How a Complete Solar Roof System Fits Together
A complete solar roof has four groups of parts. Active panels generate power. Passive panels cover the areas that don't. Flashings and trim seal the edges, ridges, valleys and anything that pokes through. And the electrical side, wiring plus power electronics, turns what the panels produce into electricity the building can use.
The parts at a glance
| Part | What it does | Who usually handles it |
|---|---|---|
| Active panels | Cover the roof and generate electricity | Roofer, with the electrician |
| Passive panels | Cover the roof where generation isn't wanted | Roofer |
| Flashings and trim | Seal edges, ridges, valleys and penetrations | Roofer |
| Underlayment and deck | Sit under the panels, as the installation instructions require | Roofer or builder |
| Wiring and connectors | Carry power from the active panels off the roof | Electrician |
| Power electronics | Convert the panels' output into electricity the building uses | Electrician |
| Connection to the building | Ties the system into the electrical panel and, where applicable, the grid | Electrician, with the utility |
From the deck up
Start at the structure. On top of the framing is the roof deck, and on top of that the underlayment. The system's installation instructions say what's needed at each layer, so follow those and not habit. The panels go on next, active and passive in the positions the layout drawing shows, and the flashings and trim close everything off.
The electrical side
Active panels produce direct current. Cables carry it off the roof to power electronics, which convert it to the alternating current a building runs on. From there it connects to the building's electrical panel. If the system is tied to the grid, the utility has its own requirements, and they differ from place to place.
Which power electronics you can use depends on the panels. Ask what the system is designed to work with before anyone buys equipment.
The order things happen in
- Layout drawing agreed, showing every panel and the cable routes.
- Deck checked and underlayment installed.
- Panels installed, with cables run as the roof goes on.
- Flashings and trim fitted.
- Electrical equipment installed and connected.
- Inspection and, where it applies, utility approval before the system is switched on.
Questions we get asked
Is a solar roof just the panels?
No. The panels are the visible part. The flashings, the layers underneath and the electrical equipment are what make it a working roof and a working power system.
Why does a solar roof need passive panels?
Because not every part of a roof is worth covering in solar cells, and some parts can't be. Passive panels finish those areas so the roof is complete and looks consistent.
Can I choose any inverter?
Not necessarily. The panels are designed to work with particular power electronics. Check before buying.
Does it need a battery?
A battery is a separate decision. Ask whether the system you're considering can work with one, and what that would involve.
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