Houses with good attic ventilation generally do not experience ice dams and the physics are quite simple.
Ice dam no attic.
The good news is there are several ways you can prevent ice dams if you ve got a cathedral ceiling.
Ice dams can be a real problem in winter.
That s why attic fans are a non starter for ice dam prevention.
The cause of ice dams on the roof can be explained in two words excessive attic heat.
To protect against damage to your structure and to reduce energy usage.
Simply insulating your attic will keep your home warmer and your attic cooler.
The bad news is you ll need a good contractor to help execute them.
Although excess heat moving from the attic through the roof rapidly melts snow once the meltwater touches the cold eaves it quickly freezes and forms an ice dam.
In the tutorial it also describes some of the preventative things you can do before winter including.
Ice dams and icicles form when the snow melts runs down your roof and refreezes near the edge.
Ask this old house general contractor tom silva explains the best ways to keep your roof and gutters free from those dreaded ice dams.
Proper attic ventilation can prevent ice dams.
The result is that the snow on the roof melts unevenly usually leaving huge chunks of ice intact along the roof edge but with melted snow behind.
This water finds cracks and openings in the exterior roof covering and flows into the attic space.
This scenario is often the result of a warm attic.
See below for a shopp.
Because most of my advice is for people who have attics and you ve got a cathedral ceiling you simply don t have an attic.
There are several means of improving attic ventilation.
There are two main purposes of attic ventilation.
The dam grows as it is fed by the melting snow above it but it will limit itself to the portions of the roof that average below 32f.
Excessive attic heat causes some areas of the roof to be warmer than others.
If you have a furnace in the.
In addition seal all the places that warm air can escape into the attic like areas with wires and plumbing lighting fixtures heating fixtures chimneys etc.
This only occurs when part of your roof warms to above 32 degrees f warm enough to melt the snow while the roof edge remains below freezing.
Ventilation during the winter helps to reduce moisture as well as keeps attics dry and at an even temperature.
Have a contractor create an air barrier.