Replace gutters and roof before panels, not after
Solar panels are expected to last 25 years or more. Removing and reinstalling them later to fix the roof or roof edge costs real money. If your roof or gutters are near the end of their life, replacing them before the panels go up is usually the smart order. That includes checking fascia and drip edge, which are hard to reach once panels are installed near the eaves. See new roof, new gutters? and fascia repair before new gutters.
Fire-code pathways and setbacks
Building and fire codes limit where panels can go. The International Residential Code (section R324.6), as summarized by state agencies such as the Minnesota Department of Labor and Industry and NYSERDA, generally requires clear pathways at least 36 inches wide from the lowest roof edge to the ridge for firefighter access, and clear setbacks along ridges (18 or 36 inches depending on how much of the roof is covered). Local codes vary. These rules also leave some room to reach the roof edge and gutters, but panels often still sit close to the eaves elsewhere.
How panels change roof runoff
- Concentrated flow: water runs off the smooth glass of panels and drops off their lower edges in sheets, often onto a narrow strip of roof above the gutter. In heavy rain, gutters below large arrays can overflow more often.
- Snow sliding: snow slides off glass panels faster than off shingles, in sudden sheets that can bend or tear gutters. Snow guards below arrays and stronger gutter attachment help. See snow load and gutters.
- Debris trapped under panels: leaves, needles and seeds collect under and around panels and wash into gutters in storms.
Where arrays are large, 6-inch gutters with 3x4-inch downspouts and heavier hangers are worth considering. See 5-inch vs. 6-inch gutters.
Access for maintenance
Panels make it harder to clean gutters and inspect the roof edge from the roof. Most gutter work is done from a ladder, but ladders must never lean on panels or their wiring, and some roof edges below arrays are hard to reach. Gutter guards reduce how often anyone needs to get up there. See are gutter guards worth it?
Critter guards vs. gutter guards
Pigeons and squirrels love the sheltered space under solar panels. Solar installers often add mesh critter guards around the edge of arrays to keep animals out. These are different from gutter guards, which cover the gutter. Both are useful; they work together to keep nests and debris out of the gutters. See gutters and pests.
Leaves and needles under panels
Under trees, leaves and pine needles pile up behind and under panels, especially on the uphill side of the array. In heavy rain, that debris washes down in clumps and clogs gutters and downspout outlets below the array. Fine-mesh guards that fasten to the gutter, plus strainers at the outlets, keep this from turning into overflow. Periodic removal of debris from around the array by the solar company also protects the panels and wiring.
Coordinate the trades
- Tell the solar installer about planned gutter work, and the gutter installer about planned solar.
- Make sure panel mounts and conduit do not interfere with gutter hangers, guards or downspouts.
- Ask whether any work at the roof edge affects the solar or roof warranty.
- Keep ladders and gutter work clear of solar wiring.
- Photograph the roof edge and gutters before panels go on, for future reference.
Keeping panels clean
Many homeowners rely on rain to rinse panels. That rinse water, carrying dust and pollen, ends up in the gutters. Some also have panels professionally washed. Make sure any washing does not flood clogged gutters or send debris into downspouts. Guards and strainers at downspout outlets help.
Rainwater harvesting with solar
Panels do not prevent rainwater harvesting; the water still reaches the gutters. Glass panels are a clean collection surface, though water should still pass through a first-flush diverter. See rainwater harvesting from your gutters.
Warranty questions
Solar installers usually warrant their roof penetrations against leaks for a period of years, and roof manufacturers have their own warranty terms. Work at the roof edge, such as replacing gutters or adding guards that slide under shingles, can raise questions about who is responsible if a leak appears. Ask both the solar installer and the gutter installer how their warranties treat each other’s work, and keep records of what was installed and when. See gutter warranties explained.
Removing and reinstalling panels
If gutters or the roof edge need major work after panels are installed, some panels may have to be removed and reinstalled. That is usually done by a solar company, often for a fee per panel, and it must be scheduled around the gutter or roofing work. Knowing this in advance is the best argument for doing roof and gutter work first. Ask your solar installer what removal and reinstallation would cost before you sign.
Batteries, inverters and wiring on walls
Solar systems add conduit, disconnects and sometimes batteries or inverters on exterior walls. Keep downspouts from discharging onto or next to this equipment, and make sure new downspouts do not block access to disconnects. Tell the gutter installer where the electrical equipment is before downspout locations are chosen.
Ground-mounted arrays
If the roof is shaded, old or complicated, a ground-mounted array avoids many of these conflicts. It leaves the roof edge and gutters easy to reach, and snow and runoff from the panels fall on the ground rather than into gutters. It needs yard space and usually more trenching for wiring, but it separates the two systems completely.
Common questions from installers
When you get gutter estimates on a home with solar, expect the installer to ask how close panels come to the eaves, where conduit runs, whether there are critter guards, and whether any part of the roof edge is inaccessible. Photos from the ground and a roof plan from the solar company help them give an accurate price and avoid surprises on installation day.
Checklist before going solar
- Is the roof less than halfway through its life? If not, replace it first.
- Are gutters, fascia and drip edge sound?
- Are gutters sized for concentrated runoff from the array?
- Do you want guards installed now, while access is easy?
- Are snow guards needed below the array?
- Who will you call for gutter work later, and how will they reach the edge?