I just tackled this situation. Here's what happened. I had a building and
we put a 25 foot high penthouse in the middle of the flat roof. This new
penthouse now created a profile for which snow would drift against.
Since the original roof was only designed for a ground snow load Pg, we
projected a cantilever canopy (we called it a snow platform) out from the
NEW Penthouse just above the elevation of the original roof surface. The
cantilever extended out enough to pick up a portion of the triangular drift
load and thus limit the load to the existing roof structure to less than the
Pg load. Of course we had to pick up the cantilever load in the penthouse
structure, but we did avoid reinforcing the lower roof.
From: Pat Ebner [mailto:PEbner(--nospam--at)younglove-const.com]
Sent: Wednesday, June 21, 2000 3:36 PM
Subject: Snow Drift Loading.
A project manager just came in and asked if I had ever heard of basically
building a sloped roof on a lower building to eliminate the snow drift load.
He has a building which is to be built next to a shorter existing building,
which was not designed for a snow drift load. I have not heard of anything
like this. Has anyone done this or knows if this would work?