Historic Roof Replacement and Repair

When you live or work in a historic building, you have a duty to preserve its legacy for future generations. If the roof starts to fail, the underlying masonry, plaster and wood will also start to suffer, so it’s imperative to get it fixed quickly. 

However, taking care of a historic roof isn’t the same thing as taking care of a modern roof. The materials are different, the paperwork is more complicated, and you need support from someone who understands historical craftsmanship.

In this article, you’ll discover why repairing a historic roof is often preferable to replacing it altogether. You’ll also learn about some common challenges encountered when repairing a historic roof and how to address them.

Repair over replacement

If your historical roof has a problem, your first step should be to call a professional to see if the roof can be repaired.

As a general rule, repair is preferable to replacement, for a number of reasons:

• Much of your roof’s unique character is due to the original roofing materials and old-school construction methods. Repairing the roof will preserve its historical charm. 
• Often, you’ll need to maintain the original materials in order to remain compliant with local, state or federal preservation standards.
• Historic roofs were usually built from durable, high-quality materials that outperform modern alternatives. Repairing preserves these materials instead of discarding them.
• Full replacement is often more expensive, especially when specialized or custom materials are required.

To repair your historical roof, your roofer will fix sections that have deteriorated over time, using materials that match the originals. For example, individual slates, tiles or shingles that have come loose can often be reattached, restoring performance without altering appearance.

A common problem on historical roofs is when small metal components like flashing and paneling start to fail. Your roofer can replace broken flashing with historically appropriate metal to prevent leaks, patch small holes that have opened due to corrosion, and re-solder any seams that have been damaged. 

In cases where the problem with your historical roof originated beneath the surface, your roofer will examine the decking, mortar joints and parapets. They’ll then make any repairs necessary to stabilize the roof system as a whole. 

Sometimes, a full replacement is unavoidable. This is the case when:

• A large proportion of the roof is cracked, corroded or missing
• Rot has caused the entire roof structure to deteriorate and sag
• Historical roofing materials have already been repaired multiple times
• The are numerous leaks that resist all attempts to repair them
• The roof no longer meets safety requirements in local building codes
• The roof was severely damaged by a storm or a fire

If you have to replace the roof, it’s generally advisable to replace it “in kind.” This means that you try to match the original materials, appearance and installation methods as closely as possible to retain the building’s historical character. 

Challenges with historical roofs 

Whether you repair or replace your historical roof, doing so will come with some unique challenges that aren’t present in more modern properties. Here are some of the most common ones. 

Area Where There’s a Challenge	Description
Materials	Sourcing old-school materials like slate, copper, clay, and wood.
Structure	Older buildings can’t bear the same structural load that modern ones can.
Paperwork	Expect extra building codes and preservation boards for older roofs.
Cost	Specialized labor and premium materials cost more than a regular roof job.
Labor	Be picky about finding a roofer with the right experience in historical roofs.

Let’s explore these in more detail.

Sourcing authentic materials 

The most commonly used material on modern roofs is asphalt shingles. However, historical roofs were often made from:

• Slate: initially imported from England and Wales, and later quarried on American soil in states like Vermont and Pennsylvania
• Copper: used because it doesn’t rust due to a protective layer called a patina
• Clay: particularly popular in large cities like Boston or New York due to its resistance to fire
• Wood: pine in New England, more likely to be oak in the South

These materials form such a part of a historical roof’s character that it’s wise to match the original materials as closely as possible. 

But sourcing authentic materials is far from easy. It’s possible that they’re no longer manufactured at all! If you try to reclaim older materials from other buildings, there’s no guarantee that you’ll have sufficient quantity to fix your roof, or that the materials are still in good enough condition to be usable. Old-school materials that are still used today, such as slate and copper, can also be very expensive. 

If it’s not possible to find the exact materials you need, get as close as you can in terms of color, size, thickness and texture. For example, there are some asphalt shingles that are engineered to look like wood. You could likewise consider replacing copper roofing with copper-coated steel. Local building codes generally allow for these kinds of improvised solutions, but it’s worth checking with your roofer to be sure. 

Structural limitations of older buildings

Older buildings were not constructed to bear the weight of modern roofing materials, thick underlayments, or gadgetry such as satellite dishes. 

Many historic buildings, particularly those dating from the 19th century or earlier, have small rafters and joists, or long spans with few supports. Older timbers were often cut by hand, making them irregular and less good at bearing weight. Joinery was pegged together haphazardly with wood, rather than with metal fasteners. 

Over time, it’s likely that historical roof frames have become weakened and brittle. They might suffer from:

• Hidden rot or insect damage
• Fatigue at joints
• Sagging of the rafters and roof decking

All these factors limit how much weight a historical roof can bear, as well as how much disturbance the structure can tolerate during the repair process. 

To prevent your roof from collapsing during repair work, it’s advisable to bring in a structural engineer at the beginning of the project who’s familiar with historical buildings. They’ll be able to analyze the existing framing to see how much load it can bear, as well as check for any elements of the structure that might be prone to moving.

Once you know how much weight the structure can hold, your plan for repairing it should make sure that the replacement materials closely match the weight of the original roof. 

As the project progresses, a good roofer should be careful to disassemble only one part of the roof at a time. Larger tear-offs can destabilize masonry walls, loosen joints in timber framing, or cause the roof structure to move in unintended ways. Targeted repairs reduce these risks. 

Complex paperwork

Before a historical roof can be repaired, the building owner needs to conduct research into all the extra compliance requirements that apply to historical buildings. For example, there might be:

• Preservation society boards
• Guidelines for historic districts
• Building codes specific to older structures

Your property could be subjected to any or all of these at the local, state and/or federal level. That’s a lot of paperwork to sift through! 

More often than not, renovations on historical homes require the homeowner to seek permission from a local board. It’s important to start this process early, as bureaucracy can be time-consuming. This is especially true if you need to get approval from multiple boards, as each will have its own timeline. 

The board will expect you to integrate any updates they’ve made to local building codes, without changing your roof’s appearance. This can add significant design constraints to your project. It’s critical to be aware of these constraints before you spend time and money making repairs that are non-compliant. Failure to comply can result in fines or legal action. 

Higher costs 

It’s more expensive to repair or replace a historical roof than a modern one. It’s fairly self-evident that you’re paying for:

• Premium materials like slate and copper, or even custom-designed materials that match the original roof and may have to be imported.
• Specialized labor involving a team of experts who understand historical roof architecture.

What might be less obvious is that repairing old roofs is prone to scope creep. 

Let’s say that you hire a team of roofers and source some old-school materials to fix your aging roof. The structural engineer assesses the damage and gives you a scope of work. Based on that scope, you get your roofer to give you a quote. 

As the project progresses, the roofer has to open up parts of the roof to do his job. Since it’s an older roof, he uncovers rot, moisture and corrosion that weren’t obvious to the engineer at the start of the process, because they were concealed from view. 

These issues end up pushing up the price of your roof renovation project. And just when you think you’ve found all the structural issues, you find another one!

It’s smart to plan for contingencies in your budget to make sure you can adapt to situations like this. 

Understanding traditional craftsmanship

Historic roofs are built using techniques that require specialized knowledge. So building owners can’t simply hire a generalist roofer and start tearing off shingles.

Using a contractor who lacks experience with historic roofs carries real risks. Improper installation can result in moisture infiltration, warped or sagging decking, and permanent damage to original materials. Modern shortcuts like synthetic underlayments or aggressive fastening may seem convenient, but they can compromise the roof’s longevity and violate preservation standards.

Finding the right specialist can be challenging. Consider interviewing a few different roofers and asking them questions such as:

• Have you worked on roofs from this period or made from this material?
• Can you show examples of previous historic roof projects?
• Are you familiar with local preservation guidelines?
• What traditional techniques will you use instead of modern alternatives?

Next steps

Not all contractors have the required experience to repair or replace a historical roof. But here at Presidio, we do! 

Give us a call on (210) 670-6890 today, and we’ll come over to assess your roof free of charge.