Kentucky Roof Code · Penetrations
Solar panels on a Kentucky roof are governed by a code section most homeowners never see, and it is short enough to read in one sitting. Rooftop-mounted photovoltaic systems fall under Section R909 of the Kentucky Residential Code, and R909.3 sends every penetration those panels make straight back to the same flashing chapter that governs a chimney, a vent or a skylight. That single cross-reference is the whole answer to “will the array leak.”
What does the Kentucky code actually say about a solar mount penetration?
R909.3 requires rooftop photovoltaic systems to be installed per the manufacturer’s instructions, and requires roof penetrations to be flashed and sealed in accordance with the roof assemblies chapter.
Section R909.1 provides that the installation of photovoltaic panel systems mounted on or above the roof covering shall comply with that section, Section R324 and NFPA 70. R909.2 requires the system to be designed to structurally support itself and withstand applicable gravity loads under Chapter 3, and requires the roof it sits on to be designed and constructed to support the loads imposed by the system under Chapter 8. R909.3 then states that rooftop-mounted photovoltaic systems shall be installed in accordance with the manufacturer’s instructions and that “roof penetrations shall be flashed and sealed in accordance with this chapter.”
“This chapter” is Chapter 9. R903.2.1 requires flashings at wall and roof intersections, wherever there is a change in roof slope or direction, and around roof openings — and where the flashing is metal, it must be corrosion resistant and not less than 0.019 inch thick, which is No. 26 galvanized sheet. A solar standoff is a roof opening. It is held to that standard, not to a lesser one.
The code does not treat a solar standoff as a special case. It treats it as a hole in the roof — which is exactly how a repair crew finds it three winters later.
Does a panel array change what the roof structure has to carry?
Yes, and in a way that surprises people: the code removes roof live load under the panels, but still requires the structure to work for the case where the panels are not there.
Section R324.4.1 provides that roof structures supporting photovoltaic panel systems shall be designed for applicable roof live load, that the design “need not include roof live load in the areas covered by photovoltaic panel systems,” and that portions of the roof not covered by panels shall be designed for roof live load. It then adds the part that gets missed: roof structures supporting a photovoltaic panel system “shall be designed for live load, LR, for the load case where the photovoltaic panel system is not present.” In plain terms, the framing has to pass both with the array and without it — which matters the day the array comes off for a re-roof.
What about solar shingles rather than mounted panels?
Different section, stricter roofing rules. Photovoltaic shingles are a roof covering, so they land in R905.16 with a minimum slope, a deck requirement and an ice barrier rule.
R324.5 routes building-integrated photovoltaic systems that serve as roof coverings to Section R905, and R324.5.1 sends photovoltaic shingles specifically to R905.16. There, R905.16.2 limits photovoltaic shingles to roof slopes of 2:12 or greater. R905.16.1 requires a solid or closely-fitted deck unless the covering is specifically designed for spaced sheathing. R905.16.3 requires underlayment conforming to ASTM D4869 or ASTM D6757, applied shingle fashion from the eave and lapped 2 inches under R905.16.4. And R905.16.4.1 carries the ice barrier rule: in areas with a history of ice forming along the eaves causing a backup of water, as designated in Table R301.2(1), an ice barrier of two cemented layers of underlayment or a self-adhering polymer modified bitumen sheet must run from the lowest edges of all roof surfaces to a point not less than 24 inches inside the exterior wall line, with an exception for detached accessory structures containing no conditioned floor area.
If you want the broader Kentucky ice-barrier picture, we covered it separately in when an ice barrier is required on a Kentucky roof.
Where do solar-related leaks actually show up on a repair call?
At the attachment points and the transitions around them — the same places the code singles out, for the same reason.
Speaking generally about the craft rather than about any one job: a penetration that was sealed instead of flashed will hold for a while and then stop, because sealant is a maintenance item and flashing is a water-management detail. The code’s own language separates them — R909.3 says flashed and sealed, not sealed. The related details worth checking at the same time are wall intersections and slope changes under R903.2.1, and the cricket requirement in R903.2.2 for any penetration more than 30 inches wide measured perpendicular to the slope. Our notes on kick-out flashing under the Kentucky code and on valley and wall flashing repair cover those two details directly.
Central Roof Repair works on the roof side of this: diagnosing and repairing leaks at existing penetrations, and advising on roof condition before an array goes on or comes off. Electrical work and panel installation belong to a licensed electrical and solar contractor under NFPA 70, which R909.1 and R324.3 both reference.
| Section | What it governs |
|---|---|
| R909.1–R909.3 | Rooftop-mounted PV: compliance, structural support, installation and penetration flashing |
| R324.4.1 | Roof live load with and without the array present |
| R324.5 / R905.16 | Building-integrated PV and photovoltaic shingles as a roof covering |
| R905.16.2 | Photovoltaic shingles limited to 2:12 slope or greater |
| R903.2.1 / R903.2.2 | Flashing locations and metal thickness; cricket over penetrations wider than 30 inches |
Is caulk alone enough at a solar mount?
The code language is “flashed and sealed in accordance with this chapter” (R909.3), and Chapter 9’s flashing requirements in R903.2.1 specify locations and, for metal flashing, a minimum thickness of 0.019 inch. Sealant on its own does not satisfy a flashing requirement.
Do photovoltaic shingles work on a low-slope roof?
Not below 2:12. R905.16.2 states that photovoltaic shingles shall be used only on roof slopes of two units vertical in 12 units horizontal or greater.
Does the code require a cricket above a solar array?
R903.2.2 requires a cricket or saddle on the ridge side of any chimney or penetration more than 30 inches wide measured perpendicular to the slope. Whether a particular array or its attachments meet that description is a question for the installer and the local building official; the rule is written about penetration width, not about panel type.
Last updated: October 18, 2026. Code sections are from the Kentucky Residential Code as adopted from the 2015 IRC; the Commonwealth publishes the code through the Kentucky Department of Housing, Buildings and Construction. General consumer background on rooftop solar is published by the U.S. Department of Energy’s Homeowner’s Guide to Going Solar. Sections read October 18, 2026.
Disclosure: Marcos Gil owns Central Property Services and publishes marcosgilrealty.com and Invest in the Gorge.
By Marcos Gil, REALTOR® — Keller Williams Commonwealth · KY Real Estate License No. 296259 · Call or text (859) 310-1209.
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