Central Roof Repair · Kentucky code
A roof re-cover — new covering installed over the old one, no tear-off — is permitted in Kentucky in four situations and forbidden in three. The three that forbid it are short, specific and easy to check from the ground: a water-soaked or deteriorated existing roof, a slate or tile covering, or a roof that already carries two or more applications of any type. Section R908 of the residential code Kentucky has adopted says so in about a hundred words.
Last updated: October 11, 2026
When is a roof re-cover not allowed in Kentucky?
Three conditions, any one of which forces a tear-off: a water-soaked or deteriorated base, slate or tile, or a roof already carrying two or more layers.
Section R908.3.1.1 is titled “Roof Re-cover Not Allowed,” and it lists them without qualification. A re-cover is not permitted “where the existing roof or roof covering is water soaked or has deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing”; “where the existing roof covering is slate, clay, cement or asbestos-cement tile”; or “where the existing roof has two or more applications of any type of roof covering.”
Read the third one carefully, because it is the one that catches most Central Kentucky houses. It says two or more applications of any type — not two layers of shingles. A shingle roof laid over an original roll-roofing or shake layer is already at two, and the next covering has to come off everything. The count is of applications, not of the material you can see.
“Two or more applications of any type of roof covering.” Not two layers of shingles — two of anything. That single word decides whether your next roof is a re-cover or a tear-off.
When does the code permit a re-cover?
Four situations, in R908.3.1 — manufacturer-approved installation, a self-supporting system such as standing-seam metal, specific coverings over wood shake, and a coating over spray foam.
Section R908.3.1 permits installing a new roof covering over an existing one where any of the following occur: where the new covering “is installed in accordance with the roof covering manufacturer’s approved instructions”; where “complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building’s structural system and do not rely on existing roofs and roof coverings for support” are used, which “shall not require the removal of existing roof coverings”; where “metal panel, metal shingle and concrete and clay tile roof coverings” are installed over existing wood shake roofs in accordance with Section R908.4; and where “a new protective coating over an existing spray polyurethane foam roofing system” is applied, which is “permitted without tear-off of existing roof coverings.”
The wood-shake route carries a condition that is easy to miss. R908.4 says that where the new covering over wood shingle or shake “creates a combustible concealed space, the entire existing surface shall be covered with gypsum board, mineral fiber, glass fiber or other approved materials securely fastened in place.” That is a fire-separation requirement wearing a reroofing label, and it is a real line item, not a detail.
Does a reroof have to meet the minimum slope for the new covering?
Not the quarter-inch-in-twelve drainage minimum, if the existing roof provides positive drainage. R908.1 carries that exception explicitly.
This is the most useful sentence in the whole section for a low-slope repair, and almost nobody quotes it. R908.1 requires reroofing materials and methods to comply with Chapter 9, then excepts two things. First: “Reroofing shall not be required to meet the minimum design slope requirement of one-quarter unit vertical in 12 units horizontal (2-percent slope) in Section R905 for roofs that provide positive roof drainage.” Second: “For roofs that provide positive drainage, re-covering or replacing an existing roof covering shall not require the secondary (emergency overflow) drains or scuppers of Section R903.4.1 to be added to an existing roof.”
In other words, an existing low-slope roof that actually drains does not have to be rebuilt to reach the design slope that a new roof of the same type would need. The minimums discussed in our notes on what the Kentucky code calls a flat roof versus a low-slope roof and on mineral-surfaced roll roofing’s slope floor are design-slope requirements in Section R905. R908.1 is the reroofing door out of the first of them where drainage is already working — and “provides positive roof drainage” is the condition that has to be true, which is a question about the existing roof, not about the product going on it.
What does a roof replacement actually include?
Removal of every existing layer down to the deck — with one exception for an adhered ice barrier membrane, which may stay and be covered.
R908.3: “Roof replacement shall include the removal of existing layers of roof coverings down to the roof deck.” The exception: “Where the existing roof assembly includes an ice barrier membrane that is adhered to the roof deck, the existing ice barrier membrane shall be permitted to remain in place and covered with an additional layer of ice barrier membrane in accordance with Section R905.” That matters here because Kentucky requires an ice barrier in the first place on eaves — see where the code requires an ice barrier on a Kentucky roof.
R908.2 sits underneath both paths: “the structural roof components shall be capable of supporting the roof covering system and the material and equipment loads that will be encountered during installation of the roof covering system.” That is a loads check for the install itself, not just the finished assembly — the reason a stack of bundles does not get staged in one spot on an old deck.
What can and cannot be reinstalled?
Sound slate, clay or cement tile may go back on. Damaged tile, rusted flashings and aggregate surfacing may not.
R908.5: “Existing slate, clay or cement tile shall be permitted for reinstallation, except that damaged, cracked or broken slate or tile shall not be reinstalled. Any existing flashings, edgings, outlets, vents or similar devices that are a part of the assembly shall be replaced where rusted, damaged or deteriorated. Aggregate surfacing materials shall not be reinstalled.” R908.6 adds that flashings “shall be reconstructed in accordance with approved manufacturer’s installation instructions,” and that “metal flashing to which bituminous materials are to be adhered shall be primed prior to installation.”
| What you have | Re-cover? | Section |
|---|---|---|
| One layer, sound, manufacturer-approved for re-cover | Permitted | R908.3.1 |
| Standing-seam metal carrying its own loads | Permitted, no removal required | R908.3.1 |
| Metal panel, metal shingle or concrete/clay tile over wood shake | Permitted, with R908.4 fire separation | R908.3.1, R908.4 |
| New coating over existing spray polyurethane foam | Permitted, no tear-off | R908.3.1 |
| Water-soaked or deteriorated existing roof | Not allowed | R908.3.1.1 |
| Slate, clay, cement or asbestos-cement tile covering | Not allowed | R908.3.1.1 |
| Two or more applications of any covering | Not allowed | R908.3.1.1 |
Which code is this, exactly?
Kentucky’s mandatory residential code is the 2015 IRC, with the Kentucky amendments in the 2018 Kentucky Residential Code superseding any conflicting provision.
815 KAR 7:125, Section 2(1), is the adopting regulation: “Except as provided in subsection (2) of this section, the 2015 International Residential Code for One (1) and Two (2) Family Dwellings (IRC) shall be the mandatory state residential building code for all single-family dwellings, two (2) family dwellings, and townhouses constructed in Kentucky, except that the Kentucky amendments in the 2018 Kentucky Residential Code shall supersede any conflicting provision in the 2015 IRC.” Section 3(1) incorporates both documents by reference — the 2015 IRC and the 2018 Kentucky Residential Code, Third Edition, August 2024, published by the Kentucky Department of Housing, Buildings and Construction.
Two practical consequences. The R908 text above is the 2015 IRC base text; if a Kentucky amendment conflicts with any part of it, the amendment governs, and the amendment document is the one to check on a specific job. And Section 2(2)(a) is worth knowing before anyone argues about paperwork: “Permits, inspections, and certificates of occupancy shall not be required for a single-family dwelling unless required by local ordinance.” The code applies statewide; the enforcement does not, and whether anyone inspects your reroof is a local question.
How we count layers before quoting
Counting applications is the first thing worth doing on any reroof conversation, and it is cheaper than any other step. In general practice the count is read at the edges, not in the field — a rake, an eave, a gable return, or the cut at a pipe penetration shows the stack in cross-section where the surface never will. Two habits save arguments later. First, write the layer count on the quote with where it was observed, because “two or more applications of any type” is a factual finding that changes the scope and the price, and a finding without a location is an opinion. Second, treat a soft or spongy deck as a separate question from the layer count: R908.3.1.1’s first condition is about whether the existing roof is an adequate base, and that can fail on a single-layer roof. Neither habit is a code interpretation and we do not offer one — the building official does that. They just keep a quote from turning into a change order on the second morning.
Common questions about roofing over an existing roof
How many layers of roofing does Kentucky allow?
The code does not set a layer allowance so much as a stopping point. R908.3.1.1 forbids a re-cover “where the existing roof has two or more applications of any type of roof covering,” so a roof already at two cannot take a third by re-cover — it requires replacement down to the deck under R908.3. A single sound layer may be re-covered where one of the R908.3.1 conditions is met.
Can metal go over an existing shingle roof without tear-off?
R908.3.1 permits a re-cover where “complete and separate roofing systems, such as standing-seam metal roof systems, that are designed to transmit the roof loads directly to the building’s structural system and do not rely on existing roofs and roof coverings for support” are installed, and says those “shall not require the removal of existing roof coverings.” The R908.3.1.1 prohibitions still apply on top of that, so a two-layer or water-soaked roof is out regardless of the system chosen.
Does my low-slope roof have to be rebuilt to reach the code slope on a reroof?
Not for the quarter-unit-in-twelve drainage minimum, if the roof provides positive drainage. R908.1 excepts reroofing from that Section R905 design-slope requirement for roofs that drain, and also says secondary emergency-overflow drains or scuppers under R903.4.1 need not be added to an existing roof that drains. Whether your roof actually provides positive drainage is a site finding, and the building official has the final word where a permit is required.
Sources: Sections R908.1 through R908.6 of the 2015 International Residential Code as adopted for Kentucky, read October 11, 2026; adoption and incorporation by reference at 815 KAR 7:125, Sections 2 and 3, Kentucky Legislative Research Commission; 2018 Kentucky Residential Code, Third Edition, August 2024, Kentucky Department of Housing, Buildings and Construction. Code text quoted as published. General information about Kentucky code requirements, not a code interpretation — the building official having jurisdiction decides that.
By Marcos Gil, REALTOR® — Keller Williams Commonwealth · KY Real Estate License No. 296259 · Call or text (859) 310-1209.
Leave a Reply