Switching to standing seam roofing

[cordur0y]

I'm in the middle of planning a roof upgrade and could use some insight from anyone with some experience with insulation and ice issues. Right now I've got old corrugated metal roofing, and I'm thinking of switching to standing seam cos it looks better, longer lifespan, all that but I've noticed on similar roofs in my area that snow melts unevenly and then you get those nasty ice buildups along the eaves.
That's got me wondering if it's more of an insulation or ventilation problem under the roof rather than the roofing material itself. My attic isn't the best insulated, so maybe the standing seam would just make the symptoms more obvious? but before I jump into the expense, I'd like to figure out if I should be tackling the insulation and airflow first

 

[slvr22_bd]

It's almost always an insulation and ventilation issue, not the roofing material itself. The standing seam roof just makes the problem more obvious. So what's happening is your old, poorly insulated roof deck is allowing heat to escape from the house and into the attic, melting the snow from underneath. As that melted water runs down to the cold overhang, where there's no heat source, it refreezes. That's how ice dams form. Before you spend a dime on that new roof, you need to focus on what's underneath it. First, you need a good insulation layer to stop that heat transfer. Then, you need proper attic ventilation to ensure the roof deck stays uniformly cold. Get the insulation and ventilation right, and you'll protect your investment in that new roof!

 

[ne0nhorse]

It's almost always an insulation and ventilation issue, not the roofing material itself. The standing seam roof just makes the problem more obvious. So what's happening is your old, poorly insulated roof deck is allowing heat to escape from the house and into the attic, melting the snow from underneath. As that melted water runs down to the cold overhang, where there's no heat source, it refreezes. That's how ice dams form. Before you spend a dime on that new roof, you need to focus on what's underneath it. First, you need a good insulation layer to stop that heat transfer. Then, you need proper attic ventilation to ensure the roof deck stays uniformly cold. Get the insulation and ventilation right, and you'll protect your investment in that new roof!

Thanks for explaining! I'm new to this stuff, I just moved into an old house with a metal roof and saw ice build up last winter. I thought the roof was the issue, but maybe the attic insulation isn't doing its job.

How can I check if the insulation is okay or if the attic has good airflow? And is spray foam better than regular batts for fixing this?