Sheet Metal Roofs & Snow Damage Page

Updated 6/20

A damaged gutter from icy snow sliding off a pole barn roof January of 2004

We normally do not get much snow here in the NW.  Also, the conditions were such that the top layer melted slightly during the day, and froze hard at night, to the point where the next morning that you could walk on top of the snow without leaving a mark, because of the top 1/2" layer of ice that formed.  It caused a unique situation, especially for metal roofs, where snow is especially prone to slide off even low slope roofs like this one, with only a 4/12 pitch to it.

I had not done much work replacing gutters on houses with metal roofs, so I had not run into this issue in the past, other than putting a lot of pressure on the leaf screen covers and having mangled screens.  This is just one of the issues with metal roofs, but there are many reasons that metal roofs are crap and may cause serious problems.   See our Roofing web page to learn more why metal roofs are a very poor choice for a roof cover of any structure.

I did not recall the details of this installation until I got out to their place to see it first hand.  As luck would have it, this was the only structure I had ever used a set of new nylon hidden hangers that a pushy salesman gave to me for free, and kept pestering me for months to them try-out.  I told him I felt they were no good for gutters, since even though they may be made of a high quality nylon plastic I believed the sun exposure would cause them to become brittle and fail long before the gutter it's self.. I only used them on their shop, and used the aluminum hangers on their house. the gutters on the house were fine, but they were not under a metal roof.

I did not like them after using them either, so I had decided to not purchase any. Thank my lucky stars this was the only time I did try them out!  Only about 3 or 4 of the 42 nylon hidden hanger had not broken.  They had not even been up there long enough for the sun to break down the plasticizers in the nylon, but it showed that in cold weather they were too brittle and snapped.  They had clearly proven to be worthless, and I would have had a great deal more warranty work to deal with if I had decided to use these nylon hangers, instead of the heavy-duty aluminum hidden hangers I have used since 1992.

This photo is the same gutter after the snow curl had broken off and fallen to the ground.  This better shows the screens all bent up and hanging off.

I had since found an even better source for stronger aluminum hidden hangers that are called 'Monster Hangers'. I have to order from a supplier in Connecticut, since the local suppliers are not willing to stock them due to such a sparce demand for better parts by the other Cutter Contractors in this area.

As you can see here; 45 screws out of the 46 held-up to hold in the back of the gutter just fine.  But it was the hidden hangers that under that force failed to hold the outer lip of the gutter in place.  The screens also were damaged as you can see.  Fortunately it did not damage the gutter bad enough that I had to replace it. I just replaced all these hangers with the aluminum type.

Another way this damage may have been avoided is if I were able to mount the gutter below the roof line, but in this case I needed to install the gutters to be sealed up under the drip-edge flashing, and I was subject to the restricted height of the small 2x4 rafters I  had to mount the gutters on. The only way to improve this situation would be to cut the rafter tails back an inch and mount a 1x6 fascia board over them before the gutter is installed lower. Some additional flashing would need to be added to close the gap between the roof line and the top edge of the gutter.

As to warranty, there was no question in my mind as to this being a warranty issue for me to fix.  Even if at the time of installation I had informed the client that I was trying-out an experimental product on their barn, I would have still felt responsible.  After replacing all those crappy plastic hidden hangers with the aluminum Monster Hangers that I now use, I also cleaned out the gutters and replaced all the screens with the new stronger black screens I had switched over to.  The new screens are wider: 4' wide, instead of only 3'.  They also have 3 clips per screen, instead on just 2. I only charged half price for this screen upgrade, accepting our portion of the responsibility.  The client was happy to pay that small amount for this repair.  I was very fortunate that the gutters were not damaged beyond repair, or I would have needed to replace them as well.

There are several companies that make devices to prevent these sort of snow loads from sliding off the roof, like Snow Gems for instance.  These require puncturing more holes in the roof cover and will cause a blockage for debris during the rest of the year, so I do not recommend them.  They also have a problem with hiding the fastener to secure them in place. Some are made with a double-sided stick-on tape so there is no fastener, but that limits it to only a new installation roofs and has a limited life, as well as not attached well enough to stop a heavy snow that would pose a real problem. Some add a pipe or bar across the roof's standing seams. All of these options add visual pollution to the look of a roof.

Mounting the gutter lower to the roof-line should solve this issue for low slope roofs, but with steep roofs it is often not an option to be able to mount the gutter low enough to avoid this issue.  The gutter would have to be lowered as much as a full foot down to avoid the snow slide on some very steep roofs.  Most houses are not designed with a tall fascia board to allow for such a low placement, and there would be nothing there to attach the gutter to.  Not to mention how terrible it would look.

Below is the correspondence before we had a chance to see what happened first-hand.  With the assumption I had installed those gutters the same way I always had. I was seeking a reasonable solution that will also prevent this from re-occurring in the future:

Greetings GLL,

At 0455 PM 1/11/2004, you wrote

>The 'curl' was bizarre...<

WOW! that is incredible! You are right, I have not seem anything quite like that. I am not sure what to make of this as a warranty issue. Looking at the digital photos, it looks as if the gutter is damaged as well. It seems the hidden hangers remained screwed in, but the hidden hangers were bent out form the outer lip of the gutter. Leave it to you to come up with such a wild issue. <LOL>

>Most if not all the gutter screens are now destroyed ...<

Honestly, I do not know what else I could do, with the building the way it is, to mount a gutter any better than I already did. They do not sell parts better than what I used, and I could not install more hidden hangers than one per rafter tail, like I already did. With the 2x4 rafter tails I see in the photos, I could not even drop the gutter lower than it is.

It is quite clear that we do have a serious dilemma here, and I am happy to do what I can to help brainstorm this issue, to come up with a trouble free solution.

The only other option I can think of would be pretty labor intensive, but you are free to offer to do any part of this work to minimize the cost of having me do it all

(a) We would need to cut each rafter tail off vertically 1.5" to 2" back, in preparation to mount a large fascia board across those rafter tails.

(b) Then mount a 2x6 or 2x8 fascia board with screws that go deep into the rafter tails.

(c) Make a new gutter with the hidden hangers placed each foot (4 times the building code, instead of only twice)

(d) Then I would mount the new gutter lower (as I suggested on the phone)

>Let me know if you can come by in February ...<

That should not be a problem. I only have a couple jobs on my schedule.

Date 27 July 04

Although I am not the expert, the gutters look fine. The interior brackets have sagged in a couple of areas, but it appears that they can be bent back to their proper angle with a series of local, light, upward force.

Unless my eyes are tricking me, most of the lengths are level, and the front end has sprung back as well, just not all the way - it's about a 25-degree twist. Things appear level at the downspouts, though. Same deal on the backside of the shop.

SO, come on out and I'll write you a check for the simple re-screening.

- GLL