In regards to the idea of a hot edge system on a metal roof it can be helpful.
Patternfor ice dams on a metal roof.
The snow melts into water and t.
This is called ice belt metal panels.
However on a building with a deep overhang it likely will not transfer heat high enough up the roof.
It s possible the ice can get a grip on the raised metal screws commonly used to attach the metal sheets to the roof deck.
An ice dam forms when the roof over the attic gets warm enough to melt the bottom layer of snow.
Why ice dams are dangerous.
If you do not want to install an entire new metal roof you can put metal only where it is really needed to prevent ice dams along the eaves.
So the ice dams still build just higher on the roof.
Metal roofing can help but is not an ice dam panacea.
Ice dams can be frustrating.
The quality of installation is still the key and while a metal roof doesn t have the same weakness as composition shingles that can be lifted rising ice and water a metal roof that is not installed correctly can certainly leak with or without ice dams.
An ice belt a band of metal roofing installed at the eaves helps prevent the formation of ices dams by placing a low friction surface where ice dams are likely to form.
The major issue with ice dams on the roof is that they trap the melting water running down from the top of the roof and thereby cause it the melted water to rise up underneath the roofing shingles and eventually seep through the boards and walls inside our homes.
The hot edge systems i am familiar with do not retrofit well onto an existing metal roof.
Improper attic ventilation should also be assessed and taken into account.
On a metal roof there s almost nothing for an ice dam to adhere to.
Metal roofs ward off ice dams pretty well to begin with but a steeply pitched metal roof is kryptonite to an ice dam.
Ice belt metal panels are typically short 3 4 and wide 2 5 3 and are made of thin gauge aluminum.