Flat Roof Repair in Lexington KY: Which Code Applies

Code Notes · Low-Slope & Commercial

Flat roof repair in Lexington KY runs into a question most building owners never think to ask: which rulebook is the inspector actually holding? Kentucky does not let a city write its own building code, and the answer is not the residential code most roofing articles quote. It is a different regulation, pointing at a different code book, with its own fee arithmetic for repairs — and the arithmetic has a floor that surprises people.

Which building code applies to a commercial flat roof in Kentucky?

The 2015 International Building Code, as adopted by 815 KAR 7:120, with the Kentucky amendments in the 2018 Kentucky Building Code overriding anything that conflicts.

Section 2 of the regulation is unusually plain about it. The 2015 International Building Code is the mandatory state building code for all buildings constructed in Kentucky, with three carve-outs: the Kentucky amendments in the 2018 Kentucky Building Code supersede any conflicting provision in the 2015 IBC; one-family dwellings, two-family dwellings and townhouses are instead governed by 815 KAR 7:125; and manufactured homes are governed by KRS 227.550 through 227.665.

Read the second carve-out again, because it is the one that sorts roofs. If the flat roof is on a house, a duplex or a townhouse, you are in the residential regulation. If it is on anything else — a shop, a strip centre, a warehouse, an apartment building of three or more units, a church, a clinic — you are in the building code, and the roofing chapter that governs your repair is not the one in the residential code book. A contractor quoting residential-code section numbers at you on a commercial low-slope roof is quoting the wrong book.

Section 5 of the regulation incorporates both documents by reference by name and edition: the “2015 International Building Code” and the “2018 Kentucky Building Code,” Fourth Edition, February 2024. That February 2024 Fourth Edition date is worth noting if you are working from a PDF someone emailed you a few years ago — the amendment document has been revised, and the current version of the regulation carries an effective date of December 3, 2024.

Can Lexington have its own roofing code?

No. The statutory authority behind the regulation requires a mandatory uniform state building code covering the construction of all buildings in Kentucky.

The regulation’s own “necessity, function, and conformity” statement says that KRS 198B.040(7) and KRS 198B.050 require the department to promulgate a mandatory uniform state building code establishing standards for the construction of all buildings in the state. The word doing the work there is uniform. The technical roofing requirements on a low-slope roof in Lexington are the same ones that apply in Richmond, Frankfort or Paducah.

What does change locally is administration — who issues the permit, who inspects it, how fast, and what the local fee is. That is a genuinely different thing from the technical standard, and conflating the two is how building owners end up believing a repair that is fine in one county is prohibited in the next.

What does state plan review cost on a flat roof repair?

Where the department reviews plans for an alteration or repair, the fee is the lower of two formulas — and it cannot fall below a $285 minimum.

Section 3(6) of 815 KAR 7:120 sets it out. For alterations and repairs not otherwise covered by the fee schedule, the plan review fee is calculated using the lower result of either multiplying the cost of the alterations or repairs by 0.0030, or multiplying the total area being altered or repaired by the cost per square foot for the occupancy type. The square footage is taken from the outside dimensions of the area being altered or repaired, and the minimum fee under that subsection is $285.

The per-square-foot multipliers come from Table 121.3.1 in the same regulation:

Occupancy type	Cost per square foot
Assembly	16 cents
Business	15 cents
Day care centers	15 cents
Educational	15 cents
High Hazard	16 cents
Industrial factories	15 cents
Institutional	16 cents
Mercantile	15 cents
Residential	15 cents
Storage	15 cents
Utility and Miscellaneous	13 cents
Production greenhouse	10 cents

Working the arithmetic out loud

Because the rule takes the lower of the two results and then applies a $285 floor, the fee only rises above $285 when both formulas clear $285. That makes the break-even points calculable directly from the regulation’s own numbers:

• Cost formula: $285 ÷ 0.0030 = $95,000 of repair cost
• Area formula at 15 cents (Business, Mercantile, Industrial, Storage, Residential): $285 ÷ $0.15 = 1,900 square feet
• Area formula at 16 cents (Assembly, High Hazard, Institutional): $285 ÷ $0.16 = 1,781 square feet
• Area formula at 13 cents (Utility and Miscellaneous): $285 ÷ $0.13 = 2,192 square feet

So for a business-occupancy flat roof, a department plan review of an alteration or repair sits at the $285 minimum unless the job both costs more than $95,000 and covers more than 1,900 square feet of roof. Miss either threshold and the lower formula pulls you back to the floor. That is arithmetic from the published multipliers, not an estimate — run it yourself and you will get the same figures.

Two cautions, and they matter more than the math. First, this is the Department of Housing, Buildings and Construction’s own plan review and inspection fee schedule — it is not a local permit fee, and a city or county building department sets its own. Second, and more important: nothing above decides whether your particular repair requires plan review at all. That determination belongs to the authority having jurisdiction over your building, and it is the first call to make, before anyone prices anything.

What to do with this before you accept a quote

Ask three questions in this order and most flat-roof confusion resolves itself. Which code book governs this building — the building code or the residential code? Has anyone confirmed with the local building department whether this scope triggers plan review? And is the review fee shown in the quote as a pass-through line item, or buried? A contractor who answers all three without hedging is a contractor who has done this on a commercial roof before. One who treats the question as a nuisance is telling you something too.

If you are still working out what your roof is in code terms, start with what the Kentucky code calls your flat roof. For the repair work itself, see commercial flat roof repair and our roof repair in Lexington, KY page.

Primary sources, verified October 30, 2026: the regulation is 815 KAR 7:120, Kentucky Building Code, published by the Kentucky Legislative Research Commission. The incorporated code documents are held by the Kentucky Department of Housing, Buildings and Construction, which the regulation lists at 500 Mero Street, Frankfort, Kentucky 40601, Monday through Friday, 8:00 a.m. to 4:30 p.m.

Does my flat roof repair definitely need a permit?

That is not answerable from the fee regulation, and anyone who answers it for you sight-unseen is guessing. The fee schedule tells you what plan review costs if it is required; whether your scope requires it is a determination for the authority having jurisdiction over the building. Call them first.

My building is a four-unit apartment with a flat roof. Which code?

The regulation routes one-family dwellings, two-family dwellings and townhouses to 815 KAR 7:125. A building with more units than that is not in that carve-out, which puts it under the building code adopted by 815 KAR 7:120. Confirm the occupancy classification with your building department rather than assuming it from unit count alone.

Is the $285 minimum per roof or per building?

The regulation states it as the minimum fee for review of plans pursuant to that subsection, with the area measured by the outside dimensions of the area being altered or repaired. How that applies to a specific scope — one roof, phased work, multiple buildings on a site — is a question for the reviewing department, not something to infer from the text.

This page is general education about a published Kentucky regulation. It is not a code ruling, not legal advice, and not a quote for any specific roof.

Last updated: October 30, 2026

By Central Roof Repair · Call or text (859) 310-1209.

Disclosure: Central Roof Repair is owned by Marcos Gil.