Ice Damming?

[Descant]

Not necessarily dams, but water damage can occur when the snow is so deep and soaks up rain, that the weight bends the rafters separating joints. Time to shovel, not just rake the eaves. Hire somebody. If he falls, he collects worker's comp for a few months and is back to work. If you fall, you have to live with "What were you thinking?" for years to come.
Depending on conditions, I sometimes throw salt tabs on the roof. They're intended for this use and look like a hockey puck. Most of my roofing is pretty steep-cape style. Even so, last replacement we doubled up on the Bituthane/ice and water shield. I think most roofers nowadays do that automatically, but I've been here over 45 years, so some sectionms and some other buildings are part of a rotation.

[John Mercier]

Originally Posted by Descant

Not necessarily dams, but water damage can occur when the snow is so deep and soaks up rain, that the weight bends the rafters separating joints. Time to shovel, not just rake the eaves. Hire somebody. If he falls, he collects worker's comp for a few months and is back to work. If you fall, you have to live with "What were you thinking?" for years to come.
Depending on conditions, I sometimes throw salt tabs on the roof. They're intended for this use and look like a hockey puck. Most of my roofing is pretty steep-cape style. Even so, last replacement we doubled up on the Bituthane/ice and water shield. I think most roofers nowadays do that automatically, but I've been here over 45 years, so some sectionms and some other buildings are part of a rotation.

The hockey pucks can cause ''ponding'' so they have to be watched to make sure the water has an exist to the eaves and not just absorption into the snow below them. Steep roofs handle that better.
The problem with over using the ice & water at more than the heat transfer points is the possibility of limiting water vapor. The ice & water doesn't ''breathe'' well.

Before I went to a metal roof, I used an old roof rake with a cup secured to the end. That way I could sprinkle the calcium chloride flakes - same material as the hockey puck - into a vertical pathway that would allow the snow to melt and the water to have an outlet to the eave.