VentMASTER Attic Ventilation Solving Heat, Mold, and Ice Dam problems


Defending Your Home Against Ice Dams

To reduce the possibility of ice dams, VentMASTER uses a three-step approach:


1. Good Attic Ventilation

Ice dams form when a roof has warm upper surfaces and cold lower surfaces.  The solution is to equalize temperatures over the entire roof and the most effective way to equalize temperatures is to create a cold roof.

Ice dams
To do that, you need a well designed attic ventilation system that supplies airflow along the entire underside of the roof deck. This is critical, because only uniformly distributed airflow reduces variation in roof temperatures from peak to eave.

One of the most efficient and effective systems (from both a cost and performance standpoint) uses ridge vents and an evenly distributed layout of intake vents.


2. Adequate Attic Insulation

Attic insulation serves two purposes. First, it reduces heat loss from the home’s living quarters.
Since heat loss is a key factor that contributes to the creation of ice dams, it is important to stop it at its source.
Second, adequate attic insulation reduces the energy impact of having cold air flowing through the attic.


3. Waterproofing Shingle Underlayment (WSU)

Event the most efficient attic ventilation system may not be enough to eliminate ice dams. A
combination of weather conditions, roof pitch, building orientation, and other factors sometimes allows
ice dams to form under specific conditions. If that happens, a WSU barrier minimizes
– and possibly eliminates – water infiltration into the structure of the building.

The Problem With Heat Cables
Using heat cables to melt ice on a problematic roof where heat escaping from the house already produces the potential for ice dams is like using a band aid after open heart surgery. Why?

  • Heat tape only melts ice a few inches from the cable. This leaves many areas unprotected.
  • The zigzag melting pattern creates limited and selective removal of snow and ice. This causes up-roof ice dams.
  • It needs constant monitoring. You have to be home to turn on the cables (no winter vacations!).  Passive systems consisting of soffit and ridge vents, along with good insulation do not need constant monitoring.
  • Possible fire hazard.
  • They can ruin the look of your house.
  • The cost: installing cables is often more expensive than installing insulation and ventilation. Also, the energy costs for operating heat cables is significant, on-going,  and RISING!