I am looking for guidance or recommendations on snow guard products. I have a carport with a standing seem metal roof. The roof slopes towards the driveway. A couple of times this winter a foot or so of snow slid off the roof, depositing roughly 10 cu. yds. of snow to be removed (36′ wide building). I see several styles including those that glue on and those that clamp to the seems. So I am looking for advice on which product to select. The roof is not really steep. I think it is 3/12 or 4/12.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
A pro painter evaluates a variety of drywall sanders and dust collection systems for quality of finish, user fatigue, and more.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Fine Homebuilding Magazine
Fine Home Building
Follow
-
Fine Homebuilding
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial Now -
GBA Prime
Get instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
- Home Group
- Antique Trader
- Arts & Crafts Homes
- Bank Note Reporter
- Cabin Life
- Cuisine at Home
- Fine Gardening
- Fine Woodworking
- Green Building Advisor
- Garden Gate
- Horticulture
- Keep Craft Alive
- Log Home Living
- Military Trader/Vehicles
- Numismatic News
- Numismaster
- Old Cars Weekly
- Old House Journal
- Period Homes
- Popular Woodworking
- Script
- ShopNotes
- Sports Collectors Digest
- Threads
- Timber Home Living
- Traditional Building
- Woodsmith
- World Coin News
- Writer's Digest
Replies
The glue on are less expensive than the clamp on. With the pitch as you describe, glue on is plenty strong enough. Follow the recommended pattern and apply in the recommended temperature range to a clean dry surface, and you'll be good to go.
John Svenson, builder, remodeler, NE Ohio
Ice guards must be very securely attached to the roof. I have never even heard of an ice guard that was glued down. Typically, they are screwed through the roofing with #14 screws or ¼" lags, and the screws must hit the roof framing, not just the sheathing.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
I don't think he'll want to screw thru his metal roof - there are lots of other ways to fasten them.
Walter, we screw thru metal roofing all the time to install these. Put a good dab of butyl rubber under the foot of the ice barrier and run the lag screw through that and into the framing with an impact gun. Those ice barriers have to hold back several tons of ice and snow; no glued on gizmo could possibly hold.
I've even seen ice guards ripped off when they were screwed on but with small screws just run into the plywood.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I know what you're saying. But I bet the roofs you're talking about are steeper , have longer rafters and much more annual snowfall .
I asked the OP where he was located in a prior post , 'cause that could be a factor.
Did you see Grants thread " copper roof " the other day. He's using individual clamp to the seam guards to limit snow slides , but he's in a more mild snow area than you and I.
Not trying to argue , but in some area the glued on ones might work.
Where Grant is, I'm kinda surprised he needs ice guards at all. But whadda I no....
Actually, the lower-slope roofs--3/12 to about 7/12-- are the most dangerous ones. Steep pitches roofed with metal have a greater ability to shed the snow as it falls, and of course they form much smaller ice dams at the eaves.
I wish I had a pic of the ice overhang that builds up on place next door to mine in the spring. He's got a 4/12 roof with screw-down prefab metal, and no insulation or venting in the roof. In good winters, the ice dams get to be about 18" thick. He didn't have ice guards until a few years ago, and as the weather warmed up the ice dam would slide sloooooowly out off the roof over the course of a couple of weeks, with the snow up-slope forming new ice behind the old until the ice 'roof' extended about 5-6' over the side yard. When that finally broke off and hit the ground, it felt like a solid 4.5 on the Ricter scale....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Glue down snow guards are very common here in Ohio. Just because you never heard of them doesn't mean they are no good.John Svenson, builder, remodeler, NE Ohio
Glue down snow guards are very common here in Ohio.
So are winters with 6" or less of snow accumulation on roofs. Here, the first friggin' spring thaw has arrived too bloody early, and most roofs still have three feet up there. Wet and heavy, too. No glue is gonna hold back that load if starts sliding....
I don't remember where the OP is from; methinks it was the great NorthWet or someplace? What snow they get is usually pretty heavy-duty stuff....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
You don't know much about Northeast Ohio.And by your own admission nothing about glue down snow guards.Some parts of the Northwest get huge amounts of snow. Some parts get very little snow.Kind of like Ohio.John Svenson, builder, remodeler, NE Ohio
Hey, Svenny--I don't know who pissed in yer Pepsi, but it wasn't me. I'm not looking to pick a fight with you over this.
Just so you know--I thought you did, actually--I lived just south of Cleveland from 1964 to 1970. Yes, I saw some moderate-sized snowfalls, but I never saw any accumulation worth worrying about.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Edited 3/10/2009 8:43 pm ET by Dinosaur
Nobody pissed in my Pepsi.But the OP has a 4/12 roof with an 11 foot run, and you have made it a point several times to dismiss glue-on snow guards as totally inadequate, urging the use of snow guards that require screwing or lagging through the panel. Not just into the sheathing, but all the way through to the rafters. On a 4/12 with an 11 foot run??I simply pointed out that glue-on guards are worth considering, you are the one that stated that glue isn't up to the task.On your other point of Ohio snowfall. I've spent several winters shoveling 2-4 feet of snow off roofs in Geauga and Lake counties. Have you forgotten about the snow belt?John Svenson, builder, remodeler, NE Ohio
For 36 feet of roof width by 11 feet of rafter length (the OP's roof), by 4 feet of depth (your figure, not mine), you're talking about 1,584 cubic feet of snow.
Dry, packed powder snow weighs about 14-19 pounds per cu. ft.
Heavy, wet, snow of the sort you get up near the Lake (and out in the GNW), weighs between 40 and 50 pounds per cu. ft. Ice dams can weigh up to 60 lb./cu.ft.
So. 50 pounds times 1,584 cu. ft. = seventy-nine thousand two hundred pounds...or just a tad under 40 tons.
You're entitled to think glue can hold that back; I'm entitled to think it can't.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
1.) I never said glue down snow guards were the best choice for every situation.
For some reason, you seem to think I did.
.
.
.2.) You out of hand disregarded any consideration the OP had for glue downs because in your exact words: "I have never even heard of an ice guard that was glued down. Typically, they are screwed through the roofing with #14 screws or ¼" lags, and the screws must hit the roof framing, not just the sheathing." So you completely reject the use of a product that you never heard of! I won't comment further on your ridiculous statement that snow guards must be screwed or lagged to the roof framing. Rafters would have to be layed out to coincide with the specified pattern, usually 3-4 per foot (sometimes more).You see when I install these, I am usually working from a pattern specified by the architect or the snow guard company where local conditions are factored in. I have run as many as 6 per foot.
.
.
.3. Where did I say the OP's snow load was 4 feet??? That's right I didn't. I said I have shoveled 4 feet of snow off roofs in OHIO-where BTW you said:
"Just so you know--I thought you did, actually--I lived just south of Cleveland from 1964 to 1970. Yes, I saw some moderate-sized snowfalls, but I never saw any accumulation worth worrying about."
.
.
.4. But then you try to make your point with a bunch of bogus math. You calculated the TOTAL WEIGHT of 4 feet of wet snow on a roof 11 ft x 36 ft. The total weight is pertinent to the building's structure (rafters, trusses, walls, headers etc.) But it means nothing to the the snow guards that are holding back the force of the snow load along the roof line.
The roof is a simple inclined plane, and if you ignore friction (consider it zero) the force exerted on the snow guards is expressed as: WEIGHT x sin (of the roof pitch) = force on the snow guards.
A 4/12 roof is approx. 18 degrees, the sin of which is .309 So, using your figure of 79,200 lbs:
79,200 lbs. x .309 = 24,472 lbs of force on the ice guards. An impressive sounding figure. Until you realize that at 36 ft. you would have 108 pads at 3/foot or 144 at 4/foot. This results in 24,472 lbs / 108 = 226.6 lbs per pad. Or 169.9 lbs per pad at 4 pads per foot. Each pad is 18 sq. in. So, 226.6lbs/18 = 12.5 lbs/sq.in
.
.
.5. The glue has to be capable of holding back 12.5 lbs/sq.in Doesn't sound quite as intimidating as 40 Tons does it. But you're certainly entitled to think it does.
John Svenson, builder, remodeler, NE Ohio
So ... go forth and sin no more!
Jeff ;o)
Usually I engage in cosin. Oops. :-}John Svenson, builder, remodeler, NE Ohio
This thread may now go off on a tangent!John Svenson, builder, remodeler, NE Ohio
It is arcing off the path.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Lightning rod guys? I thought that went out with Uncle Herbs Snake Oil. where are they installing these?
fairly common here in Ky.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
It's all a matter of degrees.John Svenson, builder, remodeler, NE Ohio
Man you musta added 100 proof to that Pepsi now !!!
I'm the OP, and am an engineer, so I like the math here. For what it's worth, the most snow I have seen on my roof at any one time is 3 feet. The snow can get heavy here in the great NW, but usually when that much snow comes it's quiet cold so the snow tends towards the lighter side.
The thing I don' t like about the bonded ones is that from what I can tell they are supposed to be applied in a staggered pattern, which I think will look lousy. My house, shop, and carport are aligned in an L configuration, so the snow guards would be visible off to one side as you drive up to the house.
Here's an illustration of one type of modular guard I'm familiar with. With your 3' snowpack and your concern about the look from ground level, something like this would probably be a good choice.
View Image
Here's a link to the manufacturer's website: http://www.renodirect.ca/Pages/GardeNeige_new.asp
You probably only need the one- or two-hole plates. We don't install three-bar guards except on roofs with particularly long slopes or steep pitches.
Failing that, get in touch with a local wrought-iron fabricator and have him weld up an 8"-high, two-row barrier for you out of ¼x¼ stock. My local guy makes them in 8-foot sections with feet spaced either 16" or 24" O.C. (depending on the roof framing) and one 20"-long angled strut (going up the roof) for every second set of feet.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Telling us where you live and what style of metal the roof is will help folks here give you better advice.
Is it a true standing seam roof ? How long a rafter do you have ?
Are you in a Northern State ?
Am in Washington State, in the Cascade mountains about 15 miles from the entrance to Mt. Rainier National Park. Elevation is about 1850'. The carport is basically a pole building with 2 sides.
Bill,
Try this site for starters.
http://www.alpinesnowguards.com/standing-seam-snowguards.php
Oh yeah, the roofing is Champion SNAP-LOC. link is below.
http://www.championmetal.com/Default.aspx?Redir=ProductTypePage&id=7&Type=Snap-Loc
I'd call the people at Alpine Snow Guards and ask their opinion.
Snow retention is their business and could give you the best answer for your location , roof construction , etc.
I'm sure they'll know if the clamp on guards they can provide will work with your snap lock roof panels.
Look for the 800 number on their site.
along the same lines, we had a job where we just installed a standing seam copper roof and the Lightning rods guys cmae to install thier junk. We made it very clear, NO HOLES in the copper,PERIOD.
After awhile we wound up going back and upon checking thier work, I found empty tubes of liquid nails, and even a caulk gun with a tube still in it. It was a 10 or 12/12 and what a pita to have to go back up, w/out our set up, and reattach the air terminals and wire guides. Wound up getting offf as much of the glue as we could and soldering them on.
One of them days where ya climb up the roof with vice grips in each hand, attach one, pull up, attach the next pull up, hand over hand to the ridge and straddle that while ya get out the torch, flux and solder.
The clamp ons I have installed, held great, even stood on them while working, like a roof jack.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Thats the beauty of the clamp on ones. Staging that you can even set a ladder against for easy access up to the ridge.
Clamp-ons are definitely the best way to go. Snow rails offer even more protection. Very pricey however.The glue on systems I've used have a proprietary glue. Can't imagine anyone using Liquid Nails or PL on them-what a mess that would be.As far as copper goes, I don't even know if the plastic & glue is compatible with copper. I've only used them on painted or Kynar systems. I would never use plastic with a copper roof. If the customer appreciates copper, why would they want to put something plastic on it?John Svenson, builder, remodeler, NE Ohio
I never saw a plastic sno-gard, all I've installed were cast brass.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
These are the ones I have used:<A REF="http://www.alpinesnowguards.com/30cl-pad-snow-guard.php">Plastic Snow Guards</A>They're not for every application, but are fairly common around here.John Svenson, builder, remodeler, NE Ohio
http://snoblox-snojax.com/metal-roof-snow-guard/snow-guards-4.html
View Image
Used on two projects - would not use on a traditional roof (I like the MJ Mullane guards ... now owned by Berger Bros.
Mullane - http://www.bronzeguard.com/default.asp?LINKNAME=BRONZEGUARD
View Image
Jeff
Edited 3/15/2009 11:05 pm ET by Jeff_Clarke
Today I took out my SmartLevel and measured the angle of the roof (18.5 deg.), which makes it a 4/12 roof. The rafter length is about 11'.
I like the idea of the ones that clamp on to the seams. Here in the great NW the weather limits installation of the bonded ones to about July 15 - Sept 15, especially since the instructions say you need a good week of warm dry weather to let the adhesive cure completely. To me it looks like there are 2 types of clamp on snow guards. One type I will call a "free standing", with a blade that sticks up to grab the snow. The other type looks like you run a pipe through the clamps clear across the roof. Any thoughts on those choosing between the two? It seems to me the pipe type might be more aesthetically pleasing because the line is perpendicular to the roof seams, where it appears the other ones are installed in a stagger pattern.
I think the pipe running thru the clamps , bolted to the seams will both work and look the best.
Good luck with your project.
Walter
The snow pipes or rails are the "Cadillac" systems. You can install single or double rails - whatever your budget allows. I haven't run into too many customers willing to spend that kind of money-most go with clamp-on or adhesive pads. The "blade" style you describe has a channel you can slide a strip of metal color matched for your roof so the "blade" blends in. They come in various widths up to 3" I believe. You need to provide the metal insert to match your roof.
BTW-you only need 3 days of 40 degrees or above for installation, wet or dry. You just need the roof to be dry when you install. It can get wet after they are installed with no ill effects. It takes 7-14 days for the adhesive to cure to full strength. Wetness doesn't prevent curing. I have used a hair dryer to dry the panel for gluing.John Svenson, builder, remodeler, NE Ohio
thanks for all the advice. now I just need to print out this thread....
What Dino said. We (British Columbia) put them through steel roofs all the time, lagged securely into the framing. We use a putty compound that comes in tear-off strips. It seals between the guard mount and roofing. It lasts forever; I've never heard of leaks.
Roofing guys should know about this stuff, if not let me know and I'll inquire.
Scott.
Thanks, i will check into this. In another posting I just made I mentioned my lack of enthusism for bonded ones.
I hope this article helps: https://snoblox-snojax.com/blog/how-to-choose-the-best-snow-roof-guard-system-for-your-roof/