In 1984 I was the smartest man alive. I graduated from a business school with a 4.0 average. I was working in northern maine planning to be the next lumber barron. armed with a few copies of Mother Earth news I was going to show the hicks how to build a house that almost paid you to live there. A few examples(but not all) double air gaps and vapor barriers, boxed electric boxes inside vs flush to stop air leaks and last to the point of this post roof a 30/60 90 right triagle to capture the skylight sun so no heat was needed on the second floor.It was in maine. In the last 25 years mother, mother and mother Have hounded me. (mother nature, roof design lets no sun on the north side) ( mother of my children, we have to buy new shoes theirs are mouldy from damp north side closits) My mother , why don't you just put up heat tape so the water runs off. What I have learned in the last 6 years. 1 it is a waste of time to plug in heat tape under 20 F. 2 unplug at night unless it is going to rain. 3 don't let your mother know you listened to her or you will hear about it at christmas and thanksgiving. 4 it is better to spring for the longer tape up front then to chop ice and splice in January. A new question "how does a 75 year old know by dipping her finger in a sugar mix when it is time to glue the waco mints to a gingerbread house. I have to know I might have great grand children someday?

First make sure the Ice & Water Shield is not under the felt paper. It makes no sense for a roofer to violate the contract in such an obvious way. Ice dams will form on any roof slope if there are severe enough freeze-thaw cycles in the winter. That is the factor that will determine whether to fix the error or ask for a refund. Don't worry about the contractor or his opinions. Do you get a lot of snow? Do you get alternating cold and warm days? Do you see large icicles on roof eaves? Do you have gutters? If so, how far below the drip edge are they installed? How far does the roof eave extend beyond the exterior wall?

Ya, that why I said "much" of the problem. I've always increased the size and slope of my eavestroughs to facilitate the ability of that near frozen water to get gone as well. Aggressive slope cures lots and you can trim it or paint it to minimize the street look. We have a few homes in Calgary and it can Chinook on you, be well above freezing and then drop, leading to immense ice issues if you don't get out in front of them. Between air sealing, insulation and good drip edges along with attention to the troughs and downspouts (don't make freezing water travel too far before you divert it down) we have substantially minimized our issues. And Brick is right, each home is a bit different, each geographical location is a bit different and here in Canada we don't have stuff like air handlers, hot water tanks or aircon in our attics, so you have to watch for those variables as well.

The spikes are designed to break snow and ice into smaller and less dangerous pieces, not to keep it on the roof. There are so-called snow guards which act as low fences to keep ice and snow in place. In this situation - which sounds very dangerous - your best course would be to consult a roofing company about the best action to take. This really isn't a DIY job.