How Does Eave Style and Construction Method Affect Ice Dam Formation and Severity?
Eave Construction and Heat Transfer
We have discussed the relationship between eave depth and ice dams previously (Case Study #10). Now let’s look into how different construction methodologies affect the likelihood and severity of ice dams in residential and light commercial construction.
For obvious reasons, eaves are a central topic in the world of ice dams. After all, that’s where 98% of ice dams occur, with the other slice of happening in areas including valleys, flat roofs and low pitch roof pans. There is a reason why older homes are affected more by ice dams then newer homes. That relates primarily to the nature of how the eaves are assembled.
Our grandparents didn’t understand the importance of insulation and ventilation as it relates to the eave. (They were busy thinking about wars and famine). In short, there needs to be enough room between the top plate of the wall and the underside of the roof decking to allow for adequate insulation and ventilation. We know that ice dams are created in large part by the escape of heat from the interior, conditioned spaces of a home into areas where that heat is not supposed to be. Namely, it is not supposed to be in the roof cavity next to the roof deck. Homes with less insulation near the eaves are troubled with ice dams far more than those with adequate insulation and ventilation. In Diagram B, we see an example of common eave construction in modern homes. Notice that the distance between the top plate and the roof deck is quite generous. This is commonly referred to as the heel height. In Diagram A, which shows a hand-framed eave, there is virtually no space for insulation or ventilation. Consequently, heat can easily pass from the room below to the roof system, melting the snow above.
Don’t despair if you have old school eaves. There are options to help prevent or at least minimize the likelihood of ice dam problems in the future. Those can be broken down into two broad categories; Architectural and non-Architectural Solutions. In short, Architectural solutions involve modifications to the thermal performance of the home, including insulation, ventilation and, most importantly, sealing air-leaks into the attic or roof truss cavities. The most effective Non-Architectural solution is simple, cheap and effective. Install a high-quality, self-regulating heat tape system on affected areas.
Ask any experienced residential designer, classic architectural styles are difficult to execute with adequate heel heights. Talented designers can pull it off, but they need to think outside the box. High-end, architecturally refined homes don’t look right with clunky, new construction eaves.
Here is why it makes sense to hire professional roofers to remove your ice dams. It’s true. Most of our competitors are not roofers, nor do they understand residential construction.
Ice dam company professional roofers, professional results
Today one of our guys found a massive install error on a low-pitch rolled asphalt roof in Minneapolis. The client had no idea, and nor would any of our competitors who are not construction pros. The original roof installer failed to use adhesive between the roofing plies! (Photo 3, Point E) and no ice and water membrane whatsoever (Photo 3, Point F). That’s a major no-no. They also had all of the penetrations negatively lapped (sequenced into the asphalt improperly) (Photo 4, Point D). Good catch Paul!
The client with the roof leak in Minneapolis illustrated here called due to water pouring in through a light fixture under Point A, Photo 1. This by itself is not unusual. Roof leaks caused by ice dams often manifest many feet away from the source; sometimes a full story or two below the source. My initial theory was that water was traveling down the exterior wall of the shed dormer shown in Photo A. As it turns out, there was something more pernicious happening. The water was being pushed under an improperly flashed plumbing stack (Photo 2, Point B). While exploring the area our crews also noted the lack of lap sealant between the roofing plies (Photo 2, Point B and Photo 3, Point E).
This homeowner had used one of our largest competitors in town in 2014 to remove an ice dam (see highest ranking Google result). Guess what? They said nothing about the roofing defect. No big surprise because frankly, how would they know? They aren’t construction professionals, just ice dam removal guys who squirt ice off roofs with high-temperature pressure washers (not steamers!) (Click here to see the difference). We have seen this exact scenario play out countless times and to be honest, it’s frustrating to watch.
Ice dam company finds roof leaks
The Ice Dam Company is in fact the only company in the country with the in-house chops to diagnose and address problems with insulation, ventilation, roofing, sheet metal and other exterior envelope components. We also install miles of self-regulating heat cable each year on homes where the aforementioned architectural solutions are not appropriate or feasible. Most ice dam removal guys just use their pressure washers to squirt ice off the roof and that’s the end of it. For us, ice dam removal projects are often just the beginning of a longterm relationship with our clients. We end up remodeling their kitchen or adding onto their house through our sister company Kuhl Design + Build, a nationally recognized, award winning remodeling firm. The Ice Dam Company is a division of Kuhl’s Contracting, the third largest residential construction and remodeling company in Minnesota. There is a huge amount of cross-pollenization between the organizations. Each benefits from the resources and talents of the other. It’s fun to witness.
Ice dam company fixes roof leaks caused by ice dams and construction defects
How to Prevent Ice Dams on Your Home – Answers from the Experts
To be frank, the entire concept of ice dam prevention is a little bit disingenuous. There are certain circumstances where even the most well constructed, well insulated and ventilated roof system will get ice dams. Those situations are rare, but they do occur. When we talk about ‘prevention’, what we are realistically discussing is the field of work aimed at either reducing the likelihood of ice dams or minimizing the impact of ice dams if they do occur.
Two Approaches to Ice Dam Prevention:
We break ice dam prevention into two broad categories; Architectural and Non-Architectural. Architectural solutions involve modifications to the existing structure to alter the problematic thermal characteristics that are contributing causes of ice dams. In contrast, Non-Architectural solutions are comprised of the work done to minimize the impact of unwanted roof and gutter ice accumulations when they are likely to begin.
It’s seldom the case that a single home medication, once implemented, will permanently fix an ice dam problem. More often than not ice dam prevention involves a combination of changes in order to have a significant impact.
A very standard ice dam prevention project for The Ice Dam Company might involve enhancing or replacing the insulation in the attic or roof system, adding ventilation and sealing all of the air-leaks between the heated spaces and the attic and roof framing. Usually, this combination of endeavors yields good results. Sometimes it is necessary to alter the roofing system itself. Normally, this means installing a single ply roof system such as hand-soldered copper pans or a rubber membrane. Single ply roof systems are quite resilient in the face of ice dams but they will to work in all areas due to aesthetics. We will dig further into each of the three basic architectural solutions in other Case Studies.
Certain ice dam creation factors cannot be addressed through Architectural solutions such as insulation, ventilation, air-sealing or roof system enhancements. Case Study #19 discusses the relationship between the sun and ice dams. We recently installed heat tape on a 6 year old, $3.8 million dollar home. The homeowner had spared no expense relative to energy efficiency in the original design and construction. That was not the issue. The problem was simply that the sun was melting the snow on an exposed roof plane higher on the home which resulted in melt water running down to a cold eave area that was hidden from the sun. There it would re-freeze in cycles to create an ice dam that kept coming back year after year.
In terms of ice dam prevention, there is a small set of options available that fall outside of the Architectural solutions. These involve systems to manage snow and ice accumulations as they develop on a roof. The most popular Non-Architectural ice dam solution is heat cables. Otherwise known as heat tape and roof deicing, heat cables are wires that warm up in response to electrical current. Typically, heat cables are installed in a serpentine or zig-zag pattern on a roof along the eaves. To be clear, heat cables do not resolve the underlying issues related to why ice dams are happening rather they help manage the issue of unwanted ice accumulations when the conditions are ripe for their formation. A common complaint about heat tape is that it does not address the real issues causing the ice dams. This complaint is justified because it is true. That said, heat cable systems can be installed on a home for a fraction of the cost of traditional Architectural solutions. Many homeowners are not in the position to spend $5,000 to $25,000 for Architectural ice dam solutions making the idea of a $1,000 heat cable system very appealing. We do both approaches every day.
We would be remiss in not mentioning the very most basic thing you can do to minimize the likelihood of ice dams; Roof shoveling. Diligently removing the snow from your roof can greatly reduce the likelihood of ice dams. Unfortunately, some roofs are too high or have areas inaccessible to the average homeowner, making roof snow removal an ineffective approach to guaranteed ice dam prevention. Removing all of the snow from the roof planes affected by the ice dams is very important. See the Ice Dam Company Case Study #3 that discusses a phenomenon called the ‘Double Dam’.
You may notice that the home shown below has some icicles (sarcasm intended). Obviously, when something like this occurs, it is quite likely that you have ice dams as well as a giant insurance claim from the subsequent water damage it has caused. The fact is, the vast majority of the ice dam steaming projects we complete are not on homes with monster icicles. When we arrive we often see quite modest icicles from the ground. The relationship between icicles and ice dams is not difficult to understand when you study the problem for awhile. This Case Study digs into the topic of icicles and ice dam life cycles.
Do icicles mean ice dams? The short answer is NO. While icicles on the edge of the roof are often a precursor to ice dams, they are not always present when ice dams begin to cause leaks through a roof system. Ice dams and icicles are part of the same accumulation but they are not the same thing by any means. This brings us to the normal life cycle of an ice dam.
The characteristics of ice dams change over time. The typical lifespan of an ice dam rangers from a few days to a few weeks. During that time it may get thicker or thinner, icicles may appear and disappear on its’ leading edge, and it may be almost completely hidden under snow or partially or completely exposed. For this reason, there is a big different between a young ice dam and an old ice dam in terms of the presence of icicles. Very young ice dams often have visible icicles on their leading edge. Over the following days most ice dams tend to grow more in depth than thickness, meaning the ice migrates higher up on the roof plane (refer to Case Study #06 for more information). Icicles on more mature ice dams tend to melt away from the affects of direct sunlight or warmer outdoor temperatures. However, while the telltale icicles may be missing, the mass of the ice dam is left behind, frequently hidden under a blanket of snow.
The photos above (A) and (B) demonstrate this phenomenon on two St. Louis Park homes. Virtually no traditional signs of an ice dam and yet you see water leaking down the exterior wall, through the siding and in the wall cavity itself. Bad news.
Case Study #16 examines the important topic of ice migration, from icicles to the interior of your home.
HeatTapePro is a premium brand of commercial-grade, self-regulating heat cable. We are strategic partners with the Radiant Solutions Company, the direct manufacture of HeatTapePro and all related installation accessories.
Ice dam roof deicing cable installation information
HeatTapePro self-regulating heat cable
HeatTapePro self-regulating heat cables are designed to be used for a variety of roof de-icing, gutter de-icing and pipe freeze applications. Self-regulating heat cable automatically calls for more energy when ambient outdoor temperatures are lower and conversely, less energy when outdoor temperatures are higher. HeatTapePro is pre-terminated in our factory for your safety and convenience. No field modifications will be necessary to the cable to use it for the described purposes.
The Relationship Between Sunshine and Ice Dam Formation
Ice dams happen when there is a section of roof that is above freezing (32°) where roof snow melts which then drains to an area that is below freezing, usually the eaves, where it refreezes. The source of this temperature differential is usually the result of interior heat loss, specifically via air leaks and insulation issues. In fact, according to our experience, 95% of our client’s ice dam problems can be mitigated or eliminated altogether through the modification of the thermal characteristics of the home. Still, we see ice dams on certain homes for reasons outside the scope of it’s architectural deficiencies. Homes with what we might call nearly perfect air-sealing, insulation and ventilation still get ice dams. This Case Study describes such a situation.
The winter sun hits Minnesota homes (and all homes in this latitude) at a low angle during the winter. The result is that certain roof slopes never see direct sunlight while others get hit quite directly. The above illustration demonstrates an ice dam situation that relates to the heating effects of the sun. Solar radiation warms the roof slope on the dormer (1), the resulting melt water drains to an area of the home (2) that never sees direct sunshine where it refreezes to form an ice dam (3). These are particularly challenging ice dams to prevent. Often times heat tape, also known as heat cables, are the only affordable option.
What Frost Melt Patterns Can Tell You About Your Home
Insulation and Ice Dams
At their most fundamental level, ice dams are the result of the interaction of heat loss and snow on your roof. An experienced Ice Dam Company Thermographer can use photos like these in conjunction with infrared imaging to see the weak points in your home’s thermal envelope. If you have a moment on the next frosty morning, take a few photos of your roof from a few angles before the sun hits it. Those photos may end up saving you time and money if you are hoping to fix the root cause of ice dams and home heating inefficiencies. Of course, ice dam prevention involves more than simple insulation job, but understanding the basics through frost pattern analysis, thermal imaging and a good site inspection is a great place to start.
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.
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: