Thread: Snow guards on metal roof - good or bad?

These people lost their gutters last year, I presume by way of a dump of heavy snow. The house is only a couple of years young.

I told the potential buyers they could have the gutters replaced with stronger units, and that snow bars could be added to help stop the avalanches. Around here, the temps rise every couple of weeks and we get a big melt, so the snow doesn't stay long. The negative side of adding bars is that they trap leaves and debris. What do you guys in snow country suggest?

Would mounting the gutters a few inches lower help?

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Originally Posted by John Kogel

What do you guys in snow country suggest?

Not in snow country, but ... they need to add the snow bars/snow dogs/by various other names.

Would mounting the gutters a few inches lower help?

I doubt it, and then they would not do much good for rain as the roof runoff would likely overshoot the gutters running down and off the roof.

Also, that's one tall and unsupported vent/chimney.

Same with the overhead service mast.

Definetly in areas of heavy snow loads they are required.

I figure on any type of metal roof they are always a good idea.

Espacially for the people directly below.....lol

Lower the gutters?

Originally Posted by Jerry Peck

I doubt it, and then they would not do much good for rain as the roof runoff would likely overshoot the gutters running down and off the roof.

Right. Rain is #1 here. In some areas, snow will curl out over the eaves and snag on the gutters, but I think in this case, it can come down with a thud right on the lower gutter and then hit the walkway!

Originally Posted by Jerry Peck

Also, that's one tall and unsupported vent/chimney.

Same with the overhead service mast.

The chimney is clamped, with a spacer, to the edge of the dormer. Service mast is straight. OK, IMO.

Thanks, Joe. How good are these brackets? They can be attached with an adhesive. Do they stay put without screws? It appears as though the brackets can be used minus the crossbars? N.B.T. Building Products - Snow Guards for Metal Roofs - Snobar, Snojax, Snoblox, Icejax Canada

To be honest - seen them before - but never came across an installation.

Mechanically fastened metal ones are usually the best and most reliable.

The ones which look like long nails are good too.

I assume if they are tried and tested they should be good.

Defiantly Needed we call them avalanche guards .
Snow has a habit of leaving in one shot.
Saw a Mercedes damage about $30;000;00 hood fenders roof windshield.
Now how about if there was some children there, Closing the front door can cause it to move .
I write this up for all metal roofs.
Roy

Snow guards may be a problem if the roof structure is designed with slippery roof surface in mind. Adding snow guards does away with the advantage of slippery roof surface because the snow will build up more.
Aside from that; When recommending snow guards, recommend putting them over the overhang. In the event screws work loose due to the pressure of the snow load, there won't be a slow leak in the insulation.

They work, some larger buildings are designed with the snow shedding ability of the metal roof as far as snow load factors. A couple of years ago I saw a school with little drifts of the glue on snow blockers laying on the ground. I owned several metal buildings with huge south facing roofs with parking underneath. We ruined more than one car hood. Once that snow comes off you only have a short time to get it moved or you will spend the rest of the winter looking at ice mounds that can cause water invasion. Occasional replacement of gutters on those types of roofs is a given. Heat tapes are necessary in gutters on south facing roofs since often the roof will be warmer than ambient air (and the gutter) More often than not ice loads are the prime culprit in tearing down the gutters. having the gutters low enough that the snow goes over the top does work. In all but the heaviest rains the water drips off the roof edge rather than cascading off and if the rain is heavy enough for the cascade to start the odds are the gutter will not handle the water volume anyway.
I now looked closer at your pictures. Yes those gutters are way too high. But it appears that the dormer has no gutter and it is snow that has fallen off the dormer down 10 feet to the lower roof is the cause of the gutter being torn away. It appears the eaves are way too short to mount the gutters low enough. What is the spout appearing thing laying on the roof behind the stack? I might suggest putting gutter up on the dormer roof rather than down on that short lower roof.

Originally Posted by Roy Cooke sr

Defiantly Needed we call them avalanche guards .
Snow has a habit of leaving in one shot.
Saw a Mercedes damage about $30;000;00 hood fenders roof windshield.
Now how about if there was some children there, Closing the front door can cause it to move .
I write this up for all metal roofs.
Roy

LOL, when I lived in snow country (Lake Tahoe) we would call the people that parked that close to the building "flatlanders". There were even signs posted, warning of snow sliding off the roof and damaging vehicles. It was a picture of a Polar Bear knocked on his butt with birdies circling around. Too funny!

When I drove the County plow, it was usually a Mercedes sitting out in the street, blocking the plow so I couldn't clear the road. Although it was clearly marked to NOT do so. Have you ever tried to stop a huge, chained up Oshkosh all-wheel drive truck with 8 tons of sand in the back and a blade the size of an aircraft carrier deck on the front? On ice? Oops! Sorry 'bout that!
Dana

Snow guards , or fences may be required here due to the pitch. I noticed the upper roof had no gutters either,,where does that snow slide off to?

John,

I have used a product called snow jax. They can be put on with adhesive or screws. I use screws and silicone caulking. I wouldn't trust just adhesive. Caulk the bottom of the jax and then the perimeter once it's screwed down. This aids for potential leakage caused by the screw penetration. Leaves don't stick to these like the bars and they are clear plastic, so not too bad looking visibly.

Check out their site. They have various models based on the amount of snow and weight to hold back.

That aluminum gutter doesn't stand a chance with a snow slide. I have seen it take out a roof mast. That's was a good catch by Jerry. If it's not braced it can be taken out.

I'm sure that steep pitch on the roof doesn't help much either.

By the way, some engineers will take the load reduction for slippery surface roofing, if so I wouldn't recommend anything that would restrict the snow from sliding off. I had an architect take this reduction on the loading for steel trusses on a Nursing Home. The problem being, if someone down the road sticks these things on without knowing!

Snow guards require engineering per each roof''s design and are not a home owner or handyman install. Putting the guards on in the wrong pastern will actually increase the damage potential to the roof and pedestrians below. Proper guards are mechanically attached with hardware to the roof STRUCTURE and not just "stuck" on. Come on guys - snow is HEAVY. See installation of snow guards, how to install Bruin Metal Works snow guard products, recommended snowguard placement, roof snow dogs, metal roof snow guard products for a rough idea of what is required.

The damage to the gutters may be from snow falling from the upper roof surface. It may also be from ice buildup. On a resent inspection in Whistler, there was many locations where the ice had ripped the gutter right of the building and also damaged the edges of the metal roofing.

Hi all &

My own experience has been -- you EITHER use gutters (if you don't mind replacing 'em continually), OR use some form of properly-designed (as Sean has mentioned) snow-guards /hold-backs but not 'both' and also seriously restrict pedestrian and vehicular assess, below.

A former neighbour's house roof is metal without either gutters /hold-backs & I've observed some pretty interesting 'near-misses' over the years, when things warm-up & Mother Nature once again shows her stuff...


CHEERS !

Originally Posted by Sean Wiens

See installation of snow guards, how to install Bruin Metal Works snow guard products, recommended snowguard placement, roof snow dogs, metal roof snow guard products for a rough idea of what is required.

I'm sure the author of this article knows what he is talking about but saying that a 6/12 roof is 45 degrees could hurt his credibility. I agree with Sean that snow guards should not be installed unless the roof is designed for it. A roof covered with steel roofing could easily have been designed counting on the slippery roof surface.

That may be a good question for an engineer. But, from the installations that I have seen and inspected, if there are no snow jacks, there are no gutters. Based on the photos, it would appear that snow jacks should be installed. But it would be best to consult with an engineer - either from the roofing manufacturer or from a manufacturer of snow jacks. If the snow is damaging the gutters, it is just a matter of time before there is a human in the wrong place at the wrong time.

Thanks everybody and happy snow blowing!
For those who were wondering, yes the dormer has gutters, see 3rd pic, and yes the downspout has fallen off.
As far as designing for snow loads, that would be a concern on a large roof in snow country. For this particular house, less than 100 ft above sea level, I don't believe that is an issue, but it is a good point to bring up.
Re: The lack of a mast support - do I call for a repair before there is a sign of trouble?

Originally Posted by Glenn Duxbury

you EITHER use gutters (if you don't mind replacing 'em continually), OR use some form of properly-designed (as Sean has mentioned) snow-guards /hold-backs but not 'both'

Glenn, I don't see why they can't have gutters along with snow guards to hold the snow back. This isn't an alpine ski lodge, just a house that was probably designed for shingles. If the snow is held up on the dormer roof, it will melt away up there under normal conditions.

[quote=John Kogel;114424]
Re: The lack of a mast support - do I call for a repair before there is a sign of trouble?

I would at-least note it in your report. If they are going to install the snow jax, it would be a great time to brace the mast.