Ice is also found on cars, sidewalks, dog houses, roads etc etc. Its a natural occurrence when snow melts and refreezes.

Note how bright the sky is. The sun with or without temperatures being above freezing mark will cause snow to melt

What leads you to believe the insulation is causing this natural occurrence?

Thanks to both of you. I assumed there was damming because of the icicles. I also wasn't sure of the difference between both... It's reassuring to see I might be wrong. Is there a way to check without going on the roof?

Ice damming is typically caused by the existence of an area at the lowed "edge" of the roof that does not have warm air beneath coupled with the upper portion of the roof having somewhat warm air beneath.

In the classic case there is an attic with eaves extending out beyond the sides of the home. With the loss of any heat in the attic thru the roof directly above there is the potential for melting of the snow.

There is no heat, or at least virtually no heat, beneath the eaves area therefore the snow above does not melt.

The melted snow from the large area of the roof above the attic flows down the roof until it reaches the colder eaves area. That water now freezes above the eaves, forming an ice dam. The water now backs up against the ice dam and when enough water collects , the water works itself under the shingles and may seep down into the outer walls or attic.

The water has the potential to evidence itself in seemingly odd places. It may flow down inside the exterior wall and not be seen or hear until it becomes visible around a window in the basement. It might run along your attic floor and pool in a low point and ultimately bring down a plaster ceiling.

In the OP's case, seems an attic is not in play, but heat may be lost thru the insulted great room ceiling and melt snow above. The eaves are presumably not conditioned so the potential exists for an ice dam to form. With foam insulation also in your outside walls I'm not sure what could happen as far as water getting inside that foam envelope, but the potential for roof sheathing damage would exist.

On a nice warm day you could remove a bit of your eaves vinyl and inspect for any history of ice damming.

Some things that can be done to prevent ice damming might include: additional attic/ceiling insulation; a membrane installed beneath the shingles for at least ~4 feet before shingling; adding thermostatically controlled electric resistive heating wires in a saw tooth pattern extending that 4 feet to maintain a draining channel.

I'm not a roofer, but I'm sure roof35 or others can tidy up my reply and possibly add other ideas.

@SaltiDawg, at 6 inch = R36 do you think we could have heat loss?

@roof35 : so you think this is caused by normal melting by sun heat?

Of course you will have heat loss. If you had R72 there still would be some heat loss. If you have a temperature gradient across a substance there will be heat flow. The issue is the amount of loss.

The snow on your roof is being heated by a combination of direct sunlight and heat loss from the structure.

You can take a lot of the guess work out by having thermal imaging done.

By guessing, you can attempt a process of elimination. If the ice cycles are more prevalent on the same side at which the sun sets. Then I would conclude the sun is playing a major role.

Also attempt to compare conditions with neighboring structures. My own home has R49 in the attic with proper ventilation (which I know you have none). My structure has snow still up there when all neighboring structures have none. However, on the west facing gable I get ice cycles and none on the other. Once the sun sets, and it's in the teens, instant freeze.

Icycles are on the side that actually never sees sun... because that's the longest and steepest slope. The side where the sun sets is flat so no chance of getting icycles there. But I got your point, maybe I'm overthinking it. I always thought about comparing with neighbors but keep forgetting to check when I pass by (we don't live there).

@SaltiDawg yeah I guess what I meant is : at R36 can I have enough heat loss.

Thanks to both :)

This often happens on north facing roofs where the snow doesn't melt away quickly in the sun and run off as water. It melts a little and slides down toward the gutter, then refreezes at night. It doesn't require heat from the structure if the weather is just right (not too cold, not too hot).

I built a basically unheated metal shop building with a metal roof here in MO and was advised not to put gutters on the north side as the ice dam will slowly and inexorably curl into the gutter and tear it right off like a giant fist. Solely due to the warming and refreezing of day and night.

This is why low sloped roofs are not recommended for cold climates.

Actually, in New England it is snow loading that drives the roof to a higher pitch. Ice damming can occur with any pitch.