What Is the 25% Rule for Roofing? It Depends on Where You Are

The 25% rule for roofing is a rule of thumb that comes from some local building codes. In general terms, it says that if more than about 25% of a roof is repaired or replaced within a set period, often 12 months, the whole roof may need to be brought up to current code.

The most important thing to know is that it is not a universal rule. It is not a national law, and many jurisdictions do not have it. Where it exists, its exact wording, its time window and its exceptions depend on the code edition and any local amendments. Some places have changed or removed it over time.

This article is general information, not legal advice. Always confirm with your local building department before you rely on it.

People often mix up two separate things. A 25% rule, where it applies, is a building code matter. The local building department enforces it. Insurance coverage is a different question, decided by the policy and the carrier.

That difference explains a common source of confusion. A code may require more work than an insurance estimate originally included. Whether the insurer pays for that extra work depends on the policy, for example whether it includes coverage often called Ordinance or Law, which can address the added cost of meeting code. Policies differ, so read the actual policy.

The comparison below separates the two.

Several things make the rule different from place to place:

Because of that, two roofers in two nearby towns can honestly give different answers. The right source is always the local building department for the address in question.

If a job might involve a repair threshold, the safest approach is a short, repeatable routine rather than relying on memory or a forum post.

When you bring it to an adjuster, cite the actual source: the code section and the building department's confirmation, if you have it. A specific reference is far more useful than saying a rule exists. This is the same discipline that applies to any code-based item on a supplement. For related items, see code upgrades and Ordinance and Law coverage.

These come up often and are worth avoiding:

If you are unsure, say so, and send the question to the building department.

If code-required work is involved, treat it like any other supplement item: show the condition, the requirement and the proof.

The free supplement checklist and the supplement template help keep that package organized. No documentation can guarantee a result, because coverage depends on the claim, the policy and the carrier.

Supplement Snap helps crews capture photos, areas and notes on the roof and turn them into an organized report. If a local code requirement affects the job, the report is where you attach the measurements and the proof. The tool does not decide whether a rule applies. That still comes from your local authority and the carrier.

These examples are fictional and simplified. They show why the same repair can lead to different outcomes depending on the local rules. Do not treat them as advice for any real property.

Scenario one: A jurisdiction has adopted a repair threshold. A storm damages part of one slope, and the repair covers a small portion of the roof. The work stays under the threshold, so the rest of the roof is not affected by that rule.

Scenario two: The same jurisdiction, but damage spans several slopes. The repair area adds up to more than the threshold within the stated period. The building department may require the roof covering to meet current code for the whole roof.

Scenario three: A different jurisdiction has no repair threshold at all. The same repairs are permitted without the code requirement in scenario two.

The lesson is not to memorize a number. It is to ask which rule applies at the address, and to document the repair area carefully so the answer can be applied accurately.

A short call or email to the local building department can settle most uncertainty. Useful questions:

Record the name, date and answer. If code-required work becomes part of a supplement, that record is exactly what an adjuster needs to evaluate it.