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Ice Dams

Ice Dams... We've all been there.  It always starts off the typical way, you were at home minding your own business when you walked into your guest bedroom to find a puddle on the floor and a ceiling ready to collapse.

So how do you fix Ice Dams if you live in Connecticut or another snow-bound area?  Lets first talk about why ice damming occurs and then we'll talk about stopping your leaks today, followed by keeping it from happening tomorrow.


Why does it happen?

Ice damming typically occurs because of poor insulation and air leaks in your walls and attic; notice the emphasis on 'and', insulation does not necessarily fix air leaks; some contractors may try and convince you otherwise, but now you know! So snow can have an R-value of nearly 1 per inch, which means that the 12" of snow on your roof is providing more insulation than your double pane windows (typically ~R-2). Unlike your windows (hopefully), this snow melts from the heat of your house. What this means is that the heat escaping from your attic gets held in by the snow, and even on a fairly cold day, the deck of your roof can get warm enough to melt the bottom layer of the snow. This leaves you with a hidden river underneath that snow mound on your roof and as it runs its way to the bottom of the roof it refreezes as it gets to the cold section past your outside wall.  This causes both the large visible mass of ice you see ripping off your gutters, and hidden ice that is forming underneath the snow and shingles.  Eventually water cannot run off the roof and pressure builds up enough for water to flow backwards.  Most roofing material it designed to work with gravity; they are layered so that as water runs down from the top it works its way down shingle by shingle until it hits the gutter; the edge of the material as well as the nail holes are covered by the unpenetrated surface of the layer above it. All bets are off though if water goes the other way such as with strong winds or ice dams.

If your roof was recently redone (or you have a new house) your contractor should have put a product on called ice and water shield.  Now this stuff is great, it is self sealing, so even nail holes do not leak water. Local codes vary, but in general any roofing construction done recently should have about 6 feet of shield on it; the codes typically require the contractor put an extra two feet beyond (above) where your outside wall meets the roof.  Since they come in three foot rolls, this tends to mean that contractors lay out 2 rows of it to meet the minimum requirement.  So you may ask, "why don't we just put that on the whole house?" The answer is simple, money.  First off, this material is very expensive and would be cost prohibitive to put on your entire house; that is not to say this is not done - some examples would be shallow pitch dormers, or locations with driving force winds, or other areas susceptible to roof leakage.  The other reason is that you are not solving the underlying problem here - you are wasting heat, that should be keeping you comfortable, and paying to heat the snow on your roof instead.  You have to solve the problem with air leaks, even if you keep the water from coming in.

Here is the real kicker about why it happens;  you may feel like you've never had the problem before and "why all of the sudden is it happening to me this winter?"  You may be surprised to find out that you've been having ice damming problems every year but you haven't seen the problem show up inside your living space.  When the water comes in through the roof it is getting soaked up by your insulation and drywall material first, after that becomes saturated is when you see it in the house. Now the worse part about this is that when your insulation becomes wet it is no longer effective and permanently destroyed; so each year your problem gets slightly worse and worse as the damage is silently being done behind your walls until it works its way to being a visible problem.

The right now solution

Since water is leaking in your house as we speak, let's first talk about how to slow or stop the water from coming in until you can fix the problem permanently.  Now I will preface this by saying every contractor has their own strong opinion on these methods and typically will naysay everything but calling them in to fix the problem.  I will try to present all of the home remedies here and let you know the good and bad of each type.  One thing you should never do is get on a ladder or on the roof and start chipping away at the ice with a hammer or pick.  This is bad, bad, bad.  Standing on a ladder is scary enough in the winter but swinging your body to use the tool while having large chunks of ice fall at you is asking for trouble. Additionally, you aren't really solving the problem, the visible ice isn't the only culprit, and you are likely going to cause damage to your roof and gutters in the process. So, here are some ways that you can help your problem and dry out your house:

(Note: Some of this work is dangerous, and following this article is at your own risk. Please consult a local skilled professional for solutions available in your area)


1) Get a roof-rake (or get a shared one for the neighborhood) and get the snow off of your roof, especially the north side of your house.


This is the number one thing to do.  As previously mentioned the water is coming from melting snow, if you remove the snow, you remove the source and your house will likely get better just from that. If it snows again, get the snow off right away, let the sun get a chance to warm up your roof from the outside and melt the remaining hidden ice away.

Here is where it starts to get controversial:

2) Take some old pantyhose and fill them with rock salt (ice-melt) and tie them off. Place each 'package' perpendicular to your gutter spaced about 18" apart, and slightly hanging over the edge of the roof 


  • This method is typically very effective and quickly removes the ice
  • It is a low-tech, low cost solution
  • It is easy for any home-owner to do (minus the ladder in winter part)
  • Each package lasts for about 3 days before it has to be "recharged"


  • Some types of salt cause discoloration to your roofing or oxidation of aluminum gutters
  • Some types of salt can cause root damage to any vegetation in the area of run-off
  • You do have to climb up on a ladder in winter, which is dangerous, but not as dangerous as having chunks of ice flying at you while you are up there


To minimize the discoloration and damage to vegetation, consult with your local hardware/ lawn and garden store for a product that is not likely to cause as many issues.  Some folks have used Urea fertilizer to achieve a similar result, which in moderation should minimize those negative effects to the roof and lawn.  One thing to keep in mind that the gentler products will also tend to require warmer weather to work vs. say CaCl salt that will work down to -25 deg F.  With that said, your problem is likely on the "warmer" days anyway so if you have to wait for it to hit 20 degrees, that shouldn't be a deal breaker.

3) Go to a hardware store and buy some heat-wire



  • If installed properly it is moderately effective
  • Doesn't require refilling/recharging, just feed it electricity
  • If installed properly you shouldn't cause any damage or discoloration to your roof



  • It can be difficult to get it installed correctly; if you don't follow the instructions it may not be effective at all
  • I am never really a fan of electricity and water at the same time, though this can be safe if utilizing the proper equipment in the installation
  • It gets in the way of roof-raking; that breaks the cardinal rule, get rid of the snow/source!


There are both permanent and temporary heat-wires.  The permanent type clip or tape to your roof and gutters and use a low voltage system.  These systems are more complex with transformers and controllers but also tend to be fairly effective when installed properly.  The temporary type plug directly into an extension chord and you just place it in the problem spots to try and get a let up in the ice build up.  In either case, it is good to keep in mind that this method is not used to get rid of the ice, it is used to carve small channels in the ice that give the built up water a place to exit. The heat-wires are similar to the gentler salt products in that they tend to only work if the temperature is above 20 degrees F. 

The right solution

So now that we've (hopefully) gotten your urgent leak under control, let's talk about permanent fixes to ice damming.

 First though I want to point out again, that the damage done from the ice dam is not just the superficial damage you see, it likely damaged your insulation in your attic and walls and means your problem will likely be worse next time you get similar weather conditions at your house.  Make sure that if you are filing an insurance claim you search your area for a building performance expert that can be your consultant and fight for you with the insurance company.  Insurance companies are reluctant as best to pay out just for the visible damage, so unless you have an expert that can vouch for you, you will be paying that deductible and the increased premium while only receiving a fraction of the value in damages. In our area we do this service for free and send either an AEE Certified Energy Manager (commercial properties) or a BPI Certified Professional (residential). 

Now that we have that said, lets go onto keeping your house ice-dam proof...or at least making your house very unlikely to ice up...

First off I will say it again, keep that snow off your roof!  If there is no standing water on your roof there is no ice buildup and there is no leaking.  Now onto the more technical solutions.

The problem lies in air-leaks and insulation. In some houses this is an easier fix than others.  If your attic has enough space for you to crawl all the way from the soffit/eave to the ridge with no walls or structures blocking you in the middle, you likely have enough room to implement lower tech solutions.  Simply find all air leaks from your conditioned space into the attic (attic access hatch,  recessed lights, HVAC equipment, etc.), and seal them up with many of the insulating and sealing products available on the market.  You then follow up with as much insulation as you can fit without compressing it at all... compressing insulation reduces its R-value. It needs to lay flat and be as continuous as possible; air can travel around 6-8" laterally through any gap in insulation.  This means that if you have one gap in laying down your insulation you can loose nearly the full insulating value of it for half the width of it! One final note, do not get the insulation wet. As soon as the insulation is exposed to water it is no longer considered usable.

Before I continue, here are some images to help you visualize what I am about to talk about.


Roof DiagramAir Leaks, Copyright EnergyStar


The other key is to identify how your roof is venting; you should have a combination of soffit/eave vents with gable and ridge venting.  The venting must be sufficient to comply with BPI standards that identify net free area requirements.  This venting should be balanced to have the appropriate airflow in each area of the general your balancing should have at least 50% from soffit vents. Make sure when you insulate you do not block this venting! This venting keeps your roof deck at outside temperatures... this keeps the snow from melting unless it is warm enough to melt without the heat of your house contributing, it also keeps your roof from overheating in the summer - both are very important! This also keeps moisture from building up in your attic that would otherwise cause mold or other health issues, along with damage to your insulation.

Sounds easy right?  Sometimes it can be, but sometimes houses are a lot more difficult.  Sometimes you cannot reach all areas to get regular batting or blown in insulation in place, in these cases the pros will have a few tools in their belt but one of the most common is pour in place foam.  Its a two part foam that gets mixed and poured right into the rafter bay so that gravity can do its work and spread it out before it dries. 

In other situations you may not have enough space at all.  A common house with problems in New England is the Cape style home.  Because the attic has been converted to rooms with that common slanted ceiling, trying to maximize room space, there is no space for insulation.  We like to get our customers to R-49 and above, code varies by location but tends to be around R-39; the problem is that traditional batting is about R-3 per inch and the space between your roof and your ceiling is typically less than 8".  This means that with no venting you could potentially reach R-24 at best.  In these situations we have to go more high-tech.  In these cases we use a combination of many different tactics, one is called a "flash and fill" where we put in venting channels followed by a layer of sealing close cell foam right against the roof decking, followed by open cell foam or batting.  If we can, we then will follow up by taking up a little bit of the space in your room with rigid foam sandwiched between the sheetrock and the rafters.  This addresses two problems... it gets us more space, and it insulates the wood rafters from the room which don't have a great R-value. With this combination we can typically get most houses up to at least local code, if not more.

A more expensive option is similar to above but instead fills the whole cavity with closed cell foam; with this solution plus the rigid foam in an 8" rafter bay we could be looking at getting you to over R-50! 

Spray Foam Bottom Up
Spray Foam Bottom Up


The most optimal method is almost identical to above but needs to be done when you do you roof or it is not feasible.  Instead of a bottom up approach, we do a top down approach.  We leave the inside of your house alone and we spray in foam after your roofing material is removed. We then add the rigid insulation to the outside of your house sandwiched between the roofing material and the deck.


Spray Foam Top Down
Spray Foam Top Down


Because there are so many tips and tricks and subtleties (fiberglass vs mineral wool, face vs. unfaced, closed cell vs. open cell, etc.) as well as potential health hazards working with these materials, we do recommend getting this job done by a professional, especially the more complex attic spaces.  This will ensure you get the best bang for your buck.  Another reason to call a pro is that even doing this yourself can get fairly expensive quickly; however, the pros have access to rebates, grants, and financing programs available through local, state, or federal funding.  In some areas you may even get 0% financing subsidized by your local green bank (in our area it is Energize CT) - the great thing about these programs is that they higher technical reviewers to review every project to ensure you are not getting ripped off by your contractor.  The typical rule for these programs is that your monthly loan cost is less than how much you will save on your monthly utility payment - or you have a 'savings to investment ratio' greater than 1.

Finally, no matter if you do this yourself or get it done by a pro, make sure that you get your combustion equipment tested before and after you change your building envelope this drastically.  This is critical to the health and longevity of your equipment and the health and safety of your family.  This equipment requires oxygen from your house to operate; by sealing up a house that used to 'breathe' may cause poor operation and carbon monoxide build up in your house.  We may find that following this your equipment needs an extra fresh air source to keep you and your loved ones safe while also protecting the longevity of your furnace, hot water heater, etc. 

So, now you know how its done.  For more information, for a free in-home estimate, or to learn how we can help you with your insurance claims, call us or e-mail us now!

Thanks for reading!


Jason A. Kane, BPI Certified Professional

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