Return to index: [Subject] [Thread] [Date] [Author]

Re: Snow Drift Loading.

[Subject Prev][Subject Next][Thread Prev][Thread Next]
This wouldn't be the first time I misunderstood a question.  Micheal is
right in that if the two roof lines match: fascia are same elevation,
roofs are same slope, and you are building gable to gable then you won't
have any drifting problems.  Basically you need to make the roofs one or
reduce the height difference to that of your initial loading so there is
no room for additional drift.  What is the height difference of the two
buildings?  However, if one building is shorter than the other, when you
pitch the lower roof it will still have an hd.  Granted it may change
over the length of the roof.  But unless the lower roof was initially
designed for the snow drift (doubtful) you will still be exceeding the
design loads. You may have enough reserve to be OK, only you will know. 
Could you give us some more specifics?  I think we are all ultimately
saying the same thing - its possible if your conditions are just right. 
I'm never that lucky.  Let us know how it works out.

Jake Watson, E.I.T.
Salt Lake City, UT

Michael Bryson wrote:
> Correct me if I am wrong, but I think the original question was trying to
> ask if you can reduce your snow drift caused by snow build-up against the
> new building's walls (i.e. reduce hd in Fig. A-16-4). It is my opinion
> that if you built a sloping roof profile matching the drift surcharge
> profile (ie slope=hd/Wd) then the drift surcharge would equal zero. This
> is because drifting is caused by wind blowing dry snow around, and the
> snow doesn't care if it blows over a roof or existing snow. Hence, there
> is no snow build-up.