All About Homes Blog

Ice Damming & Gutter Heating Systems

Wednesday, January 6, 2010 by Administrator

Happy New Year! I hope you are all recovering from a fun but relaxing holiday season. I know I'm glad to be getting back into the routine.

Today I thought I'd talk about ice damming and heating coils for your gutters. We're supposed to get a doozy of a storm starting tonight. Heavy snow and cold temperatures are sure to bring us some lovely (but dangerous) icicles throughout the city.

So here's what causes ice damming - it's very simple, but can be very problematic.
- It snows (a lot lately) here in Chicago! I know - you just can't believe how helpful this info is!
- After it snows, it often stays really really cold (again, so helpful, I know)
- Most of us are lucky enough to live in well heated homes
- Many of us are not lucky enough to have well insulated homes
- If there's a lack of insulation (and/or ventilation) between the ceilings and the roof, then heat rises from the home and melts the snow on the roof.
- As the melting snow runs towards the gutters it re-freezes where there is no more heat loss from inside the home - usually at the soffit overhang, over the back porches or at the gutters.
- As the cycle repeats itself ice dams build up at the gutters and the problems begin...

Here's what a roof should look like in the winter. The roof is covered with snow, no icicles...lovely!

Ice damming - Chevalier 002.JPG

Here's what a roof shouldn't look like in winter. Melted snow and icicles...not so lovely!

Ice damming - Chevalier 004.JPG

These photos were taken on the same day in the same neighborhood last year. Sadly, I get great enjoyment out of driving around during the winter and looking at people's roofs and thinking "ah, good insulation, bad insulation". Wow - and I wonder why I'm single! :-)

For you analytical types, here is a drawing. This shows a pitched roof but it's the same for flat roofs. The difference is that the ice will start to form on the entire back porch roof instead of just at the gutters.


Here are some of the problems associated with ice damming:
- Dangerous icicles fall and mess up your hair
- Dripping icicles make sidewalks below like the 'slip-n-slides' we loved as kids but loath as adults
- Icicles are heavy - they bend, twist and even break gutters
- Water starts to lift up roofing materials and begins to leak into the home
- Once the water is in the home all sorts of fun begins, including but not limited to, ruined attic insulation, mold growth on roof sheathing and rafters, leaking into living areas, mold growth in living areas, soffit wood rot etc.

So hopefully you can see what kind of trouble those beautiful but nasty icicles can get you into. I can't even begin to tell you how many attic hatches I've opened up over the years and found mold growth on the roof sheathing that was clearly caused by ice damming. Sadly, the home owners had no idea. Trust me; it's a tough day when your buyer's home inspector breaks the news of an attic full of mold.

So, let's talk about prevention...

Unfinished Attics and General Roofing Info: (I know there are several new insulation technologies available but I'm just going to address the traditional method here for now.)
- The first thing to remember is that attics should be the SAME temperature as the outdoors. If it is too warm in the attic during the winter then ice damming will occur.
- An attic will be appropriately cold if it is properly vented and properly insulated.
- Venting can be done in many ways - ridge and soffit vents, roof and soffit vents, gable vents etc. There just has to be good air flow in the attic.
- Insulation, more often than not, seems to be where the problems begin. In Chicagoland an insulation value of R-38 is the recommended level! Rarely do I see this level achieved. Insulation should be in the attic floor as opposed to between the rafters (wherever possible). We'll talk about insulating between rafters on another day. Old insulation compresses and becomes useless.
- Install a membrane between the roofing shingles and the sub-roof that runs at least 3 feet up the roof from the gutter. This will prevent moisture from leaking inside the home/attic if ice damming does occur.
- Make sure that gutters are properly sized and pitched. Keep gutters free of debris. Make sure that downspouts are not blocked or leaking. Make sure there is at least 1 downspout for every 30 feet of gutter.

If an attic is well vented and well insulated, ice damming should not be an issue.

Vaulted Ceilings/Finished Attics/Inaccessible Attics/Flat Roofs:
These are harder to insulate and ventilate - unless you have nothing better to do than rip out your ceilings!

So, here's a good alternative (although not as environmentally friendly as adding insulation). This solution can also be used in homes with attics as well if for whatever reason it is not preferable to insulate and ventilate.

Electric Gutter Heating Systems:
Electric heating coils or heating pads can be added where the ice damming is occurring. These systems can be very effective and safe if properly installed. The coils keep the melting snow from re-freezing at the gutters and keep the gutters and downspouts clear of ice.

But as with most things, it's all about the installation. If these systems are not properly installed they can be fire hazards. So ice damming is bad, but burning down your house, is waaaay worse!

Here's what you should know:
- Hire a professional to do the installation - too many homeowners have fallen off roofs, damaged their roofs and started fires doing this themselves! It's just NOT worth it. BTW - the fire at Holy Name Cathedral last winter was caused by a roof heating system!
- My recommendation for a good installer in the area is Nelson Roofing - see the resources page.
- The systems should NEVER be installed using extension cords. An electrical box with a GFI protected outlet needs to be installed at the gutter area. The wiring needs to run in solid metal conduit directly from the main electrical panel.
- The roof can easily be damaged if the coils are not attached properly. Leaky roofs aren't much fun either.
- Some systems have to be turned on by the home owner and some have sensors. Obviously the automatic systems are more expensive, but if you forget to turn on the coils before it snows, it's too late. Also, if you forget to turn them off, they can burn out.
- Here's a website that shows how these systems should be installed. Check it out - it's not as simple as it may seem. Hire a professional!

Overall, the main point...if you have icicles forming on your home...don't ignore them. Prevention is always your best option!

Hope this was helpful and thanks for reading!