Going Solar? What about your roof?

If you spend any time driving around San Diego you can’t help but notice the dozens of solar companies with marked vehicles or the thousands of houses with solar panels on their roofs. And why wouldn’t there be? With over 3000 hours of sunshine per year, San Diego is the perfect place for a solar power system.

If you are thinking about solar, there are a number of things that come into play, and one of the big ones is the condition of your roof. If your solar provider, or potential solar provider, doesn’t complete a roof inspection or suggest you have your roof inspected by a roofer, that should be an immediate red flag. The solar panels that you will be getting are guaranteed for 30 years, so you probably want to know that your roof will last the same. Most companies will charge up to $4,000 to have a system removed and re-installed, so it is best to make sure the roof is sound before the system is put on your roof.

Depending on the type of roof you have, there are a number of things that you should be aware of. The first is, is your type of roof suitable for solar stands? The types of roof that we would recommend against installing on are clay tile, lightweight concrete and fiber cement. We find that all of these materials are far too fragile to have a solar install on and you will experience a large amount of broken tiles, which will make the roof more susceptible to failing. If you do have one of these types of roofs, the best course of action would be to have an area of asphalt shingles installed in the solar area, and then the tiles re-installed around the array in a “picture frame”. If done properly, it is nearly impossible to tell from a distance that there is anything but tile on your roof.

Now, for the kinds of roof that it would be okay to have a solar system installed on.

Tile Roof

The first line of defense on a tile roof is the tiles themselves. If you have broken tiles, you are exposing your roof to the elements and are much more likely to end up with leaks down the road. So, if there are broken tiles, we would recommend at the very least having those fixed.


After the tile it is the paper that is left to keep your home protected from leaks. Over time the felt paper wears out for a number of reasons. From exposure to sunshine if there are slipped or broken tiles, to water damage if the roof isn’t properly installed. If the felt paper is showing any significant amount of wear it is important that you have a lift and relay (The replacement of the felt paper and re-installation of the existing tile) to increase the longevity of your roof.


Another common source of leaks on tile roofs is over-exposed courses. Manufacturers specify that tiles should be overlapped at least 3”. When the tile is not installed to these specifications the nail is exposed, which could lead to rusting, as well as water going through the nail hole and through the underlayment. (Most tiles are “17, so the exposed portion of the tile should be no more than 14”. Some tiles are longer or shorter, but 17” is the most common length.

  Another possible cause of leaks and something that should be corrected prior to a solar installation is a closed valley. If the tile is aligned closely together in the valley of your roof it could lead to a build-up of debris as well as being improperly constructed to allow the water to flow properly.

Yet another recommendation when it comes to tile roofs is to make sure that all of your pipes are double flashed. It used to be Standard Operating Procedure to simply apply cement around the pipes, which over times cracks and leads to leaks. The proper way to handle roof penetrations on a tile roof is for there to be one flashing under the tile, the primary flashing, and another flashing on top of the tile, the secondary flashing. This allows for added protection of water getting under the tile and leading to leaks.


One final thing of note on tile roofs is the lack of weather block under the ridge trim. If cement, or nothing, has been used, it will eventually lead to water entering and running every which way under the tile and causing leaks. It is best to have a Solite weatherblock installed under the hip and ridge trip.


The best way to have everything addressed, while still saving some money, is to have a lift and relay completed. It will provide fresh paper, new dual flashing on your pipes, the opening of any closed valleys and the installation of weatherblock under the ridge trim. If done by a reputable roofer, this will carry a 15-year workmanship warranty and in reality will last as long as your used tile does.

Asphalt Shingle Roof

The other major roofing material used on roofs throughout San Diego is Asphalt Composition Shingles. As long as you are hiring one of the reputable and experienced solar contractors in San Diego there should be no problems installing solar stands on a slightly aged shingle roof. Ideally the stands would be installed when the underlayment is exposed, before the shingles are installed, but we know it isn’t always realistic to get a new roof. Most of the solar companies are experienced in properly sealing the penetrations from their solar stands on shingle roofs.

As for what problems to look for when considering installing solar on your shingle roof, there are many and I will discuss them below.

The first sign of a problem is extreme wearing of the material. Until recently most shingles were given a 25-30 year life span and that is what was guaranteed by the manufacturer. What this means is that if your roof is nearing 10-15 years old then it may be worth examining the cost of a new roof if your solar system will be guaranteed for 30 years. Nowadays shingles are warrantied for 50 years, and when installed by a GAF Master Elite Installer the workmanship is guaranteed for 25 years. If you see cracking on the shingles, or on the ridge caps, it would be advisable to install a new roof prior to solar installation.


Another sign that your shingle roof may need to be replaced, or have some repairs completed, is the lack of drip edge at the eaves and gable ends. For a shingle roof to have been properly installed it needs a metal flashing, drip edge, at the roofs ends to prevent the possibility of water penetrating the underlayment. It is also a red flag if there is no flashing at the point the shingles meet a chimney or a side al. Without this metal piece the water has nowhere to go but under the shingles. When the metal flashing is installed the water runs down it toward the edge of the roof and helps avoid further leaking.


The final red flag I will discuss on shingle roofs is a poorly flashed vent. Like the tile roof, shingle roof vents should be flashed with a metal flashing. If there is caulking or cement around the pipe it should be switched out and may be a sign of a poorly installed roof system.


The other types of roof that would be okay to have solar installed on are flat roofs and metal roofs. As long as neither is showing great wear or damage they both have the longevity to handle solar panels. A few potential problems on flat roofs are extreme wear and poorly flashing pipes, as discussed with the other types of roofing. The biggest problem on a metal roof would be dented panels.

As you can see, there is a lot of thought that needs to go into if your roof can handle solar. But with all the sunshine San Diego gets it is surely worth considering. If in doubt, it is best to have a licensed roof professional out to take a look at your roof. And it may be best to have a second opinion if the solar provider says your roof is fine.

Mark Anthony Construction and Roofing is Located in San Marcos, CA. Mark has been in the roofing industry since 1973. If you need your roof in San Diego County inspected for a potential solar install, call 760-803-7534 today.

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