Roof Life vs. Solar Life

Roof shingle showing wear

Composition shingle showing wear on the edges

Have you thought about how long a solar photovoltaic system lasts up on the roof, exposed to the elements year round?  The performance warranty on solar panels is generally 25 years but there are solar panels produced 30 years ago that are still producing power as if new.  One example is the 33 watt Arco panels that were produced around 1980 that were the leading edge of powering off-grid homes in Northern California.  These panels have been documented to produce just as much wattage now as when new.

Can your roof last as long as a solar system?  Not likely unless you have installed a roof system that has a long warranty.  If your current roof needs replacement now, then it’s a no-brainer to replace it before the solar system goes on.  You want to avoid the expense of solar system removal and reinstallation just to fix your roof.

Here are some points to consider:

  • Can’t afford a new roof before the solar goes in?  Then install a new roof only on the roof section where the solar panels will be.  We mean the roof section from ridge to eave and from one rake edge to the other, not just under the solar panel footprint.  You can do the rest of the roof when you have the funds.
  • Upgrade your roofing material for longer performance.  Avoid roofing backed by a short warranty and get the longest manufacturer’s warranty you can afford.
  • Avoid tar and gravel roofs, please!  These are generally for low-slope roofs (some people call these “flat” roofs) and they don’t last long enough when paired with a solar system.  At a minimum, install Modified Bitumen Asphalt (MBA) roofing or Built-Up (BUR).
  • If your current roof is composition shingle, look closely.  See any fiberglass matting showing?  If the edges are worn, you may see white “threads” showing, which is the fiberglass.  Replace the roofing before you install solar.
  • Have an older tile roof for a while?  Tile lasts a long time but take a look at the underlayment to ensure it is still in good shape.  Water tends to leach out the oil in the felt paper, drying it out until it resembles flaky paper.  You’ll need to pull the tile and replace the underlayment.  Use the new synthetic alternatives  instead of traditional felt paper and replace the wooden battens with the newer designs that let water flow freely through the battens.
  • Have a foam roof?  Install the solar standoffs but have your original roofer return to backfill with more foam to maintain the roof warranty.

Paying attention now to the needs of your roof before installing a solar system will give you peace of mind.

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