Roof Snow Stops

[CBSE]

When it comes to a metal roof with snow stops on it to prevent snow from sliding off, how are people treating this snow load condition?

1) Just assume typical unbalanced snow?
2) Some sort of snow piling effect...I'm not sure how to account for that
3) Different roof adjustment factors?

I'm not sure how to treat it. I know that there will be snow piling at that location, but maybe the unbalanced snow load accounts for this?

 

[msquared48]

If at an entrance, I try to encourage the Architect to put in a gable condition and still allow the shedding to occur, just reinforcing the valley area.

I will have to defer to others for their experience if this is not the case.

Mike McCann, PE, SE (WA)

 

[medeek]

Metal roofs are usually considered "slippery", with snow stops I would consider a metal roof "non-slippery". Section C7.4 in the ASCE 7-10 offers a bit of guidance.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com

 

[dcarr82775]

1: I have used unbalanced or drift, whichever is bigger
2: I have not included 'piling on' effects. I have always viewed these as preventing the snow from moving. Once things start moving the resistance required to stop it moving gets pretty unreasonable and the roof framing/diaphragm can become problematic.

 

[CANPRO]

agreed with medeek...the only difference the snow fence has made to me is that you cannot count on the snow sliding off of the roof. Typical snow fence is less than 16" tall anyway which is likely less than the basic accumulation of snow, so it makes sense that there wouldn't be any additional buildup on account of the guard.

 

[CBSE]

Thanks for the info. I will be treating it as a "non-slippery" roof.