Homemade "snow dam" for roof?

[Mamba]

An unusual snow load this year took out the vent pipe off my steep metal roof. Since we rarely get big snow and the roof normally sheds it quickly, I hadn't seriously considered a snow dam or similar device until now.

I checked at the local building supply store, and the "dam" product they sell appears to be a piece of heavy flashing with a 90 angle to form a ledge about 2" high. Not very impressive, and no profile to match that of my roof.

With a vent pipe extending 18" above the roof line, I would expect the dam to stop the bottom 2" or so, and potentially the upper layers could slide over it and take the pipe out again. The snow would have about 20' of roof to gain momentum.

So I am considering an alternate device, something like a few very stout "pegs" in an inverted Vee shape above the vent pipe. My theory is that snow or ice could come down but then be split up or diverted by the set of pegs. They could be 6" or so high, perhaps galvanized lag bolts with a short length of 3/4" pipe around them. Perhaps a total length of 6" or so. I even have paint to match my metal roof color!

Looking for opinions on whether this might/not work.

Cheers

[Reinhard]

"Mamba" wrote in news: [e-mail]:

You could brace the vent pipe with a support wire to one strong bracket. The wire would both support the pipe so it could take the hit and break the snow into two parts which would flow around the pipe and reduce the total load. Make the wire 10 ft long or more so the slope of the wire causes any moving snow to ride up and get broken before it reaches the pipe.

[marson]

Kind of depends on how much snow you are talking about. In the cascades in Washinton, I've seen snow bend the edge of heavy gauge steel roofing right over the eave, and would snap an ordinary plumbing vent like a match stick (vents would have to be cast iron and pierce the roof at the peak). I guess I think your idea will work, but you are going to have to engineer it to be pretty stout. Also, the snow will probably just hang up and stay up there, which maybe isn't so bad.

[Mamba]

Thanks! That Ventsaver on Snowjax looks like just the ticket. Simpler than my idea too. Appreciate the tip.

[Mamba]

heh heh. Actually we are just east of the Washington Cascades, but far enough east that the annual precip is pretty light. This year we have far more snow than in the previous five that we've owned the place.

Another respondent suggested a product that I think will work, it's at least worth a try.

Thanks for the feedback.