Snow fence needed?

[AaronMcD]

I don't usually work in freezing locations, but currently working on a house with a 45 degree metal roof, no drift or unbalanced load, just straight 30 psf sloped slippery roof snow load throughout.

1) Is a snow fence really needed on this roof?
2) If we use a snow fence at exit/entries (a patio) should I just treat it as non slippery? (slippery roof snow depth = 15 inches)

 

[SWComposites]

can you put a gable over the entries?

 

[structSU10]

there are procedures to sizing snow guards that are fairly prescriptive. Some assume the tributary snow up the roof creating an 45 degree angle exerts the load on the guard.

Most manufacturers have their own method of doing it and in the US it generally a delegated design. You can speak with a supplier but most would likely recommend their use and could be considered biased in their opinion.

 

[dauwerda]

1) As you know, snow guards are to prevent accumulated snow from sliding off the roof onto people as they enter or exit the building. I don't believe they are specifically required by code, but I know I would want them on my house.

https://www.foxnews.com/us/snow-from-idaho-cabin-roof-buries-3-children-1-dead-2-in-hospital

2) Yes, as you are preventing snow from sliding off, you wouldn't want to use a reduced load assuming it will slide off.