How to protect gutters from ice slides?

RegGuheertRegGuheert Solar Expert Posts: 102 ✭✭✭✭
I was showing my neighbor our ongoing 9.87 kW installation the other day and he asked me a question about something which I had never considered. Being from Michigan, he was wondering how I was going to keep the snow and ice from sliding off the new solar panels and tearing off the gutters. My response: :confused:

Seriously, I had not thought of this issue, but I know it can be a real problem. In the past snow and ice did not slide off the roof because it has shingles. Once we cover that area with glass, we may have a very different situation.

Here is a picture of the ongoing installation:

attachment.php?attachmentid=1508&stc=1&d=1291636508

For reference, the linear distance from the bottom of the panels to the top is 16'4" (5.0m). The slope of the roof is 10-12 (~40 degrees).

The panels over the garage will extend all the way down to the gutter. Since I have some concern that *water* will overshoot the gutters once the panels are in place, I expect that snow and ice will do the same. The concern lies with the roof on the right. The panels stop approximately one foot up the roof from the gutter. Any slides from the panels would likely impact the gutter directly. Perhaps the only saving grace there will be the fake dormer which might break up the bulk of any slide.

Anyway, does anyone have any thoughts on this subject? If you have built something to prevent gutter damage from ice slides following PV installation, can you please show me what you have done?

TIA!

Reg

Comments

  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: How to protect gutters from ice slides?

    Probably a somewhat valid problem, but my guess is that the panels will clear rather quickly when the sun comes out, unless it is bitterly cold, in which case the snow isn't going to stick much anyway. If you get a whack of heavy wet snow you might have a problem, but I suspect that is rare. My roof mount panels clear 6" of snow in a day or so once the sun comes out.

    The other idea is to put snow breaks like we do on steel roof between the panel rows, and at the bottom of the roof. Have to watch shading issues however.

    Tony
  • Ralph DayRalph Day Solar Expert Posts: 1,000 ✭✭✭✭
    Re: How to protect gutters from ice slides?

    Rather than brake the slide of snow why not run straps from the gutters to the roof and support them. If you slow or stop the slide then your panels will stay covered with snow and your production will be nil.

    I've seen these metal straps every 4 feet along gutters before. I have a steel roof and never had a problem with rip-offs, the snow gets a little layer of ice on the bottom and everything curls nicely over and past the gutters. As long as the gutters don't peek above the angle of the roof there shouldn't be a problem IMO.

    If anyone has experience with panels and roof snow shedding let's hear about it. My guess is that the shedding is a slow process off the panels (my arrays get the snow brushed off most of the time).

    Ralph
  • System2System2 Posts: 6,290 admin
    Re: How to protect gutters from ice slides?

    Take this with a grain of salt, as I am here on this forum representing a commercial entity.
    We have been seeing a fair amount of this situation on both residential and commercial projects. The issue is exactly what you have described; the composition shingle roofs generally do not shed snow, but when solar panels are mounted snow has the potential to release in monolithic slabs. The weather conditions necessary are not present with each snowfall, and as previous posters have said the snow will shed on its own in most cases without causing disruption.
    However, it is possible for the right amount of rain/snow mix to build up on the panels and remain there until it can become a problem. Not only do you lose the efficiency of the buried panels, but whatever or whoever is in the path of the snow is at risk. Gutters, walkways, landscaping, and vehicles have all been damaged by falling snow.
    The sister company of my employer, Alpine Snowguards, manufactures and distributes snow retention devices for a wide variety of roof types and applications, and among their products is a snow fence designed specifically for this situation. My personal recommendation to homeowners has been to invest in a low-cost solution to the problem, a foam snow rake. I have one for my car, and the same manufacturer also offers variations on their basic design. You can find them here: http://www.angelguardproducts.com/commercial/snopro
    (Mods please delete link if you feel it is inappropriate; I am not affiliated with Angel Guard)
    With this snow rake you can clear the panels relatively quickly without damaging the array or your gutters. Check out their close outs page for even better deals.

    The other option would be to mount our snow retention system below the panels. This snow guard will not shade the panels on its own, but is designed to hold the snow on the panels until weather conditions allow it to melt off. This option is more expensive up front, but is entirely passive. I tend to recommend this to customers with commercial projects who might not be able to reach their array with a snow rake, regardless of the length of the telescoping pole.

    I am happy to answer any questions anyone has in regards to either option. It is rare that I can bring any technical knowledge to the table on this forum as I am not an integrator, so today is a brave new day 8)

    [answering questions asked / posting relevant on-topic information is not considered spamming. Thank you for asking--Bill B. Moderator]
  • RegGuheertRegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    icarus wrote: »
    Probably a somewhat valid problem, but my guess is that the panels will clear rather quickly when the sun comes out, unless it is bitterly cold, in which case the snow isn't going to stick much anyway. If you get a whack of heavy wet snow you might have a problem, but I suspect that is rare. My roof mount panels clear 6" of snow in a day or so once the sun comes out.
    I've had thick layers of snow stick to my 60-degree-slope array, so I think it all depends on the conditions. I'm relatively sure there are conditions under which it is possible to get a heavy slide from a 40-degree solar panel.
    icarus wrote: »
    The other idea is to put snow breaks like we do on steel roof between the panel rows, and at the bottom of the roof. Have to watch shading issues however.
    That's a possible solution, but as you say, shading is a concern. I have no place to put a break on the garage, but there is some space below the array on the other roof. The question is how to catch a slide that is five inches above the roof...
    Ralph Day wrote: »
    Rather than brake the slide of snow why not run straps from the gutters to the roof and support them. If you slow or stop the slide then your panels will stay covered with snow and your production will be nil.
    Good idea! This might be the best approach.
    Ralph Day wrote: »
    I've seen these metal straps every 4 feet along gutters before. I have a steel roof and never had a problem with rip-offs, the snow gets a little layer of ice on the bottom and everything curls nicely over and past the gutters. As long as the gutters don't peek above the angle of the roof there shouldn't be a problem IMO.
    Agreed for the garage. As mentioned, I'm pretty sure there will be no issue with the garage, since the top of the panel will be a good five inches above the roof. I doubt any slides will hit that gutter. However, I can imagine an ice slide from the panels on the other roof curling down five inches over the 12-inch gap and impacting the gutters directly.
    Ralph Day wrote: »
    If anyone has experience with panels and roof snow shedding let's hear about it. My guess is that the shedding is a slow process off the panels (my arrays get the snow brushed off most of the time).
    I do, with my off-grid panels. However, they are at 60 degrees instead of 40, so they are not quite representative. Every snowfall is different, but there are sometimes slides. I expect 40 degrees should be worse for possibly generating large slides.
    Take this with a grain of salt, as I am here on this forum representing a commercial entity.
    We have been seeing a fair amount of this situation on both residential and commercial projects. The issue is exactly what you have described; the composition shingle roofs generally do not shed snow, but when solar panels are mounted snow has the potential to release in monolithic slabs. The weather conditions necessary are not present with each snowfall, and as previous posters have said the snow will shed on its own in most cases without causing disruption.
    However, it is possible for the right amount of rain/snow mix to build up on the panels and remain there until it can become a problem. Not only do you lose the efficiency of the buried panels, but whatever or whoever is in the path of the snow is at risk. Gutters, walkways, landscaping, and vehicles have all been damaged by falling snow.
    Uggh!! Here I am saying the gutters on the garage will be safe and not thinking about what will happen after the ice slides past the gutters! If we do not do anything to prevent slides, we will need to be careful where we park our vehicles in the wintertime!
    The sister company of my employer, Alpine Snowguards, manufactures and distributes snow retention devices for a wide variety of roof types and applications, and among their products is a snow fence designed specifically for this situation.
    Thanks! I looked at their website but I did not find the product to which you are referring. Perhaps their products are only for fancier houses than ours! :p I will probably give them a call and see what they might have to offer.
    My personal recommendation to homeowners has been to invest in a low-cost solution to the problem, a foam snow rake. I have one for my car, and the same manufacturer also offers variations on their basic design. You can find them here: http://www.angelguardproducts.com/commercial/snopro
    (Mods please delete link if you feel it is inappropriate; I am not affiliated with Angel Guard)
    With this snow rake you can clear the panels relatively quickly without damaging the array or your gutters. Check out their close outs page for even better deals.
    Our roof is the proper height and slope to be cleared using a snow rake, so I bought a telescoping snow rake *after* the big blizzards last winter. It is not foam, but it has foam rollers on it, so I think it might work on the panels.

    (On a related topic, I've been meaning to post a question about whether anyone has adapted a snow rake for cleaning solar panels.)
    The other option would be to mount our snow retention system below the panels. This snow guard will not shade the panels on its own, but is designed to hold the snow on the panels until weather conditions allow it to melt off. This option is more expensive up front, but is entirely passive. I tend to recommend this to customers with commercial projects who might not be able to reach their array with a snow rake, regardless of the length of the telescoping pole.

    I am happy to answer any questions anyone has in regards to either option. It is rare that I can bring any technical knowledge to the table on this forum as I am not an integrator, so today is a brave new day 8)
    It's not clear to me how the snow guard would work in our situation, but I am interested. I will research this in more detail. Thanks!
  • Ralph DayRalph Day Solar Expert Posts: 1,000 ✭✭✭✭
    Re: How to protect gutters from ice slides?

    I used to use a foam squeegee on my telescopic pole, but now use a broom head instead. The squeegee would get trashed by the panel mounting clips (between panels), but the brush is unaffected by them and cleans just as well.

    Could you find a shop broom head and mount it on your snow rake? Just don't want anything too heavy to hit the panels.

    Ralph
  • mr.radonmr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: How to protect gutters from ice slides?

    My sister still lives in CO. She has a long handle roof rake to clear snow off her panels.

    I myself a few years ago rehung my gutters with 3/8" shoulder bolts. I can do pull ups off the gutters now. Make it so the gutters can handle the snow shedding...
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: How to protect gutters from ice slides?

    Heat line makes a whole variety of heat tapes for melting ice dams, keeping gutters free running, and water lines:
    http://www.heatline.com/

    The are semi conductor technology so they only draw current only when needed. You could always wire a couple of strings of heat tape in strategic locations along the PV to either melt off troublesome snow, or to prevent cascades. Comes at some parasitic energy use, but for example, in a grid tie system, 2 kwh of heat tape freeing up a 2 kw array 1 hour earlier and your net cost of energy is $0. Even if you have to spend a few kwh over the course of the winter it might be worth the energy cost to save the damage to the gutters etc.

    Tony
  • RegGuheertRegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    icarus wrote: »
    The are semi conductor technology so they only draw current only when needed.
    How does it know when it is needed?
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: How to protect gutters from ice slides?
    RegGuheert wrote: »
    How does it know when it is needed?

    It's a conductive polymer, as it gets colder, the conducting particles get closer together and conduct, warming the heat cable up. as it warms, the particles move apart, and heat is reduced...
    Powerfab top of pole PV mount | 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 ,

  • RegGuheertRegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    mike90045 wrote: »
    It's a conductive polymer, as it gets colder, the conducting particles get closer together and conduct, warming the heat cable up. as it warms, the particles move apart, and heat is reduced...
    That sounds like it would use power whenever it is cold, not just when heat is needed to melt snow off the panels.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    RegGuheert wrote: »
    That sounds like it would use power whenever it is cold, not just when heat is needed to melt snow off the panels.

    that would be so if you leave it on all of the time so just unplug it when it's not needed.
  • RegGuheertRegGuheert Solar Expert Posts: 102 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    niel wrote: »
    that would be so if you leave it on all of the time so just unplug it when it's not needed.
    That would work! :D Thanks!
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    niel wrote: »
    that would be so if you leave it on all of the time so just unplug it when it's not needed.

    BINGO!

    Tony,,,,,
  • mr.radonmr.radon Solar Expert Posts: 158 ✭✭✭✭✭
    Re: How to protect gutters from ice slides?

    Well we had a cold snap here that has lasted five day and the panels have not cleared in five days. So today it took about 20 minutes but the most effective way to clear them was to just get on a ladder, grab squeegee on a 20' pole and rake the panels. You can see on my enphase chart what happened around 12 and then again 2PM (I went on a walk with the wife and dogs).
    I was considering heat tape or something else, but in the end I figure 45 panels would take me 10 minutes now that I know what works.
    Talked to my sister, she bought a roof rake with 20' handle. She does the same thing but from the ground. I found it easier to just walk the peak (I ice climb) and push it off. I would say to those without the right gear stay off a snowy roof unless you know what you are doing.

    One of the reasons I ended up on the roof was when the snow did slide, only the top 2' slid. The snow piled up in the gutters and blocked the rest from sliding off. When I pushed from the top the snow just piled up below the gutters. Not much remained in the gutters.
    So much snow came off my wife had to dig a path for the Subaru just to get out of the garage. She was surprised how big of a pile of snow that came down.
  • russruss Solar Expert Posts: 593 ✭✭
    Re: How to protect gutters from ice slides?

    @ mr.radon - At least you didn't make her go up on the roof! Andy Capp makes his wife do that part as well.:p
  • SCharlesSCharles Solar Expert Posts: 123 ✭✭
    Re: How to protect gutters from ice slides?

    For some yr., I had this snow problem. I rigged together a number of aluminum tent poles we just happened to have from an old tent and had to duct tape a final length of 3/4 inch wide strip of wood. Crude, but with a brush taped on the end, it worked for a decade. Then I had to reroof the house and I decided to relocate the panels to the hillside behind the house. I had to take the panels down anyway, a very obnoxious job, so took the time to pour concrete footings and etc.

    It is great. Now I walk behind the house, directly up to the panels, and simply sweep them off with a broom. Yes, I had to go up one gauge in the wiring and add some conduit to protect it all, but it is much nicer now.
  • System2System2 Posts: 6,290 admin
    Re: How to protect gutters from ice slides?

    I don't have a cost effective answer for this YET and I design in the NorthEast.

    I do want to warn you that a 10 pitch with what looks like 3 rows of modules is not good. When you get a good snow and the sun comes out you will probably see the lower half of the snow slide off. THEN when it warms up a bit more the top half will come down like an avalanche. Been there, seen that. It's something to see ONCE!!

    We installed EcoFasten SnowGuard between each row to stop the snow from sliding EVER. After installing these you can use a sponge pole to remove the snow if you want but you want to retain the snow slide.
  • bobdogbobdog Solar Expert Posts: 192 ✭✭
    Re: How to protect gutters from ice slides?
    mr.radon wrote: »
    My sister still lives in CO. She has a long handle roof rake to clear snow off her panels.

    I myself a few years ago rehung my gutters with 3/8" shoulder bolts. I can do pull ups off the gutters now. Make it so the gutters can handle the snow shedding...

    How do you secure the shoulder bolts? DO you screw them directly into the wood, or use a nut on the back side?
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,353 ✭✭✭✭✭
    Re: How to protect gutters from ice slides?

    I am not sure what "shoulder bolts" are but up here in the Sierra I use regular gutter bolts (the kind that screw in to the wood through a tube that is in the gutter) . The difference is most builders put them in on 30 inch centers. Install every 12 inches and make sure that the angle 'slide" of the roof is above the lip of the outside gutter wall.
    "we go where power lines don't" Sierra Nevada mountain area
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    mr.radon wrote: »
    Well we had a cold snap here that has lasted five day and the panels have not cleared in five days. So today it took about 20 minutes but the most effective way to clear them was to just get on a ladder, grab squeegee on a 20' pole and rake the panels.

    Makes me thankful I live further North where I can tilt my panels up vertically for Winter and forget about them till Spring.:D
  • solar_davesolar_dave Solar Expert Posts: 2,395 ✭✭✭✭
    Re: How to protect gutters from ice slides?
    Makes me thankful I live further North where I can tilt my panels up vertically for Winter and forget about them till Spring.:D

    Makes me thankful, there is no snow in my part of AZ! :D:D Garden hose for cleaning about once a month if no rain showers appear! :p:p
Sign In or Register to comment.