Ottawa Parliament Hill Upgrade: Underground Welcome Centre, Base Isolation and a Century-Long Restoration

The B1M reports on Ottawa’s Parliament Hill transformation, a $5 billion, multi-year project to renovate the Centre Block, add an underground Welcome Centre, and reinforce the building for seismic events. Beginning with a deep bedrock excavation in 2020, the work aims to preserve Gothic Revival architecture while modernising facilities and ensuring long-term stability. MPs and Senators have relocated to other buildings as restoration progresses, with a target completion around 2031 and a staged reopening thereafter. The end result will be a restored, secure, and accessible Parliament complex prepared for the next century of service.

Introduction and historical context

The Canadian Parliament on Parliament Hill in Ottawa sits in a Gothic Revival complex of three blocks arranged around a central lawn. The centre block houses the House of Commons and the Senate chambers, with the Peace Tower serving as a national symbol and a memorial for World War I casualties. Construction began in 1859, with a devastating fire in 1916 that left only the Library intact. A new centre block arose, finished in 1927, and the Peace Tower was added, 70% taller than its predecessor and housing 53 bells, drawing comparisons to London’s Big Ben.

The impetus for the renovation

Over the last century the building has deteriorated, facing eroded concrete supports, water infiltration, rusting steel, and a lack of earthquake protection. With millions of visitors every year, the site also faced overcrowding and security gaps. Public Services and Procurement Canada launched the largest and most complex restoration program in the country to fully renovate and structurally reinforce the centre block while preserving its heritage significance.

The scale and milestones of the project

Key milestones include a dramatic 23 metre deep pit excavated across the front of the building, created by blasting and removing roughly 40,000 truckloads of rock. The work began in 2020 and continued through 2023, paving the way for a massive underground Welcome Centre that will connect to the existing blocks. By 2025 concrete foundations and essential internal structures began to take shape, while the most intricate engineering challenges lay ahead, particularly the integration of base isolation to protect against earthquakes and to detach the building from ground motion.

Engineering feats and safety measures

The core of the upgrade is the base isolation system, featuring more than 500 isolators positioned between the current foundation and the new underground structure. An extensive program of piling—around 800 piles—will create a robust foundation grid of steel and reinforced concrete. Temporary support posts will hold the centre block during excavation, after which the new basement levels will rise from the bottom up. On top of that, a network of vibration monitors—about 500 sensors—will track movement and ensure the rehabilitation does not cause more damage than it fixes.

Heritage preservation and interior restoration

Inside the centre block, the work is equally meticulous, stripping the building to its structural elements and restoring more than 20,000 heritage assets. About 50 rooms are being refurbished, including hundreds of stained glass windows, sculptures, and other decorative arts. Exterior restoration involves cleaning some 365,000 stones using lasers that vaporise surface deposits without harming the stone. The project also aims to preserve and display the Peace Tower’s legacy within a newly designed space that brings in natural light through skylights.

Relocation, access, and project timeline

While construction continues, MPs and senators have relocated to the West Block and the Senate of Canada building. The project is planned to run through 2031, with the centre block set to reopen in stages and a full reopening anticipated roughly a year after the main renovations are completed. When finished, Parliament will gain a secure, accessible front door via a raised external pathway, a main hall that integrates the Peace Tower’s presence, and expanded connections to the West and East blocks, all designed to serve Canada for another century.

What this means for the future of Parliament

Ottawa’s restoration goes beyond cosmetic patchwork. It is an ambitious attempt to safeguard a national icon against earthquakes, to provide a modern, secure visitor experience, and to restore irreplaceable artworks and architectural details. The outcome will be a fully restored and modernised Parliament that can withstand future challenges while continuing to symbolize Canada’s democratic values.