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Historic Roofs: Repair and Replacement Guidance for Slate, Tile, Wood, and Metal

  • Published November 7, 2026

On a historic roof, find out whether a local preservation review applies before you collect replacement bids, because an approval requirement can decide which materials you may use. National Park Service (NPS) guidance treats repair as the starting point: its 1993 brief on slate says historic slate roofs should be repaired rather than replaced whenever possible.

The NPS briefs are guidance, not law. Whether any rule binds your project depends on how your property is designated locally and on any preservation program you take part in. So the order of work is review status first, a repair assessment second, and replacement bids last.

Is Your Roof Subject to Historic Review?

Review status is a local fact, not a matter of age. A house can be individually designated, sit inside a historic district, or carry no designation at all, and your city or county can tell you which applies locally. Where review applies, a local commission or preservation office may have to approve exterior changes before the building permit is issued. A roof covering is a visible exterior feature, so treat it as in scope until the office tells you otherwise in writing.

Settle the question with four steps before any contractor walks your property:

  1. Email the city or county planning or preservation office with your address and ask whether the property is individually designated or inside a historic district.
  2. Ask whether repair, replacement in kind, or a change of material needs approval, and whether that approval must come before the building permit. Local names for the approval vary, so ask what the document is called.
  3. Ask what an application needs: photographs, product samples, drawings, a contractor’s scope.
  4. If no local office can answer, contact your State Historic Preservation Office. The National Park Service keeps a state-by-state directory of State Historic Preservation Offices.

Historic review is separate from two other approvals. A homeowners association runs its own architectural review, explained in how HOA roofing approval works, and the building department issues the permit, covered in when a roof replacement needs a permit. Each has its own process and its own paperwork, so ask each one directly.

Why Preservation Guidance Starts With Repair

NPS Preservation Brief 4, Roofing for Historic Buildings, dated February 1978, starts from a plain premise: “A weather-tight roof is basic in the preservation of a structure, regardless of its age, size, or design.”

The Secretary of the Interior’s Standards for Rehabilitation, ten standards codified at 36 CFR 67.7, put the order of work in one sentence: “Deteriorated historic features shall be repaired rather than replaced.” When a feature is too far gone to repair, the Standards say “the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials.” That gives you a three-step ladder: repair, then replace in kind, then consider a substitute.

The ladder has a practical side as well. On slate and clay tile roofs, the covering units can stay sound after the nails, flashing or underlayment around them wear out. A leak, by itself, does not show that the roofing material has failed. Replacing the whole covering to solve a fastener or flashing problem throws away material that still had service left in it, and on a designated house it can also trigger a review you could have avoided.

Slate, Clay Tile, Wood and Metal: What the Guidance Says

Each material has its own NPS guidance and its own question to put to bidders.

Material NPS guidance and date What the guidance stresses What to ask each bidder
Slate Preservation Brief 29, Spring 1993 Repair rather than replace whenever possible Which slates, fasteners and flashings can be reset or replaced one at a time
Clay tile Preservation Brief 30, Spring 1993 One of the longest life expectancies among historic roofing materials Whether broken tiles can be matched, and what condition the underlayment and flashing are in
Wood shingles Preservation Brief 19, no printed date Replacements match historic size, shape, texture and configuration How replacement shingles match thickness, exposure and coursing
Metal (terne, copper, tin) Preservation Brief 4, February 1978, plus the Standards Weather-tightness first; repair before replacement Which seams and panels can be repaired, and what metal and seam profile a replacement uses

Slate. NPS Preservation Brief 29 on historic slate roofs, written by Jeffrey S. Levine in Spring 1993, states that historic slate roofs “should be repaired rather than replaced whenever possible.” Ask each bidder to separate the condition of the slate itself from the condition of the nails and flashing, because those are different repairs with different costs. Slate grades and how to find a slater who repairs rather than replaces are covered in slate grades and qualified slaters. Slate and tile can crack under foot traffic, so leave close inspection to a contractor equipped to reach the roof without standing on it.

Clay tile. NPS Preservation Brief 30 on historic clay tile roofs, from Spring 1993, says clay tile has one of the longest life expectancies among historic roofing materials, generally about 100 years and often several hundred. Read that as what the material can do, not as the remaining life of your roof. The fasteners, flashing and underlayment beneath the tile can need work long before the tiles do, and reaching them means lifting and resetting tile, so ask how the bidder will store and protect removed tiles and how they will match any that break.

Wood shingles. NPS Preservation Brief 19 on historic wooden shingle roofs, which carries no printed date, says it is important “to match the size, shape, texture, and configuration of historic shingles.” When a wood roof does need replacement in kind, matching is the test. Treat configuration as including the exposure, the coursing pattern and any decorative butt shapes, and photograph all of them before anything comes off.

Metal. For terne-coated, copper or tinplate roofs, ask the preservation office which guidance it applies. Brief 4 addresses historic roofing in general, and the Standards’ repair-first rule applies to any historic feature. A metal roof is assembled from seamed sheets or panels, so a damaged section can be repaired or replaced without replacing the whole roof. Ask what metal and fasteners any patch uses: dissimilar metals in contact can corrode each other.

When a Substitute Material Comes Up

Preservation guidance does not rule substitutes out. Brief 4 says, “Cost and ease of maintenance may dictate the substitution of a material wholly different in appearance from the original.” Bidders raise substitutes when the original material is hard to source, when a past alteration already changed the roof, or when a bid for replacement in kind is far above the budget.

If your property is under review, expect a change of material to need approval, and build your request around the Standards’ matching test: design, color, texture and other visual qualities. Composite slate and shake products are one substitute bidders may propose; ask for the product’s ratings and installation instructions in writing. Take a physical sample and the manufacturer’s data to the preservation office before you sign anything.

A weight change matters too. If a proposed substitute is heavier than the original, or if the structure already shows sag, ask for a structural review before you commit, since the roof framing was built for the original covering.

Hazards Hidden in Old Roofs

Two hazards can change who should do the work and how. First, lead paint: if the house was built before 1978 and the job will disturb painted fascia, soffits, cornices or trim, EPA’s Renovation, Repair and Painting Program page for consumers recommends that owners of pre-1978 homes hire a contractor certified in lead-safe work practices. What that rule covers on roof jobs is explained in lead-safe rules for roof projects on pre-1978 homes.

Second, asbestos: EPA’s Learn About Asbestos page lists roofing and siding shingles among building products that can contain asbestos, and exposure becomes a concern when the material is disturbed or damaged. If an older roofing layer or siding cannot be identified, ask for testing before tear-off, not after the crew has started; testing and removal rules for asbestos roofing explains how testing works and why disturbing it yourself is risky.

What to Document Before Anyone Bids

A record made before work starts does two jobs. It supports any review application, and it lets you check that the finished roof matches what was there. Build it from the ground, upper windows and the attic:

  • Photograph every slope from the ground and from upper windows, using a zoom lens or binoculars for detail. Capture ridges, hips, valleys, dormers, chimneys, gutters and the cornice.
  • Record the material, color, approximate exposure, coursing pattern, any decorative shapes or bands, the ridge and hip treatment, and the flashing and gutter metal where you can see it.
  • After a rain, check the attic with a flashlight and note where water shows on the underside of the deck, then match those spots to interior stains.
  • Gather old permits, prior approvals, historic photographs and invoices for earlier repairs.
  • Ask each bidder for a written assessment listing what can be repaired, what needs replacement in kind, and the reason for each, plus how they will reach the roof without damaging it.

Compare bids on the assessment before the price. A bid that proposes full replacement without explaining why repair will not work has skipped the first question the guidance asks. Ask each bidder to name comparable historic roofs they have repaired, and look at one if you can.

Repair, Replace in Kind, or Ask for Approval First?

If the property is designated or inside a historic district, get the approval decision in writing before you sign a contract, and make the contract conditional on that approval. Signing first and applying second can put you on the hook for a scope that may not be allowed.

If the written assessments say the roof can be repaired, repair it; that is where the NPS guidance and the Standards both begin. If repair is not workable, replace in kind and hold the contractor to the details you documented. If a substitute is on the table, take a sample and its data to the preservation office first. If the property has no designation, ordinary permit rules apply, and the repair-first logic still protects original material you cannot buy again.

Start with one email to the city or county planning office asking whether your address is designated. The decisions that follow once you have that answer are laid out in the roofing guide’s decision paths.

This guide is general information for U.S. homeowners, not legal, insurance, tax, or engineering advice. Codes, laws, and policy terms vary by location and change over time; confirm details with your local building department, your insurer, or a licensed professional.

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