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  • Snow damage

    I had lg solar panels installed on my colonial last summer. The house has a covered front porch. In order to use all available space my installer placed the panels on the main roof and the porch roof. This winter i have had my house shaken as the snow slides off the roof to the porch roof then ground below. First time i sprang up to look thinking the porch panels were destroyed. Found out they were fine. Also remebered I was told the panels could handle the snow. I think almost 6 feet. Decided to stop worrying. Today after another snow storm the roof let loose again. This time one panel was shattered. My question is am I going to be stuck paying for this. I feel if this was a risk I should of been informed. If i am left with the cost it is going to be very expensive everytime it snows. Also is there anything that can been done to prevent this.

  • #2
    Howdy, first thing is to call your installer ,see what they propose. Sounds like it may have been a bad call to put the panels on a porch roof, can you tell if the problem will keep occurring at the same point. If so you may need to remove panels from that spot, perhaps they can be relocated to another area of roof?

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    • #3
      Snow will definetly keep landing on porch if it slides off roof. As far as relocated not really any other roof space available. Yea i will call the installer just want to know what people think or if anyone has a similar setup with or without issues. That way if installer says no i have more statistic on whether damage of this source is normal.

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      • #4
        There are really only three options, move the panels, clear off the accumulation before it builds up to damaging levels, or build rails on either side of the panels that will allow you to slide in some sheets of 3/4 ply to cover them before a big snow storm. Solar panels can take some abuse, im 210 lbs and i walk on them every day at work without a problem. They flex under the weight but they don't crack. That being said, solar panels are made of glass and 6 feet of snow and ice slamming onto them from height will easily crack a piece of glass. If the pitch of your roof has let loose large amounts of snow in the past it should have been obvious that the location above your porch was not a good spot for them. The installer was correct in stating that they can take some abuse but not hundreds of pounds falling on them.
        Last edited by Unona1444; 03-19-2017, 11:22 PM.

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        • #5
          Roof never let loose before. Letting loose is a direct result of the panels. There was at most only a foot of snow on the above panels at most. As far as the installer statting they can take abuse I do agree however I also feel an installer that has been around over a decade should know ahead of time if a setup of this nature will lead to issues. Lastly we have had 5 to 10 storms this year with no issue. I would also imagine many people have this setup. I am wondering if it is a normal occurence or possibly a defective panel. If people have this happen all the time with no broken panels then I know its a defective panel and not a poor install.

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          • #6
            Snow sliding and falling any distance can do damage or be dangerous; I had to build a lower roof over security
            equipment to avoid repeating damage. Its probably more likely to slide in big hunks off slippery panels, than a
            rough roof. I have seen some sort of stakes on metal roofs that seem to be either to hold up slides, or break
            them up into smaller chunks before dropping.

            Also had a windshield broken by snow plowed off the upper level of a bridge. Bruce Roe
            Last edited by bcroe; 03-20-2017, 01:08 AM.

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            • #7
              In spite of what you may have been told, impact loads from snow are probably not part of any warranty, just like rocks and golf ball strikes. I seriously doubt the panels were/are defective. Move the panels to a safer location or leave them there and take measures to avoid the snow impact. Snow loading is one thing but what happened seems like it could have been headed off. Expecting it won't or can't happen again without measures to avoid a recurrence is unrealistic.

              If I still lived in a cold climate, I'd pay careful attention to what Bruce Roe has to offer in the way of building array's in snowy climates.

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              • #8
                I would suggest you have the installer put up a snow guard at the bottom edge of the upper panels. Solar panels, like metal roofing are very slick and the snow will slide off frequently. If you only remove the panels on the porch roof, you are going to end up with a damaged roof at some point. Large quantities of snow continuously falling on the porch roof is something it was not designed for.
                The snow guard will prevent avalanches, but you will lose some production, as the snow will cover the panels until it can melt, rather than slide off.

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                • #9
                  What emartin00 said. You can install snow fences on the roof that will prevent the snow from sliding off. As he also pointed out, the panels will stay covered until it melts or someone shovels the snow off.

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                  • #10
                    Thanks. I have notified my installer he is looking into it. They seem to not believe me it was snow coming from above because they keep saying it looks like an impact. Unless a meteor hit it nothing beside snow has fallen on it. I also asked if they ever seen snow from above falling damage a panel and they say no. Thanks for the ideas. First I will deal with who is getting stuck with the repair cost then what can be done to prevent future issues. I can deal with waiting for snow to melt as opposed to replacing panels every year.

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                    • #11
                      Snow sliding down a roof tears off vent pipes, no reason to think a rooftop avalanche would not hurt glass underneath it,
                      Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                      || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                      || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                      solar: http://tinyurl.com/LMR-Solar
                      gen: http://tinyurl.com/LMR-Lister

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                      • #12
                        I've seen video of snow falling off of large commercial metal roof and destroying a car before. I assure you, it can break a solar module.
                        You didn't specify how many rows of panels you have on the upper roof, but assuming you have 2 rows, you could potentially have over 600lbs of snow falling onto the panel below

                        Rough calcs: Panel dimensions: 5.25X3ft = 15.75sqft -> *2 rows = 31.5sqft Snow load =20lbs/cuft (assume 1ft depth average snow density) -> 31.5cuft*20lbs/cuft = 630lbs of snow

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                        • #13
                          Originally posted by emartin00 View Post
                          I've seen video of snow falling off of large commercial metal roof and destroying a car before. I assure you, it can break a solar module.
                          You didn't specify how many rows of panels you have on the upper roof, but assuming you have 2 rows, you could potentially have over 600lbs of snow falling onto the panel below

                          Rough calcs: Panel dimensions: 5.25X3ft = 15.75sqft -> *2 rows = 31.5sqft Snow load =20lbs/cuft (assume 1ft depth average snow density) -> 31.5cuft*20lbs/cuft = 630lbs of snow
                          Don't forget sometimes you get a layer of ice on top of that snow if it turns to rain and then temperatures gets below freezing again. Adds a lot of weight to that avalanche hitting the panels below.

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                          • #14
                            Originally posted by emartin00 View Post
                            I've seen video of snow falling off of large commercial metal roof and destroying a car before. I assure you, it can break a solar module.
                            You didn't specify how many rows of panels you have on the upper roof, but assuming you have 2 rows, you could potentially have over 600lbs of snow falling onto the panel below

                            Rough calcs: Panel dimensions: 5.25X3ft = 15.75sqft -> *2 rows = 31.5sqft Snow load =20lbs/cuft (assume 1ft depth average snow density) -> 31.5cuft*20lbs/cuft = 630lbs of snow
                            It's not only the dead weight of snow or other loading, it's the (mass*velocity) product = momentum, and impact (how long the momentum transfer to the array takes (soft landings might do less damage because they take longer)). An array may easily take a 630 lbm distributed dead load, particularly if applied slowly - as in, say, a snow storm. Drop 630 lbm mostly distributed onto an array from a 1 inch height, or maybe even 1 foot and things may well still be OK, particularly (and for example only) if the array being impacted is mounted on "soft" springs to slow down the rate of impact. Drop the load from, say, a 6 ft. height and the momentum and impact will most likely cause damage, particulary if there's ice in the applied load from an ice dam falling from a roof above the array.
                            Last edited by J.P.M.; 03-21-2017, 05:08 PM.

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                            • #15
                              I have panels on my roof and panels hanging off a wall underneath them. The lower panels get tagged on occasion by small chunks but generally a big slide will just clear the lower edge of the wall mounts as long as I have them in their winter angle (30 degrees). From a solar point of view I should have already raised the wall mounts to spring angle (45 deg) but they stay down until the chance of significant snow goes away due to the this issue.

                              I had an 18" snow storm last week, the roof panels were buried plus a 30" drift formed over the top corner and top edge of the panels. They are on second story roof so I can only get to the bottom edge of the panels and 18" wide stretch of roof shingles that are exposed below the panel. I have standard plastic roof rake and four 5' pole sections. Its definitely quite floppy with 4 poles but I can usually get the snow off. Usually the snow burying the panels stays in place for few hours but on this day the snow covering 3/4 of the panels came down with a thump just as I stepped back. I wasn't so lucky with the top of the panels under the drift, it took a couple of days and I wasn't there when it finally let loose. I am not worried much as the trajectory lands just clear of the wall mounts. I find that exposing that stretch of shingles and the lower edge generally gets the snow to let loose faster as once the sun comes out the heat from the shingles and the lower exposed section of the panels tends to get some heat under the rest of the array. The key is to try to get it slide down quickly before it consolidates into frozen chunks as that's what usually is bad for a panel.

                              There are all sorts of snow brakes available for steel roofs that I expect you may be able to retrofit

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