How the Distribution of Snow Can Affect the Formation of Ice Dams
Snow and Ice Dams
There is a complex relationship between snow and ice dams. Yes, you need snow to get ice dams. Snow is, after all, the fuel that feeds the formation and growth of ice dams. Furthermore, it is unlikely to get ice dams unless there is an ongoing layer of snow on your roof over a period of time (normally at least 7-10 days). But it takes more than just having snow on your roof to get ice dams. See Ice Dam Company Case Study #23 for a list of contributing factors. One factor that seldom gets discussed is the affect of wind on the formation and severity of ice dams. While this is not a primary factor, it is something worth exploring. This Ice Dam Case Study looks at the affect a thinning snow cover has when seen on a roof slope that also faces the sun. The affect described below is exacerbated by the presence of darker roofing materials as they absorb more solar energy than lighter materials.
Mountains and Roofs Share Something in Common
Any skiers out there? Wind speeds increase near the ridge of a roof just like the top of a mountain. Snow on one side of the ridge is often swept away while remaining in place just on the other side of the peak. This phenomenon can affect both sides of a roof if wind direction changes from day to day, leaving the snow coverage thin or non-existent on the upper few feet of the roof below the ridge.
Condensation, The Silent Killer
The lack of an insulating snow blanket can allow heat from the inside of the home to meet cold exterior air in a thinner ‘conduction plane’. When heat hits a thin surface such as a roof decking, where there is a great temperature differential from one side to the other, condensation is also likely. Think of frost on old, single paned windows. The more space there is between the heat and cold, the more room there is for this interaction, greatly reducing the likelihood of condensation. A thick blanket of snow is a perfect insulator for this purpose. It creates more separation between the warmth being lost from the home and the frigid exterior air. Homes with thick snow coverage on their roofs generally seen as more efficient because heat is not escaping through the roofline to reduce the snow through melting.
There is a lot of misinformation out there on the topic of ice dams. Our goal here is to be the single definitive source for all things relating to ice dams. Towards that end, here are some common misconceptions about ice dams, roof snow, roof ice and gutter ice removal.
FACT: Ice dams can occur with virtually no snow on your roof. It’s a question of ice accumulations. It takes very little actual moisture to form ice dams. Even a dusting of snow can create a problem. Of course it is most often the case the thick snow accumulations create ice dams more quickly, but don’t be fooled into complacency because it’s a low snow season. See Case Study #09.
FICTION: Gutters have something to do with ice dams. The truth is gutters have nothing whatsoever to do with ice dams. See Case Study #03 for proof. If your home is prone to ice dams you will get them regardless of whether or not you have gutters. If you have gutters they will fill with ice and provide a foundation for the ice dam above. True. If you don’t have gutters, the ice dam simply builds on the cold edge of the roof. We provide ice dam removal for many homes each year that do not have gutters. In fact, some of our repeat clients have removed their gutters upon the advice of a dumb person only to be shocked that the ice dams came back the season after. Whoops.
FACT: Gutter systems can be damaged by ice. We see it every year. A section of otherwise fine gutter is either on the ground or hanging pathetically off the edge of the roof, filled with ice. Ice weighs about 60 pounds per cubic foot and gutters are not designed to tolerate that sort of load. It’s important to initiate gutter ice removal sooner than later for this reason. See Case Study #11 for common ice dam damage.
FICTION: When it comes to insulation, the more the better. Improperly insulated homes are just as bad as under insulated homes when it comes to ice dams. We have fixed countless bad insulation jobs for this reason. Specifically, we frequently find insulation done in such a way as to inhibit proper ventilation. Moreover, if you don’t address air leakage into the attic or rafter spaces, all the insulation in the world won’t prevent ice dams. See Case Study #04 for details about good eave ventilation.
FACT: You can’t always see ice dams from the ground. It’s true that you can often spot a monster ice dam quite quickly. It’s easy to spot the two foot icicles and the little adjoining glacier on your gutter. The sneaky ones are usually above skylights or in roof pan areas far out of sight. Sometimes ice dams grow up valleys and on top of dormers making it almost impossible to identify from the ground. See Case Study #02 for more information on where ice dams form on residential homes.
FICTION: Salt socks are a smart way to address ice dams. People use pantyhose, old socks and store-bought cloth tubes filled with a variety of ice-melting compounds for removing ice dams. Corrosive substances like rock salt, sodium chloride, calcium chloride, magnesium chloride and more to melt channels through their ice dams. Some compounds are better than others, but all present risks you should keep in mind. Some of the aforementioned chemicals affect the integrity or color of your roof, some are corrosive to the aluminum when gutter ice is removed this way, some are corrosive to valley metal and other flashings, some damage plant life as the water drains below. You are rolling the dice when you go this route so be aware. See Case Study #13 for more information on salt socks (salt in pantyhose).
FACT: Ice should be removed by steam. Here is the skinny. We are roofers and have fixed hundreds of roofs that have been damaged by well-intentioned professionals with hammers, picks and hatchets in their pursuit of removing ice dams to help their clients. The damage we have found caused by the less-than-professional souls is almost funny if it wasn’t so serious. In our years we have seen jobs with picks and hammers where removing ice dams was done successfully. It get’s down to the question of whether you want to take that risk? We strongly advise against the hack-a-teer approach even if it is a little cheaper. Roof Ice and Gutter Ice should always be removed with steam.
FICTION: Ice dams need to be thick to cause a problem. Ice dams as thin as one inch can cause big problems. A good general rule is that the steeper your roof, the thicker the ice dam has to be to cause problems. On lower pitched roofs even a thin ice dam can hurt.
FACT: The leaking caused by ice dams may not show up right away. It would be nice if water stains or mold manifested immediately upon entering your home but it simply does not work that way. Often the water that ice dams push into homes travels around wall and ceiling cavities, trapped by vapor barriers and other materials until it finds the path of least resistance to escape. By the time you see water inside, it’s usually been there for a while, which results in mold and mildew.
The Factors that Determine Ice Dam Removal Cost and Pricing
Ice Dam Removal Pricing
Generally speaking, you can expect to pay somewhere between $300 to $600 per hour for ice dam removal with steam. As much as you may not want to hear this, with over 25 years of experience behind us, we can tell you that the primary driver for ice dam pricing is classic supply and demand. Every market will have a different demand for ice dam removal and a different supply of qualified contractors to perform that work. (See Econ101 from your freshman year for further details). Back to the word “qualified”. There are dozens of companies in the Twin Cities market right now who are using ice picks and hammers and axes to remove ice dams. They normally charge less per hour than ice dam steaming contractors. There are also scores of competitors using high temperature pressure washers and calling them steamers (hint: 2 of the top 3 Google results in Minnesota). Yikes. In the Minneapolis market we profit by following the work of the aforementioned “professionals” by repairing the damage they’ve done each winter with pics and pressure washers. It’s hurts to pay for ice dam removal. It’s extra painful to pay for repairing the damage left behind by losers.
Ice Dam Removal Speed
There are many factors that go into determining how long an ice dam takes to remove:
Roof height (Higher = More difficult)
Roof pitch (Steeper = More difficult)
Snow load (More snow = More time)
Site protections time (Property under the work area needs to be protected to prevent damage from falling ice and snow)
Ice dam thickness (Thicker = More time)
Ice dam depth (The further it has grown up the roof, the longer removal takes)
Outdoor temps (Colder = More difficult)
Ethics (Lower ethics = More time spent)
Having two members to the crew is not only important to safety, it is essential for efficiency. One guy cuts and one guy throws the ice chunks.
To Chunk or Not to Chunk
There is a big difference between ice dam removal COST and ice dam removal PRICING. Pricing is what one typically pays per hour for the work to be performed. Cost relates to how long it takes to do the job. In our list of the 8 factors that determine ice dam removal cost, #8 is the most important. That’s what the photos in this case study are meant to illustrate. Ethical ice dam removal guys do it like shown and they use steam, not high temperature pressure washers. It’s called ‘chunking’. The idea is simple. Use the steamer to cut the ice dam into chunks that can be picked up and thrown off the roof. Cutting ice is the part of the job that takes the longest. Add to cutting time, add to the job cost. The alternative is to use the steamer-or pressure washer if you’re totally smarmy-to methodically melt away ALL of the ice from the roof, one square inch at a time. As shown here, one only needs to actually melt about 5-10% of the ice in order to remove the ice dam. Make slots and undercut. It’s that simple. What the less ethical players do is also simple. Melt all of the ice, milk the clock and watch the dollars add up.
The Truth About Gutters and their Relationship with Ice Dams
In 2011, Ice Dam Company owner Steve Kuhl wrote a nationally published article about ice dams for the Journal of Light Construction. One of the topics that receieved the most attention was the notion that gutters have nothing to do with ice dams. Here is a deeper look at that assertion.
There is a great deal of confusion and misinformation about the relationship between gutters and ice dams. Many people are under the misconception that gutters cause ice dams or that gutters filled with ice can cause water to back up into homes. Not true. We repeat. Gutters have nothing to do with ice dam formation or severity. For this reason, buying systems that heat gutters in order to prevent ice dams is a total and complete waste of money.
We know that ice dams occure when:
Escaped heat from the inside of the home warms the roof deck.
Melting snow results in water that runs down to a cold, unheated area of the roof (frequently the eave, as shown below).
That water freezes, forming ice. After many of these cycles, that ice piles up to form an ice dam.
Study the illustrations below. These are identical eave designs, one with gutters, the other without. The Area B in the diagrams below is referred to as the ‘cold edge’ of the eave because heat from the interior of the home doesn’t travel that far. Fact One: Whether or not a home has gutters, a cold edge will still exist and this is where ice dams form. Fact Two: leaks from ice dams occur in Area A, at the leading, top edge of the ice dam where water–with nowhere else to go–is forced up under the roofing material and into the home. Put another way, if the home in Figure 2 had bad leaks inside, those leaks would not be eliminated whatsoever if we took a chainsaw and cut off the gutters along the red dashed line (C). Moreover, if we heated the gutters using a fancy electrical system, the likelihood of ice dams and the subsequent leaking would NOT be affected. Spend money on heat cables for the lower edge of your roof, not on heating the gutters only. High quality heat cables can be quite effective in preventing ice dams.
Figure 1: Ice Dam Without Gutters; Figure 2: Ice Dam With Gutters
None of this is to suggest that ice in gutters are harmless. We have seen many gutters damaged or destroyed by ice dams and that is a problem most homeowners would like to avoid. The point here is that, all else held equal, if a home is likely to get ice dams the addition or deletion of gutters will be of no consequence to the formation or severity of said ice dams. Likewise, for this reason, installing heated gutters or adding heating systems to existing gutters will have no affect whatsoever on the occurrence or severity of ice dams.
To read more Case Studies click here.
Where Do Ice Dams Normally Happen on Homes? A List of the Most Common Ice Dam Locations
Where ice dams happen…and don’t happen:
Ice dams seldom occur over unheated areas such as garages and porches (A).
The valley areas of dormers frequently get ice dams (B).
Ice dams often occur both below and above skylights. Ice dams above skylights are hard to see from the ground, making them some of the sneakiest to discover (C).
Any openings through the roof – such as pipes and vents – are a good place for small ice dams for form (D).
Valleys are very common areas for ice dam formation. It is important to never use hammers or chisels near valleys as the difference between a thorough ice removal job and valley damage is fractions of an inch (E).
On roofs with a low pitch (angle) even a 1-2″ ice dam can cause significant leaking and interior damage (F).
The eaves edge is the most common place to see ice dams. 80% of the dams we remove are found here (G).
Interior rooms with vaulted ceilings are frequently associated with large ice dams. Bathrooms are often the worst. If you had recessed lighting to a vaulted ceiling, you are much more likely to have ice dams (H).
Ice dams occasionally form around chimneys and furnace flues. Any place heat escapes through the roof line. Ice dams in these locations can be very, very small and still cause leaking (I).
Attic insulation contractor addresses ice dams with new insulation in Edina
Using the words ‘ice dam prevention’ in Minneapolis is a dangerous gamble. It’s true that with certain efforts one can greatly reduce the chances of getting ice dams, it is almost impossible to prevent them altogether. For example, we can do a top quality insulation and ventilation retrofit on a Minneapolis attic only to be thwarted by the fact that the homeowner likes to keep the attic at 90 degrees in the winter. That is a formula for ice dam disaster in Minnesota. There are a number of methods to employ in preventing ice dams (or reducing their severity, in some cases). Here are links to two such approaches used by our sister company, Kuhl’s Contracting, a nationally recognized ice dam prevention company.
Homeowners looking to fix or at least minimize the risk of ice dams in Minnesota are wise to look at the key contributing factors that spawn ice dams. Those are, the weather, insulation, ventilation, air leaks, personal lifestyle and home architecture. We are frequently successful in reducing and/or eliminating ice dams through the use of high performance spray foam insulation systems in combination with enhanced attic ventilation.
construction site ice removal, commercial ice removal, ice accumulation removal minneapolis, ice dam company
We have been called by property managers and builders to remove ice from a number of odd areas in Minneapolis over the years. Heck, we have even removed ice during the summer around cooling condensers at a chemical plant. While we frequently use our high-end steamers for the removal of ice, sometimes they are simply not appropriate. Such was the case on a recent job at a hotel under construction. A thin layer of ice had built up on the surface of a concrete floor that was perfectly flat…and huge. Using steamers in this application would have possibly resulted in making the problem worse by adding more water to the situation. While our steamers don’t generate much water, any time you melt ice, water is the result. Hence, my concern was that we would create a big mess. I suggested that we go old-school on this challenge. I sent three of my guys out there to hack and chip the ice with shiny, new scrapers. The resulting ice chips were simply blown and swept off the concrete, allowing the project carpenters to follow closely behind and lay out the wall framing without concern. It’s a low tech solution but sometimes that is what’s best.
Ice removal minneapolis commercial ice removal from flat surface
Removing Ice Dams in Minnesota: We Serve Many Areas in the Minneapolis Metro
The Ice Dam company based out of Hopkins, Minnesota, about 5 miles west of Minneapolis. We've done gutter ice removal, roof ice removal and ice dam removal all over the Twin Cities, on new houses and old ones.
Some of the more frequent places we've done ice dam services are: