Dangers of Ice Damming | Roof Icicles

Ice DamsDrive around West Michigan, or any climate with snow, in the winter and you will see homes all over the place with icicles.  Some small and some so massive that they touch the ground.  They look kind of cool, but unfortunately they cause problems and can be very dangerous.  A properly built home should not have any ice damming no matter how harsh the winter is.  Why is this?  Well ice damming is caused by a very specific problem in most cases.  With the technology and information we know today about ice damming, there should not be any on new construction homes.  Period.  This picture is showing a massive ice dam on a home that was build within the last 10 years.  It has caused major leaks inside the home as well as structural issues that have caused the roof to sag.  Unfortunately this was all caused by a builder and insulation contractor not understanding building science.  This mistake will cost thousands and thousands of dollars to fix and probably end up in court.  This is why it is so important to have a building science consultant on your team.  As you are driving around notice how most of the icicles have formed on older homes.  Drive in on some new home neighborhoods and you will see most of those homes will have no icicles.  There is a reason for this and its not just by coincidence.

What causes ice damming?

Most homes in Michigan have what is called a vented attic.  This means the goal is to try and get the attic to a similar temperature as the outdoors.  Unfortunately many homes are not able to accomplish this.  The main reason for this is due to inadequate air sealing and insulation between the conditioned space of the home and the attic.  Meaning warm conditioned air is leaking into the attic during the winter.  This in turn causes the attic to heat up as well as the roof deck.  As snow accumulates on the roof it will begin to melt and the water will run down to the eaves.  The eaves are not being warmed up by the attic so they are much colder and cause that melted snow to re-freeze and form icicles and ice dams.  This process continues to repeat itself over and over again throughout the winter.  A secondary cause of this problem is inadequate attic ventilation.  Improved attic ventilation alone will not get rid of ice damming, but it will help cool off the attic and potentially get rid of minor icicles.  Don’t get me wrong, do not skimp on the ventilation because it is very important for other reasons besides ice damming.

How to prevent ice damming?

Eliminate heat loss and air infiltration into the attic.  Simple as that.  Well unfortunately it is not always simple.  In some cases, especially in older homes, it is very hard to completely get rid of ice damming, unless you do a major renovation.  Air sealing is number one!  Seal top plates and any penetrations into the attic.  Make sure the attic is completely insulated to above code recommended R-Value.  Next, make sure the attic is properly ventilated using continuous soffit vents, baffles and ridge vent (or traditional roof vents).  If you have a furnace or ductwork in your attic, you really need to consider doing a sealed attic.  That means all ventilation is terminated and the roof deck gets insulated with an insulation that also acts as an air barrier, such as closed cell spray foam.  Essentially the attic becomes part of the conditioned space.  See both pictures below of a properly designed vented attic system.


Baffles & Attic Venting


























Problems caused by ice damming

Ice damming causes roof leaks, shingle damage, roof sheathing damage, wood rot, roof deterioration and structural issues. Not to mention the roof icicles create a dangerous situation for anyone that is at your property. Don’t ignore this problem before it is too late. Call us and we can help solve your ice damming issues.