You may try to install some icebreaker devices on the edge of the high roof
to break up the snow as it falls. This is commonly done in locations where
the falling snow/ice would not hit a low roof, but would land on someone's
Bruce Resnick, SE
Parker Resnick Str. Eng.
In a message dated 5/27/99 11:21:41 PM Pacific Daylight Time, rvogel(--nospam--at)jps.net
This topic is along the lines of a problem that I will soon have to address.
Several months ago Kirkwood Ski resort called me to look at a roof that had
a failure. It seems that a large glacial like chunk of ice (rough guess 10
tons) fell about 20 feet from an upper roof and shattered some rafters at
the front of the general store. It turns out this is the second time that
this has happened.
A little aside, it seems that architects rarely listen to warnings
explaining all the possible affects of sixty feet of annual snow fall.
The lower roof was originally 3x6 rafters at 2' oc spanning about 5'. The
first time they failed they replaced them with 4x6 at 2'oc. Five or six of
these 4x6's at the impact area were reduced to splinters. The snow load at
this area (Pf) is 300 psf, the funny part of the story is that this roof
never has any snow on it. The upper roof tends to acculimate snow at an
adjacent valley area and then gradually creep until it eventually falls to
the unloaded roof below, then bounces off and lands in the parking lot. I
gave Kirkwood a temporary repair last the winter, and told them to call me
this summer for a permanent repair. I think that I will have fun trying to
come up with a reasonable but safe impact load for the new roof.
Randy Vogelgesang S.E.
South Lake Tahoe >>