Conservation Solutions, Inc: Art + Architecture + Artifacts

West Block Masonry Conservation - Parliament Hill

Site
Parliament Hill, Ottawa, ON, Canada

The 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, West Block is constructed of load-bearing mass masonry and faced with local Nepean sandstone, accented by Berea sandstone sculptural and dressed stones, Potsdam sandstone trim, and decorative pink granite shafts. The building had three major construction phases; 1859-65, 1875-78 and 1905-09, as well as several comprehensive renovation campaigns.

West Block is currently undergoing an extensive five-year rehabilitation project. The work is largely comprised of modernizing and reprogramming interior spaces, including an interim House of Commons chamber, set to occupy the courtyard which will be enclosed by a glazed roof. Conservation of the exterior masonry represents an equally large and significant part of the work. Conservation Solutions (CSI) was contracted to provide conservation oversight for the team implementing this work.

Overseeing the exterior conservation, CSI 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 of deteriorated areas of masonry when required, define repairs and/or replacement of the Nepean, Potsdam, and  Berea stones, as well as the decorative facade elements, cleaning, and repointing. A significant portion of the work entailed documentation of masonry conditions before, during and after work as well as a final conservation report of all completed masonry work.

Numerous tests were performed, including laser cleaning of the masonry, analytical testing to identify metallic stains, saturation tests to observe the swelling behavior of clays inherent to the sandstone, and one of the most extensive strength and absorption testing regimes to evaluate the appropriateness of the use of ethyl silicate consolidants.