Perhaps the least costly option is to institute a snow drift monitoring program after a significant snow or winter wind event the roof could be inspected to look for snow drifts at known susceptible areas.
Solution to roof snow drift.
For ordinary leeward drifts the width is 4hd unless hd hcin which case we set the height at hcand increase the width.
Ground snow load pg.
Solutions to these problems are generally self evident e g place air intakes high up on the wall keep windows at roof steps as high above the lower roof as possible locate plumbing vents and.
From our example our ground load and flat roof snow load were found to be 30 psf and 21 psf respectively.
A longer term solution to drifting snow includes building up roads and driveways so that snow is blown across rather than drifting on to them.
By elevating driveways above the surrounding terrain wind will sweep snow off of the roadway.
Lets assume our project is in madison wisconsin and we have already calculated our balanced roof snow load here.
This approach is conservative and simpler but for small gap the width could be 6 hd.
Length of high roof lu.
A sloped metal roof system can be installed directly over the lower flat roof minimizing business disruption.
Determine the direction from which wind usually moves the snow.
Table 1 1 page 3.
Usually the roadway should be 1 2 feet higher than the nearby landscape to make this effective.
Before building a barrier to prevent the build up of snow drifts such barriers are typically called a snow fence you must assess the area where the snow drifts.
The first reason to worry about roof snow is you re worried about a roof collapse.
For adjacent drifts we do not start with 4 hdand then possibly increase the width we start with the 1 on 6 shade line.
Length of roof upwind of the snow drift.
The second reason is you live in an ice dam prone home and you want to prevent ice dams.
Provisions on how to calculate the snow drift surcharge for structures can be found in section 7 8 of asce 7 10.
Sloped retrofit metal roofing solution for lower roof abrasive roofing materials asphalt shingles or aggregate surface build up membranes do not shed snow as well as slippery surfaced standing seam metal roofing.
To prevent a roof collapse the slope of your roof makes a huge difference.