Solar panels are designed to last around 25 years. Roofs in Southern California often do not. If you install a system on a roof with a few years left, you will eventually pay to remove the panels, re-roof, and reinstall them. That cost is avoidable with a little planning.
The simple rule
If your roof has fewer than about 10 years of life left, replace it first or do both together. If it is newer than that and in good condition, panels can go straight on.
The grey area is a roof with 10 to 15 years left. There the decision depends on the covering, the condition of the flashing and whether you plan to stay in the house. We would rather inspect and tell you the roof is fine than sell you work you do not need.
How to judge the roof you have
- Age. Asphalt shingle roofs in this climate typically last 20 to 30 years. Find the permit record or the last invoice if you can.
- Surface condition. Curling, cracked or missing shingles, bald patches where granules have worn away, cracked or slipped tile.
- Granules in the gutters. A roof shedding its surface is near the end of its service life.
- Attic signs. Daylight through the deck, stains on the underside, damp insulation.
- Flashing. Rust, gaps or sealant doing a job that metal should be doing.
What removal and reinstallation costs later
Taking a system down and putting it back is not a small line item. You pay for labour on both ends, new mounting hardware and flashing, an electrician to disconnect and reconnect, and in many cases a new permit. Doing the roof first turns two projects into one.
Doing both as one project
When roofing and solar are planned together, several things improve at once:
- Mounting points are planned with the roof layout rather than worked around it.
- Penetrations are flashed into the new roof as it goes on, which is a better detail than retrofitting later.
- One schedule, one point of contact and one crew sequence instead of coordinating two companies.
- The roof warranty and the solar installation are not pointing at each other if a leak appears.
That last point matters more than people expect. When a separate solar company drills into a roofer’s work, a later leak often turns into an argument about responsibility. One company doing both removes the argument.
Questions worth asking any solar installer
- Did you inspect the roof, or only measure it? A satellite measurement tells them panel layout. It tells them nothing about the condition of the covering.
- How old is the roof, in your assessment? An installer who cannot answer has not looked properly.
- Who is responsible if a leak appears at a mount? Get the answer in writing, especially if roofing and solar come from two companies.
- What flashing is used at the penetrations? This is where retrofit arrays leak.
- What happens if the roof needs replacing in five years? Ask for the removal and reinstall cost now, while you are still choosing.
Timing when the roof is borderline
If the roof has ten to fifteen years left, two things decide it. The first is how long you plan to stay: if you will sell within a few years, the removal and reinstall problem becomes the next owner’s, and that shows up in negotiations. The second is the condition of the details rather than the field. A covering can look sound while the flashing at the chimney and valleys is at the end of its life, and those are the areas an array makes harder to reach later.
Where it is genuinely borderline, we will say so rather than push the bigger job. Sometimes the answer is to replace one slope, the one carrying the array, and leave the rest for later.
What if the roof is fine?
Then leave it alone. A sound roof with 15 or more years left is a good platform for panels. We will say so, note anything worth watching, and get on with the solar design. You can read how we approach solar and battery installation and roof replacement.
Tile roofs need a specific approach
On concrete and clay tile, the tile usually outlives the underlayment beneath it. If your tile roof is 20 years old and the underlayment has never been replaced, that is the work to do before panels go on, even if the tile itself looks perfect. See why tile roofs leak for the detail.
Common questions
Can panels be installed on a tile roof?
Yes, with the right mounts and flashing. The work is more detailed than on shingle, so experience matters.
Will panels damage my roof?
Correctly flashed mounts should not. Poorly sealed penetrations are the usual cause of leaks around arrays.
Do panels protect the roof underneath?
They shade part of it, which helps a little. They do not extend the life of a roof that is already failing.
If you are weighing up the timing, call (888) 271-7675 or book a free inspection. We will tell you how much life the roof has left before you commit to a solar design.