Ice Dams

[Bob]

In the late summer early fall I am planning to have heat tape installed on both the front and rear edges of my home. I have an horrific problem with ice dams. I have a full length ridge vent along with 9 inch vented overhangs front and rear of the home and still get damming. I have 48 inches of water protection and have not had any problems with water entering the home as I shovel the complete roof and steam channels every snow event. I have gotten several estimates on a metal roof but it would be a sin to tear up a new architectural roof so early in its life. Wanted to get some feed back regarding this option or I'm I missing something with the proper ventilation of my 3/12 roof cavity.
Thanks in advance for any assistance Bob

[Mark]

You have that much snow and only a 3/12 roof pitch? yikes

Do you have any venting other than the ridge vent?
Potential venting of bath/dryer/kitchen into the attic?