Our top floor is finished/heated. How to prevent ice dams

Ok gentilmen , lets talk ice dams. First and foremost, what causes an ice dam to form anyway. Heat trapped in an attic, either from heat loss from the house or sun beating on the roof, cannot escape quickly and melts snow on the roof. This water drains to the bottom of the roof where it runs across a cold edge and freezes. The overhang of your roof (soffit area) is typically not over a heated area and tends to be very cold, much colder that the rest of the roof. Even with a well insulated ceiling and good ventilation ice dams will form if conditions are right. This is where the old saying,"an ounce of prevention is worth a pound of cure" rings true. Any time you have a heavy snow load on your roof followed by some moderate temps or sunny days, some natural melting is going to occur, especially if the ridge vents are buried in snow. Sun hitting the gable ends will heat up the attic a bit too. Many times the ice dam starts in the gutters then bridges over to the roof edge and starts it's way up. Once it starts, there is now way to stop it unless the source of water building it is taken away. The only way to deprive the ice dam of more water is to REMOVE THE SNOW FROM THE ROOF AND MAKE AN EXIT FOR ANY REMAINING WATER TO DRAIN. This is why it is so important to use a roof rake soon after a snowfall to remove several feet of snow from the edge of the roof. With the snow removed, you can see if a dam is starting and can address it quickly while it is small and easy to treat. Other things to consider may include, if you live in an area where your ridge vent commonly is covered in snow, add a gable end vent on both sides of the house and be sure the soffit vents are equipped with "proper vent panels" inside and that they are not blocked by insulation. Always use a minimum of 6 feet of Grace ice and water shield, or if you want a good insurance policy against leaks, cover the entire roof with Grace before shingling. This may cost a bit more up front, but pays for itself in the long run. Maximize your attic insulation. Take a good look at your gutters and consider lowering them if they are too close to the drip edge where ice dams begin. There is no one thing that will prevent ice dams, but if you look at all the preventions at your disposal, dealing with them will be a lot easier. Sorry for preaching guys, but I give this same speel to many customers every year when water is leaking in their homes and they are shelling out big bucks for repairs. Two years ago here in Maine, the huge snowfalls and subsiquint ice dam problems prompted homeowners insurance companies to send out letters telling policy holders that they would not cover a second loss if these precautions were not met.

Electric cables can be fixed there very well. Let's say we use 2 mm thick cables with low wattage (10 W/m).

Firstly you cut 2 mm wide and 3 mm deep cuts to the bottom side of your steps (using a hand circular saw). They should be parallel going from side to side. Put silicone and cables into the cut doing S bends, they should just fit in there. Cover the cuts with silicone to close them against pollution & weather.
Cut one cut for thermal sensor 2 cm next to the cable cut. It should be in a "thermally representative" place. Put the thermal sensor in it and cover it with silicone.
Do the wiring: thermal sensor and cables to thermostat and thermostat to the power line (via curcuit break).

I have in-floor radiant cables installed in cuts in EPS mats under the laminate flooring. There is a thermostat with an in-floor thermal sensor which I set to about 20°C. It works well and feels even better. They say cables must be embedded in a couple inches of cement, sand, or asphalt because the flooring can be overheated. That's why the low wattage (combined with wood stair tread).

But - will it do the job? Sure, because if it's only below freezing, it's enough to raise the temperature a bit to unfreeze. If it's rather cold, it's probably not freezing rain in the air (I don't know your climate).

Main pros:

• You can decide how dense the cuts are to each other to decide the total heating power. I'd say 80 W/m² should do.
• Silicone covering the cables (above and under) will protect them from any damage and they will easily exceed the expected lifetime. And the surface of the wood will be stay closed against weather.
• You set the thermostat to the required temperature (+3°C maybe). You can even turn it off or buy a thermostat with a programmable clock to be used at night.
• Much of the work can be done by yourself and the materials needed aren't expensive too. Even with 100 m of cable and a programmable thermostat you won't exceed the limit.

Some cons:

• Cutting from side to side weakens your steps very little or not at all.
• You'll have to fiddle with bending and fastening the cables at each turn, because they have some minimal circumference of bend (5 cm maybe). You can let them just bend freely off the cut, but cover them with silicone too. Or cut several short cuts of circular shape.
• You might decide to use Thermal Silicone to get even better heat transfer. But I don't think it's needed.

One more thought: pipeline protection cables have a built-in thermostats at certain places. But they are rather thick (9 mm) and expensive.