What the Rule Actually Says
The 25% Rule comes from Section R908.3.1 of the 2018 International Residential Code, which has been adopted by most DFW jurisdictions. The exact text reads:
“Not more than 25 percent of the roof covering of any building or structure shall be removed and replaced in any 12-month period unless the entire roof covering is replaced and is made to conform to the requirements of this code.”
In plain English: once 25% of a roof section is being replaced, the whole section has to come off and be brought up to current code. You cannot patch your way around it. Once you cross the threshold, partial work is no longer compliant.
Why the Rule Exists
The reasoning behind the rule is simple. When you patch over a deteriorated underlayment with new shingles, you create a roof system with mismatched layers. The new shingles tie into older underlayment, older flashing, and older decking. Within 2-5 years, leaks usually develop at the seams where new meets old. The 25% threshold is the building code’s way of saying that once you cross a meaningful share of the slope, the whole slope must be reset to a single performance baseline. It also forces older roofs onto current code — better ice-and-water shield placement, drip edge metal, ventilation, and decking nailing patterns — instead of grandfathering decades-old construction practices.
A Real DFW Example
A 2,400 sqft Frisco home gets hit by a 1.5″ hailstorm. The carrier’s adjuster inspects, scopes 14 squares (1,400 sqft) of replacement across the front and rear slopes, and writes the loss at $7,800.
Our crew measures the actual roof:
| Slope | Total Area | Adjuster Scoped Damage | % of Slope | Code Requirement |
|---|---|---|---|---|
| Front (street-facing) | 1,000 sqft | 340 sqft | 34% | FULL SLOPE |
| Rear | 1,000 sqft | 280 sqft | 28% | FULL SLOPE |
| Left side | 200 sqft | 30 sqft | 15% | Patch only |
| Right side | 200 sqft | 25 sqft | 12.5% | Patch only |
Both major slopes cross the 25% threshold. The adjuster’s partial-repair scope of 14 squares is non-compliant. Filing the supplement under code requirements bumps the settlement from $7,800 to roughly $13,200(full front + rear slopes, plus the small patches on the left and right sides). All of that additional payment is owed under the Law and Ordinance coverage in the homeowner’s RCV policy.
How Insurance Carriers Handle the Rule
Adjusters know the rule. Most apply it correctly when the slope-level math is obvious. Where supplements typically arise:
- The first scope was eyeballed, not measured. Adjusters working high volume after a major hailstorm sometimes scope from photos or quick estimates. The actual slope-by-slope math comes out higher.
- Damage is concentrated. A slope with 25 hail strikes clustered in one quadrant looks small in photos but exceeds 25% when you mark every strike on the diagram.
- Old shingles cannot be matched. Even if damage is below 25%, if the shingle line has been discontinued (especially older 3-tab patterns), you have a separate code argument that partial repair will not deliver a uniform finished surface — and most carriers will agree to a slope replacement on aesthetic-uniformity grounds.
- Decking damage discovered during tear-off. A 25%-threshold slope may also reveal rotted decking that requires sheathing replacement — which adds line items the adjuster did not initially scope.
Law and Ordinance Coverage: How You Get Paid Under the Rule
Most Texas RCV homeowner policies include Law and Ordinance coverage(sometimes called “Ordinance or Law”). It pays the additional cost of bringing a damaged building up to current code, even when that cost exceeds the actual cash value of what was damaged. There are typically two layers:
- Coverage A — Building Loss: Pays for the undamaged portion of the structure that has to be torn out and rebuilt because of code. This is what triggers under the 25% Rule when the carrier replaces an entire slope to comply.
- Coverage B — Increased Cost of Construction: Pays for code-required upgrades themselves — drip edge that was not previously required, ice-and-water shield in valleys, modern decking attachment patterns, current ventilation standards.
These coverages are typically capped at 10-25% of the dwelling limit. On a $300,000 dwelling, that is $30,000-$75,000 of code coverage available to apply against your roof claim. Most homeowners never know they have it. Most adjusters never bring it up unless the contractor pushes the supplement.
When the Rule Does NOT Apply
The 25% Rule is not a magic wand for full replacement. It only triggers when:
- The damage to a single slope crosses 25% of that slope’s area
- The repair work itself, separately, would replace 25% of any slope in a 12-month window
- Your jurisdiction has adopted the 2015, 2018, or 2021 IRC (most DFW cities have)
If the damage is concentrated entirely on a single small section of one slope and never approaches 25%, the carrier is allowed to scope only the patch. There is no code violation in repairing 8% of a slope. In those cases, your settlement reflects the partial scope, period.
Watch out for any contractor who tells you the 25% Rule means “the insurance has to give you a new roof no matter what.” That is a common storm-chaser pitch and it is wrong. The rule is real, but it is a code interpretation, not a guaranteed payout multiplier.
What This Looks Like in Other DFW Cities
Code adoption varies. We pull permits in 30+ DFW jurisdictions every year. As of 2026:
| Jurisdiction | Adopted IRC | 25% Rule Active |
|---|---|---|
| Dallas | 2018 IRC w/ amendments | Yes |
| Fort Worth | 2018 IRC | Yes |
| Plano | 2018 IRC | Yes |
| Frisco | 2018 IRC | Yes |
| Flower Mound | 2018 IRC | Yes |
| Highland Village | 2018 IRC | Yes |
| Lewisville | 2018 IRC | Yes |
| Denton | 2018 IRC | Yes |
| Allen / McKinney / Prosper | 2018 IRC | Yes |
Code adoption updates periodically. Always verify with your specific city’s building department or your contractor at permit time.
How JRH Applies the Rule on Every Insurance Claim
- Per-slope measurements with calibrated drone photogrammetry — no eyeballing
- Damage marked strike-by-strike on every slope, percentages calculated
- Adjuster meeting with the math in writing, not a verbal challenge
- Supplement filed within 7 days of any short-scoped roof claim
- Permit pulled in every DFW jurisdiction we work in — never “under the table”
- Final invoice and code-compliance documentation submitted to your carrier so recoverable depreciation pays out
If your adjuster has scoped a partial repair and you want a second opinion on whether your slopes cross the 25% threshold, we will inspect for free and put the percentages in writing. Start with a 60-second roof check or schedule the on-site inspection.
FAQ
What is the Texas 25% Rule for roof replacement?
The Texas 25% Rule is a building code provision adopted from the 2018 International Residential Code that requires a full roof replacement once 25% or more of a single roof slope (or section) has been replaced or repaired within any 12-month period. It is enforced through municipal building inspectors during the permit and final inspection process.
Is the 25% Rule a state law or a city ordinance?
It is a building code, not a state law. Most DFW cities — Dallas, Fort Worth, Plano, Frisco, Flower Mound, Highland Village, Lewisville, Allen, McKinney, Denton, Arlington, Mesquite, Garland, Irving — have adopted some version of the 2015, 2018, or 2021 IRC, all of which carry the 25% provision. Always verify with the specific city issuing your permit.
Does my insurance company have to pay for full replacement under the 25% Rule?
If the adjuster initially scoped a partial repair but inspection of the slope reveals damage at or above the 25% threshold, the carrier typically must approve full slope replacement to comply with code. This is one of the most common supplement situations we file. Code-required replacements are reimbursable under the Law and Ordinance coverage in most Texas RCV policies.
How is the 25% calculated — is it 25% of the whole roof or 25% of one slope?
In most DFW jurisdictions enforcing the 2018 IRC, the 25% threshold applies to a single roof section or slope, not the entire roof. A 1,000 sqft slope with 250 sqft of damage triggers full slope replacement. The full roof does not have to be replaced unless multiple slopes individually cross the threshold or your municipality interprets the code more broadly.
Does the 25% Rule apply to commercial flat roofs in Texas?
A similar provision exists in the 2018 International Building Code for commercial properties, but the threshold is sometimes counted differently — by area replaced over the life of the roof rather than within a 12-month window. Commercial flat roof code interpretation varies significantly by jurisdiction. Always pull a permit and let the inspector apply the code locally.
Will my contractor know if my slope crosses the 25% threshold?
Yes — measuring damage area against slope area is part of every JRH inspection. We measure each slope, count damaged shingles or torn membrane area, and document the percentage. If we find a slope at 28% damage that the adjuster scoped at 12 squares of patching, we file a supplement to convert it to a full slope replacement.
Can I waive the 25% Rule if I just want a cheap repair?
No. Building codes are not optional and are enforced through the permit process. A roofer offering to "just patch it" without pulling a permit is exposing you to permit-without-final-inspection liability that surfaces when you sell the home. JRH pulls permits on every job.
Get a 60-Second Roof Estimate
We will measure each slope, mark the damage percentages, and tell you whether the 25% Rule applies before you accept the carrier’s first check.