Solar Answers → Your Home & Roof
What does your roof need to qualify for solar in Illinois?
No Illinois law sets a roof age, pitch, or material rule for home solar. What the law does fix: installers must be certified by the Illinois Commerce Commission under 83 Ill. Adm. Code Part 468 (with a narrow self-install exception), and every system must meet state and local permitting standards. The rest — remaining roof life, sun exposure, structure — is a per-roof judgment. Most asphalt, metal, and even flat roofs qualify.
Independent public sources we cite and link — The Day Company is not affiliated with or endorsed by any of them.
Is your roof too old for solar?
There's no legal age cutoff — no Illinois statute or rule disqualifies a roof by age. The practical standard is remaining life: panels are built and commonly warrantied to produce for 25 years, so a roof near the end of its own life should be replaced before the system goes on. Otherwise you pay twice later — once to take the array down, and again to put it back.
That second job is real work: a crew detaches the panels and racking, stores them, waits out the re-roof, then remounts everything on fresh flashing and sealing, with re-inspection to follow. It's a genuine, avoidable line item — which is why a good site survey assesses remaining roof life up front, and why many homeowners with a tired roof bundle the re-roof and the install into one coordinated project instead.
Does your roof have to face south?
No — south simply collects the most annual sun in Illinois, so a south-facing surface is the strongest canvas. East- and west-facing roof faces are built on routinely and produce meaningfully, just less than due south. True north faces rarely make financial sense here, and most designs simply leave them out. Direction shapes system size and the math; it almost never disqualifies the home.
Designers regularly combine faces — some panels east, some west — to reach a target size when no single face carries it alone. And if you're in an HOA, remember the association can't bar any roof face from hosting panels; Illinois law protects that specifically. Trees and neighboring buildings are the separate question — that's shade, and it gets its own answer.
Does pitch matter — and can flat roofs work?
Standard pitched roofs — the vast majority of Illinois single-family homes — are solar-ready as-is; racking is engineered for common slopes. Very steep pitches mostly add labor and safety setup, not disqualification. Flat and low-slope roofs work too, using ballasted racking: weighted mounts that tilt the panels toward the sun with few or no penetrations through the roof surface.
The trade-off on a flat roof is weight — ballast is heavy by design, which makes the structural review below matter even more.
Which roof materials work with solar?
Nearly all of them, with different attachment methods. Asphalt shingle — the Illinois default — takes lag-bolted, flashed mounts. Standing-seam metal is arguably the best solar surface there is: clamps grip the seams with zero penetrations. Tile and slate are workable but slower and costlier to mount. And when a roof truly can't host panels, a ground mount moves the array to the yard.
| Roof type | How panels attach | Worth knowing |
|---|---|---|
| Asphalt shingle | Lag-bolted mounts into the rafters, flashed and sealed | The Illinois default — fastest, most familiar install |
| Standing-seam metal | Clamp-on hardware grips the raised seams — no roof penetrations at all | Excellent pairing; the roof often outlasts the system |
| Tile / slate | Specialty hooks or replacement flashing pieces, with careful handling | Fully workable — plan for more labor and a crew experienced with the material |
| Flat / low-slope | Ballasted (weighted) racking, tilted toward the sun | Few or no penetrations; the structural review carries the ballast-weight question |
| No workable roof? Ground mount | Freestanding racking in the yard | Same equipment, sited for sun — needs open ground and local setback compliance |
What structural and electrical checks should you expect?
Two reviews happen before any racking touches shingles: structural — can the framing and decking carry the added load, verified against your local code — and electrical — can your main service panel accept the system. Older homes with smaller 100-amp services sometimes need a panel upgrade first, and if yours does, that work belongs itemized in the solar quote, not discovered mid-install.
This is exactly what the permitting process exists to confirm, so treat it as a feature: ask any bidder how the structural load and main-panel evaluation were done for your specific home, and expect a specific answer.
Will solar void your roof warranty — and who stands behind the holes?
Done right, attachments are bolted into structure and sealed with flashing — the same waterproofing logic as any other roof penetration — and panels typically shield the shingles beneath them from sun and weather. Roofing-material warranties vary by manufacturer, so the protection that matters most in practice is the installer's own workmanship and penetration warranty. Get it in writing before you sign.
Three things to nail down: how long the workmanship warranty runs, whether it explicitly covers leaks at penetration points, and what happens if the roof needs work mid-life. Who holds which warranties long-term also depends on how you buy — owned systems keep everything in your name, while third-party deals split it. The lease vs PPA vs buying breakdown covers that in full.
Who's actually allowed to install solar in Illinois?
Illinois regulates this directly. Since the end of 2013, every entity installing distributed generation — which includes rooftop solar — must be certified by the Illinois Commerce Commission under 83 Ill. Adm. Code Part 468 before installing anything in the state. The one exception is a true self-install: your own system, on your own premises, installed without the assistance of any other person.
That self-install bar is strict — "without the assistance of any other person" is the rule's own phrase, and it means exactly that. And certification isn't paperwork trivia: state law ties net metering to it — a utility can't provide net metering service for your system unless you provide the confirmation these installer rules require (220 ILCS 5/16-128A(c)). An uncertified install can cost you the bill credits the system was sized around. So ask any bidder for its ICC distributed generation installer certification — and note that it's separate from Illinois Shines Approved Vendor status. A legitimate offer can show you both.
Do you always need a permit?
Yes. Solar energy systems must meet the standards and requirements of state and local permitting authorities — that's written directly into Illinois law (765 ILCS 165/25) — and nothing substitutes for it, including HOA approval. Your city or county building department is the authority; your installer typically pulls the permits, but they're issued for your property.
Utility interconnection is its own separate track on top of permitting: an application to ComEd or Ameren and, eventually, permission to operate before the system switches on. The ComEd Solar Guide walks the northern-Illinois version of that process. And if an HOA is in the picture, its approval runs on a separate track too — it can shape roof-face configuration, never permits.
Roof Requirements FAQ
Is there a legal roof-age limit for solar in Illinois?
No. No Illinois statute or rule disqualifies a roof by age. The law regulates who installs the system and requires it to meet state and local permitting standards — roof age is a practical engineering judgment made per home, weighing how much life the roof has left against how long the system will sit on it.
Should I replace my roof before installing solar?
If it's near the end of its life, yes. Panels stay up for decades, and re-roofing under an existing array means paying a crew to detach and store the system, re-roof, then remount, re-flash, and re-inspect everything. Replacing a tired roof first — or bundling both jobs into one project — avoids that entire second round.
Can solar work on an east- or west-facing roof?
Yes, routinely. South collects the most annual sun in Illinois, but east and west faces are built on all the time and produce meaningfully — designers often combine faces to reach the target system size. True north faces rarely make financial sense and are usually left out of the layout entirely.
Does solar work on a flat roof?
Yes. Flat and low-slope roofs use ballasted racking — weighted mounts that tilt panels toward the sun with few or no penetrations through the roof surface. The trade-off is weight: the structural review has to confirm the roof can carry the ballast, which is exactly what the permit process checks.
Can you put solar panels on a metal roof?
Yes — standing-seam metal is one of the best solar surfaces available. Mounting clamps grip the raised seams directly, so nothing penetrates the roof at all, and a metal roof's long service life pairs well with a long-lived system. Other metal profiles work too, with penetrating mounts and careful flashing.
What about tile or slate roofs?
Workable, with more labor. Tile and slate are brittle underfoot and mount differently — crews use specialty hooks or replacement flashing pieces and move slower to avoid breakage, which shows up in the bid. If a quote treats a slate roof exactly like asphalt, that's a reason to question the rest of it.
Will solar panels void my roof warranty?
Not automatically — roofing-material warranties vary by manufacturer, and properly flashed penetrations are standard roofing practice. Panels typically shield the shingles beneath them from sun and weather. The protection that matters most is the installer's written workmanship and penetration warranty: get its length and leak coverage in writing before signing.
Can I install solar myself in Illinois?
Legally, yes — narrowly. Illinois exempts a self-installer from ICC certification: someone installing a system for personal use, on their own premises, without the assistance of any other person — the rule's own words, and it means exactly that. Anyone else touching the install puts you outside the exception, and net metering requires the certification confirmation either way.
Do I need a permit even if my HOA approves?
Yes, always. Illinois law says solar systems must meet the standards of state and local permitting authorities — HOA sign-off never substitutes (765 ILCS 165/25). Your installer typically handles the permit filings, and utility interconnection approval from ComEd or Ameren runs as its own separate step before the system switches on.
What if my roof can't qualify at all?
You still have paths. A ground mount puts the same equipment on freestanding racking in the yard, sited for sun instead of constrained by the roof. And if neither works, community solar lets you subscribe to an off-site project without installing anything — heavy-shade homes often land there.
Related answers
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Sources
- 83 Ill. Adm. Code Part 468 — Distributed Generation Installer Certification, full text (Illinois General Assembly / JCAR)
- 220 ILCS 5/16-128A — Certification of installers of distributed generation (ilga.gov)
- 765 ILCS 165 — Homeowners' Energy Policy Statement Act (permitting standards, §25) (ilga.gov)
How to cite: "Illinois Solar Roof Requirements: Age, Pitch, Type (2026)," The Day Company, https://theday.company/answers/solar-roof-requirements-illinois, reviewed July 2026.
Changelog: July 18, 2026 — v1 published.