Restoring Notre Dame to its original glory will be a challenging and long drawn out process, necessitating inputs from a global army of historians, experts, architects, engineers, builders and craftspeople.

Following the devastating fire that destroyed the timber-beamed roof of the 850-year-old cathedral, the inside of the structure is currently exposed to the elements. Despite the intensity of the inferno, most of the structure is still intact including the two rectangular towers and the massive vaulted ceiling.

The restoration process will be assisted by records available on the cathedral. Over the years, Notre Dame has been thoroughly documented by historians and archaeologists through exhaustive plans, images, and detailed 3D laser scans of the interior.

Major challenges facing the restorers include securing the cathedral without disturbing the debris, which may provide valuable information, in addition to salvaging the material for reuse during restoration. Detailed checks will have to be carried out to ascertain the stability of the vaulted ceiling, which was exposed to high heat. The cathedral's stained-glass rose windows were also exposed to extreme heat followed by cold water, which may have subjected them to ‘thermal shock’.

Restoration work is expected to begin once the building is stabilised and the damage assessed. While rebuilding Notre Dame will be an international effort, a decision will have to be made about preserving the cathedral and restoring it to its former state or alternatively, create a more contemporary version of the cathedral more suited to this century.

Sourcing materials to match the existing structure will be another challenge – the burnt-out cathedral roof featured oak beams cut from centuries-old trees. Restoration in the 21st century also means the building will need to adhere to the health and safety standards applicable to builds.

According to global experts, the restoration of Notre Dame may take decades and will be an expensive process. A global appeal for funds has elicited instant response with millions of dollars already pledged by individuals and organisations worldwide.

The restoration is also an opportunity for various stakeholders to better understand medieval history and practices of the past.