snow guards for metal roof

[left field]

I'm getting conflicting info. Does anyone have experience with these?

I have a shed roof on my cabin - 36' feet from peak to bottom. About 24' from the peak is a metal chimney with two supports rods. There is a seam across the roof about 4' above the chimney. Last year, the snow ripped out one of the supports and damaged the chimney, so I need to protect it. Not concerned about snow falling below as it isn't a walkway. 

Three pieces of advice:

1. two rows of staggered poly guards above the chimney and support (roofer advice)
2. three rows of staggered poly guards across the span of the roof to ensure that the snow load doesn't "hinge" at the last guard and take out the support (supplier advice)
3. rail across the bottom of the roof (below the chimney) to keep all the snow on the roof until it melts (chimney installer advice)

Any thoughts?

[blaine35]

With the location of the chimney and supports I would go with a minimum of two rails. One located below the chimney across the roof and one 10 -12' down from the top. The rails are cheaper and faster to install than poly guards if you get the ones that are bent metal like this >>>> 

[left field]

@blaine35

Do you have a source for rails? Can't seem to find any locally. Everyone is selling the poly guards. Is the install just screws w/gaskets or silicon as well?

Thanks.

[blaine35]

Many building supply companies don't know they are available and also they can't stock some of every color of roofing so they all sell the poly guards. If they sell Fabral, ABC or the other main metal roofing manufacturers they can order them to match the color of your roof. Installation is as easy as two screws per rib with a little silicone. One screw is shorter and called a stitch screw and holds the bar to the rib only and one is longer and goes into the framing. Are you anywhere near a Curtis Lumber?

[left field]

I am near a Curtis, but I didn't see it on their site. I will be up there on Thursday so will check it out then.

Sorry to be daft, but are you suggesting two full runs across the roof? One 12" off the bottom of the roof (split in two as there is an small jut out on the left of the building) and the other above the chimney at the 12' mark above the seam? Basically holding all the snow on the roof? 

Not sure if you can see, but this is a standard profile and not standing seam.

Thanks.

[blaine35]

Curtis Lumber sells Fabral and ABC among others. Here is a link to the Fabral "Blue Book" >>>  https://fabral.com/media/1229/pf-blue-book-7-15.pdf the Snow bars are on page 17 if they don't know what they are. Item SB for roofs with plywood sheathing and item SB1 for roofs with purlins. They can order them in any color and amount.  I suggest doing runs across the whole roof but will the roof support the snow load that is now going to be retained on the roof? A lot of factors to consider, snow load in the area where the camp is, roof structural framing and condition. If you are confident that the roof is structurally sound I would do a minimum of two rows for 36' of roof length but that is a minimum 3 rows would be ideal. Here is a link to installation for the poly guards >>>> https://fabral.com/media/1991/tb722snowguards1.pdf basically just substitute the snow bars for where the poly guards are located for your size roof.  Better order soon, snow is on the way.

[Hunter1]

I had the same problem I installed a cricket above the chimney an removed the two rods no more problems handle a 48 in snow fall last year

[left field]

Thanks @blaine35 I'll check it out.

@Hunter1 The chimney installer mentioned a cricket after he did the repair. Why he didn't suggest it when he first installed the chimney, I'll never know.

[Dom]

13 minutes ago, left field said:

Thanks @blaine35 I'll check it out.

@Hunter1 The chimney installer mentioned a cricket after he did the repair. Why he didn't suggest it when he first installed the chimney, I'll never know.

Crickets are for chimneys not stove/furnace pipe.I have made ice snow breaks for my roof if  you know someone that has brake for bending metal they can make some for you.

[blaine35]

I was going to mention building a curb(a box) around the chimney and a cricket above but thought the snow bars were more of a do it yourself type project. Any time a metal roof is penetrated you need to take care to flash and seal properly. This would hold less snow on the roof though and get rid of the two supports. Cost would be about the same.