Solar panels and leaky roof

aminaelis
aminaelis Registered Users Posts: 14 ✭✭
Recently, I talked to one of my new neighbors and he said that in Arizona where he lived before many homeowners experienced roof leaks cause by photovoltaic system. I haven't ever heard nor read anything like this before. According to my neighbor, the cost of fixing the roof made the whole array much more expensive than paying monthly electricity bills to energy company.    

Do you think it was because of the roofing material or the quality of service? 

Does anyone experience the same thing? 

Comments

  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    Mine never leak because of the solar system, but did leak where the original roof flashing was done completely wrong by the builder. It hurts nothing to have the roof checked out before adding solar.  I had my tile roof underlayment done with a double layer of 40 pound underlayment. BTW it cost about $6K for the solar tear off and reinstall.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    One of my roofers was thinking of getting into installing GT solar systems. He saw the design and electrical as easy, and a good chunk of his work was removing and replacing solar panels because of leaks.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • aminaelis
    aminaelis Registered Users Posts: 14 ✭✭
    @solar_dave: Yeah, I thought the same thing. It surprised me to hear this. My neighbor seemed so convinced that solar arrays actually damage roof. Which made me think if after 10 or 15 years the roofing material does not start to wear off thanks to solar panels attached to it. Afterall, they were not meant to be there, when the roof is put in place. 6K is a significant sum of money... 
  • aminaelis
    aminaelis Registered Users Posts: 14 ✭✭
    edited October 2017 #5
    @BB. so, it does happen probably more often than anyone mentions or writes about! :/

    I myself do not have PV system installed yet, only solar water heater, which works well for me. But I am trying to learn more about this emerging technology, because it gets a lot of publicity recently. I found pretty clear overview of the main advantages of going solar here: https://greentumble.com/solar-energy-pros-and-cons/.  This really makes me want to install solar panels right away. 

    But as I said, there are also problems (such as the chance of roof damage...) that are not so often described on internet. It only happened by coincidence that I started to chat with my neighbor about installing solar. And he is skeptical about them. 
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,039 ✭✭✭✭✭
    Flashed correctly, there shouldn't ever be a problem. Actually the section of roof covered by the array is not likely to ever burn out being that it is always shaded. The south side of roofs are the first to burn out (in the northern hemisphere) so depending on the percent of roof covered by solar panels you can actually get a longer life out of your comp roof with solar.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • aminaelis
    aminaelis Registered Users Posts: 14 ✭✭
    @littleharbor2 I guess, the roofing problem happens with older technologies or materials, then...(?) Not everyone can probably afford to maintain their whole house in top form, but tries to get the PV system installed anyway.   
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,039 ✭✭✭✭✭
    Older technology, if you could call it technology, used to consist of an L bracket lagged down into a bed of mastic will eventually leak every time. Proper flashing will outlast the roof and array and when done correctly will not leak.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • peteoldman
    peteoldman Registered Users Posts: 5 ✭✭

    That is why I went with  a ground mount .I have done roofing for about 35 years and know the first place to leak is any atachment thrue the roofing
  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    aminaelis said:
    @solar_dave: Yeah, I thought the same thing. It surprised me to hear this. My neighbor seemed so convinced that solar arrays actually damage roof. Which made me think if after 10 or 15 years the roofing material does not start to wear off thanks to solar panels attached to it. Afterall, they were not meant to be there, when the roof is put in place. 6K is a significant sum of money... 
    While $6K is a significant amount of money it was less then 10% of the original solar build and the house worth way more, the total cost for the roof was about $20K including the solar work.  I could have done the reinstall cheaper if I would have stayed wit the stud through the tile and mastic sealer, but I opted for proper standoffs with a double flashing, one at the underlayment level and one at the top of the tile level.
  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    I and a lot of others in New England put WR Grace Storm Shield (or equivalent) under our roof shingles or underneath metal roofing if they plan to install PV or just want a long lasting roof. It self heals from punctures and is quite reliable for providing a waterproof membrane under whatever is on top. Its also very easy to patch into. its not a substitute for a properly designed flashed in roof mount but it does provide a significant amount of secondary protection. I have installed both solar thermal and PV on my roof so equipped and have had zero issues.

    As an aside, the majority of standing seam metal roof installers in my area will not install standing seam without installing storm shield on new roof decks or stripping the old one and installing the membrane. Effectively if the standing seam leaks it just runs down the membrane under the steel and out the soffits. Asking a single product to do Thermal, UV and waterproofing all in one product is asking a lot, its far better breaking it up into two products. We also have something called Ice damming (I expect not an issue in the SW) and this product effectively prevents it from happening.

    I would speculate that if and when installation details are available for the Tesla Solar roof that they will probably do an underlying membrane. 
  • 706jim
    706jim Solar Expert Posts: 514 ✭✭✭✭
    Something not yet mentioned is the cascading effect of water running off of the solar panels. Glass panels absorb absolutely no water which ends up overloading the shingles directly below said panels. At my place, I have two sets of panels on a 4/12 roof placed as close to the roof peak as possible. I'm sure the shingles under the arrays are just fine, but the ones directly below them will leak during a heavy rainstorm, just due to all the water cascading down onto the last 4' of shingles. I'm still pondering the use of metal instead of asphalt shingles and noticed that metal roofs are quite common in British Columbia mountain buildings.
    Island cottage solar system with 2500 watts of panels, 1kw facing southeast 1.3kw facing southwest 170watt ancient Arco's facing south. All panels in parallel for a 24 volt system. Trace DR1524 MSW inverter, Outback Flexmax 80 MPPT charge controller 8 Trojan L16's. Insignia 11.5 cubic foot electric fridge. My 30th year.