The Process of Roof Repair on Historical Buildings

Alberta houses various historical sites, including buildings that date back to the 1800s. After authorities recognize a historical site, a society takes on the task of preserving the unique architecture, materials, and contents. They may update the building’s ventilation or other mechanical systems in order to maintain the site’s historical elements.

But few renovations hold as much importance as repairing, restoring, or replacing the roof. The roof protects the furnishings, interior walls, and other contents from the elements. And, because many forms of architecture influence the material and structure of a building’s roof, the roof itself may hold historical value of its own.

When a historical society notes leaks, missing roofing materials, or weathering, a roofer must follow a methodical process. Below we outline the general tasks performed during historical roofing jobs.


Some historical sites pose difficulties for renovation workers due to their age. This can make some buildings dangerous to workers of all kinds. It poses a high threat to roofers, who may need to spend long hours on top of the building. Any weakness in the structure, roof frame, or fittings could prove unsafe or even lethal.

Before beginning construction, experts inspect the building and identify any safety hazards. They may place scaffolding around the building for added support or build exterior beams to support weak portions of the roof.

Damage Location

Once roofing contractors secure the building, inspectors can begin pinpointing the damage. If the roof leaks, the location may appear more obvious. But often, the flaws lie in the framework of the roof or the roofing materials.

Contractors may work with a historian or practised craftsman to anticipate the failings of a particular era’s architecture. Understanding the behaviour of surface materials over time also helps roofers anticipate problems. Common material-based problems include the following:

  • Metal: Most historical buildings with metal roofs have lead, copper, zinc, plate, or iron sheet roofs. These primitive metals may pit, streak, or rust over time. Some may decay enough to allow pests and the elements to infiltrate.
  • Slate: Soft slate may delaminate, wear down, crack, or corrode over time. Slate shows particular vulnerability to wear caused by ice and snow.
  • Tile: Tile exhibits cracking and breakage in the long term. Older tiles may not have proper firing. In this case, the tiles change texture during thaw/freeze cycles, weakening over time.
  • Wood: Wood decays as it ages, especially if the manufacturer did not apply a finish. It may exhibit rot, wearing, or splitting.

Roofers use information about the damage’s specific location to decide how to approach era-specific architecture. They also use location to determine whether to repair the roof or replace it entirely.

Historical Research

Preserving significant roofing features represents one of the highest priorities in historical roof renovations. Roofers either work with experts to identify and retain the historically significant features, or they conduct historical research.

Roofs create much of the character on many historical buildings. For this reason, roofers undertake historical renovations with strategic planning and time period appropriate materials. In some cases, roofers may even opt for tools and fittings that builders used on the original roof.

Repair or Replacement

Once the preservation team completes a renovation plan, they begin working on the building. Roofers can handle localized damage to the roof’s surface with simple removal and replacement. They use materials like those present in the original roof to maintain the historical integrity of the site.

They may need to undertake a larger project if the damage affects the roof’s underlying structure. In this case, roofers often must remove the shingles, shakes, or sheeting and replace the structure before putting the roofing materials back onto the frame. Roofers may use modern materials and fittings to build the internal framework because they will not show to visitors or affect the character of the building.

If the damage undermines the building’s structural integrity as a whole, roofers and consultants may decide to remove the roof and frame entirely. The roofers then construct a new frame and covering that replicate the original architecture.

The next time you visit a historical building, take a look at the roof. You may notice the charm of aging materials or the hint of previous renovations. You may even see roofers working on the site during your visit. This important process ensures that people like you have the opportunity to appreciate the historical significance of the site.

If you notice architectural markers such as detailing, texturing, and features, ask the site staff about it. You may be surprised how much you can find out about a building based on its roof alone. The materials, structure, and design may indicate the time period, purpose of the building, or even the architect responsible for its construction.

For more information about roof safety, roofing materials, and residential roof maintenance, look through our other blog posts.