Snow Guards

[Spectrum1c]

What is everyone's experience with snow guards or solar guards (whatever you call what is put on your roof to prevent falling ice)?

I recently had solar installed on my house, and have a fairly large installation (58 250w panels) We had some crazy weather last week in NJ with a lot of ice accumulation, and basically had sudden avalanches off my fairly-high roof of very heavy ice/snow that cause a bunch of damage in front of (basically all the shrubs, bushes, trees landscaped around my porch) and behind (a bunch of patio furniture was destroyed) my house. From a safety standpoint, I'm worried someone (like my 5 and 3 year-olds, or even a mailman or someone walking up to my house) could get seriously hurt or worse. And then there is future damage to consider, especially as my homeowner's insurance have told me they don't cover personal property from falling ice. There was just an incredible amount of weight that came off my roof all at once, and not something I ever even considered when deciding to go solar (the fact that my normal roof was going to become closer to a metal roof that stuff slides off much easier).

Is there a product out there that really works well, and at the same time doesn't look terrible? My understanding from what my original installer has been telling me is that this ice situation is very rare, and normal snow is not going to be an issue even without solar snow guards (and in truth, we have had 5 or 6 snow falls already this year and only the 1 ice-storm situation caused damage). They mentioned that these guards will do nothing the 98% of the time there is no snow, and then 95% of the time there is normal snow will keep it trapped on my roof longer and hurt production. However, even if it what happened last week is just a .01% occurrence, I feel like i need to deal with the safety issue. With the amount of weight, I'd assume they would have to attach these guards into the frame the panels all sit on (as anything else like my gutters would just be ripped off my house). Optimally, it would be great if these things were pretty much unnoticeable, would stop large ice avalanches off my roof, but would not impeded regular snow from falling (or shade the panels in any way). Not sure how realistic that is.

Appreciate any thoughts anyone has on this. Thank you.

I'm in a similar situation. What was your final decision.

Anyone else have other recommendations?

[SnowGuards]

Roof Things LLC carries a variety of snow guards/ snow stops that could be helpful.

Admin note, hi snowguards, no advertising links for newbies please.

[Mb190e]

Are you speculating at the end that if you had not snow blown the deck the top section would not have slid so soon?

No, we were forecasted to get 2 feet of snow I had the camera out there rolling all day waiting for it to slide off. I was recharging the battery on the camera when the rest of it slid down.

[inetdog]

Yeah I'm worried about it falling on the dogs and the kids. So I take a proactive approach and try to get it off of there before it slides off unexpectedly on its own. Plus the quicker I get it off the more power I can make. Last thing I want to do is trap it up on the roof.

Nice video with good production values.

I like the way raking a small section can trigger a large wide area slide. If you had projections that increased surface friction that would not have been nearly as dramatic.

Are you speculating at the end that if you had not snow blown the deck the top section would not have slid so soon?

[Mb190e]

Yeah I'm worried about it falling on the dogs and the kids. So I take a proactive approach and try to get it off of there before it slides off unexpectedly on its own. Plus the quicker I get it off the more power I can make. Last thing I want to do is trap it up on the roof.

[peakbagger]

The other thing to note is if you can access the panels with a rake, if its raked right after a storm, the snow is no where near as dangerous as if the you wait a few days or let it just slide on its own.

[pleppik]

One thing I have heard from multiple folks is the salespeople for the firms that install solar in snow zones just don't talk about this and let the owner have a surprise the first winter.

One of the installers who bid on my system actually did mention this hazard. He didn't offer any particular solution, though, other than "watch out."

The challenge is that you do want the solar panels to shed snow in the winter, so they can produce power. But you want them to do it in a way that won't hurt anyone or anything.

The ideal solution is probably to arrange the roof and landscaping in such a way that the "dump zone" is away from sidewalks and driveways. When there's snow on the ground people aren't likely to be walking anywhere that's not a cleared path, so piles of snow sliding onto a dead perennial garden is likely to be safe.

[peakbagger]

I added a relatively shallow roof mount array a couple of years ago and snow accumulation and subsequent slides have been interesting.

Some observations are:
-The Iron Ridge panel clips that have a threaded stud with a nylock nut projecting about the top of the array are enough to catch a snow slide and the stagger the slides. I routinely see one vertical section (2 portrait panels) let loose while the adjoining others hold steady. Usually the other sections start falling over the next few hours.

-The snow gets caught on the horizontal array frame between vertical panels

- Snow buildup on the exposes shingles at the base of the array makes a big difference on when the snow slides. My theory is that the roofing is relatively dark and absorbs heat. If I clean off this area in the AM after a storm with roof rake, the snow slides off faster.

-Once the snow gets sliding, it builds momentum and I don't expect any clips will stop it.

The state of VT went "wild" about 20 years ago for metal roofs. Lots of new architectural gems that usually were two or three story barn like structures with 12/12 pitched roofs where built for commercial use. There were many injuries and some deaths due to snow slides. There is also a population of older slate roofs in New England and they have similar snow sliding issues. A lot of slate roof fixes were applied to steel roofs. Many of the slate fixes are installing essentially a guard rail at the base of the roof up a bit from the gutters. Theses system are not particularly attractive and also can contribute to ice damming and huge icicles plus it makes the roofs impossible to rake. Most of the steel roof companies went to snow clips that attach to the standing seams. They work but again they make the roof darn near impossible to rake. Many roofers but in multiple courses of clips, they generally alternate them every other row with a 2 foot spacing. They are not readily obtrusive from a distance (far less than the guardrails). Even with these fixes, many firms post there sidewalks about falling ice as if the conditions are right in the spring the entire mass of snow can still break apart and come down with a rumble.

I just encourage my snow to slide by raking the shingles at the base of the panels. If I were to try to retain the snow, I would install horizontal clips that project up at the horizontal seams between panels. These wouldn't have to be real high, I expect 1/2 to 3/4 of an inch which wouldn't shade a panel. I think a sheet metal worker could probably make then up with flange at the base and then a stake that slides down between the panels and some sort of projection that springs out and catches the bottom of the array frame. (there is probably free business idea for someone to mass produce these).

One thing I have heard from multiple folks is the salespeople for the firms that install solar in snow zones just don't talk about this and let the owner have a surprise the first winter.

[bcroe]

Sliding Snow Hazard

How about, mount your panels in landscape orientation, with half a foot between
each tier to snag snow? Put a sturdy awning over entrance ways (used here)?


I think I will add this to my list of ground mount advantages.
Bruce Roe

[Alan P]

Protecting the walk makes sense but nothing more.

This is my first post, hopefully I get this right...anyway, I also live in New England and so experience the snow/ice/slush avalanches regularly. The risk of serious injury definitely exists which is what brought me here searching for solutions. So far we've been lucky though our dog, who waits by the back door, had some close calls at first (I'm very careful now about letting her out after any significant snowfall). The other problem, not life threatening but still a problem, is that all the snow from that side of the roof collects at the base of the house along the foundation rather than melting and draining off through the gutter system. So that all has to be shovelled away after each storm, otherwise we'd certainly have a wet basement to deal with in the spring. I haven't found a good solution yet but I'm sure there are some good ideas to be found out there.

[russ]

Protecting the walk makes sense but nothing more.

[Mark_C]

The issue with snow on solar panels, unlike asphalt shingles, is that the glass surface of the panels can accumulate a foot or more of snow that can very suddenly break free in its entirety because of the slippery surface, causing an avalanche. I have a fairly large 40 panel array, and the snow load on that size array can be over 10,000 lbs. The panels are designed to handle that weight, but if it all releases at once, you're talking about the potential for some serious damage or injury down below. This was my first winter with the solar panels, living in New England, and I had several days (usually the day after a big storm) when I heard a loud low rumbling noise that sounded like a big plow going right next to my house, but I quickly realized (by the 4+ foot drifts in front of the house and the snow-free panels) that it was snow from the roof that had all released at once. Seeing and hearing this happen, it's easy to become concerned about damage or injury as the OP says. A section of the roof is directly over my front door, so it's definitely not the best way to be greeting the mailman. We're thinking about snow guards and/or a roof extension over the front door to help reduce the risk. Would love to hear from people who have installed the snow guards and what their experience has been. Obviously this will reduce the production of the panels during the winter months, but the production is significantly lower anyway, and the trade-off for the added safety seems well worth it to me.

[J.P.M.]

The only practical problem is if it previously slid off in small increments but after the solar PV install it started coming off in much larger increments.
I can visualize a much larger snow dump from a smooth glass panel as melting occurs than from a textured shingle roof.
Whether or not that is a problem may depend on just who is standing under it at the time.
(Cross reference George Washington/Indian Chief/Outhouse joke.)

Also the differences between snow falling off and ice falling off can be considerable.

Maybe something similar to the way ice dams on roof eves and overhangs form over poorly insulated spaces ? Just a SWAG.

[inetdog]

Pray tell what is wrong with the snow sliding off - just like it always has done?

The only practical problem is if it previously slid off in small increments but after the solar PV install it started coming off in much larger increments.
I can visualize a much larger snow dump from a smooth glass panel as melting occurs than from a textured shingle roof.
Whether or not that is a problem may depend on just who is standing under it at the time.
(Cross reference George Washington/Indian Chief/Outhouse joke.)

Also the differences between snow falling off and ice falling off can be considerable.

[russ]

Pray tell what is wrong with the snow sliding off - just like it always has done?