West Block Rehabilitation Project

Parliament Hill, Ottawa 2016-2018


HPCS was originally retained by EVOQ Architecture (FGMDA at the time) to provide recommendations for preserving the heritage plaster in several areas of the building during the massive rehabilitation project. One of the key rooms under investigation was Alexander Mackenzie’s office and the ‘secret’ spiral staircase. The office was to be retrofitted with the up-to-date electrical, mechanical, and communication system in order to serve as the ‘temporary’ office of the current Prime Minister in anticipation of the eventual Centre Block Rehabilitation. The goal was to preserve as much of the original plaster as possible while carrying out the massive modifications.

The plain face wall plaster in the office and stairwell was in poor condition and delaminating from its wood lath substrate. If left untreated It would likely not survive the extensive modifications that were planned for the room. The right way to stabilize such plaster is to apply low viscosity consolidants to the back of the plaster where they can penetrate and strengthen the plaster system. The difficulty in this case was that the plaster was installed against stone walls with only a narrow space approx. 70mm deep created by the strapping between the plaster and the stone.

HPCS developed a plaster consolidation treatment program for the room that involved remotely applying acrylic-based consolidants to the back of the plaster from the face using specialized spray wand and nozzles designed for the project.

HPCS was ultimately contracted to carry out the plaster conservation work. The consolidation methodology we developed worked flawlessly and the project was a great success.
In 2019 the project received the Award of Excellence from the Canadian Association of Heritage Professionals (CAHP). The recipients included EVOQ Architecture, Ojdrovic Engineering Inc, John G. Cooke and Associates, Herb Stovel, Conservation Solutions Inc., HPCS, and Public Services and Procurement Canada.


Historic Plaster Conservation Services