significant portion of the work entailed documentation of masonry conditions before, during, and after the work.

Numerous tests informed the program, including in-situ and laboratory laser-cleaning trials, analytical testing to identify metallic stains, saturation tests to observe the swelling behaviour of clays inherent to the sandstone, and one of the most extensive strength-and-absorption testing regimes undertaken to evaluate the appropriateness of ethyl-silicate consolidants.