SHREWSBURY, Massachusetts – Because of the huge amount of snow we had the winter of 2010, many homeowners who never had an issue before, suddenly became intimately familiar with the ice dams, roof rakes, and all the rest of the things that seem to follow just after that gorgeous white stuff comes to town. Today, I want to chat a bit about what ice dams are, what causes them, how to prevent them, and what to do if they occur.
Simply put, ice dams themselves occur when snow and ice build up at the edge of your roof, and they are caused quite simply by a lack of ventilation in the attic. As you view your attic from the side, it looks like a giant triangle. Physics dictate that hot air rises, and so were it not for your ridge vent allowing this warm air to escape, the upper part of your attic becomes warmer than the lower part. If the upper part of the attic gets above 32 degrees, the snow on the upper part of the roof melts, turns to water, and rolls down the roof until it reaches an area that’s below 32 degrees. When it hits that colder area, it freezes into a block of ice. Now the trouble starts. With this ice dam in place, preventing water from flowing off the roof, future water pouring down from this upper section now hits the dam and back up underneath the shingles, flooding the attic, dripping down the walls and making a huge mess.
1. Preventing ice dams from forming. There are several critical things that can be done to prevent the formation of ice dams. First, is to add ventilation in the attic. If you don’t already have ridge and soffit vents, look at this spring as a time to add them. If your home is older, and adding soffit and ridge vents is too big of an expense, then consider adding vents in some other way, such as cutting in a vent at each of the gable ends of the home. This added ventilation has one singular goal, which is to ensure that all heights within the attic are the same temperature. It may seem counterproductive to think that making the attic colder is a good idea, but it truly is. Ideally, if the whole attic were the same temperature as the outside, there would be no ice dams.
2. Use a roof rake to remove snow from the roof the day after a storm, and before it freezes up. You’re not there to chip away at existing ice with a rake. This will usually cause far more damage than it stops. If you don’t already have a roof rake, it’s not easy to find one this time of year. Try Home Depot, Lowes, and all of the other major stores, but your best bet might be to buy it on line and have it shipped to you. If your roof is too tall to rake off all of the snow, at least try to get to the lowest few feet near the endue, as this is where ice dams tend to form.
3. If you have a regular ice dam issue, as I did, consider installing heating cables in the particular area that is most susceptible and this will go a long way towards solving all of your problems. Just remember to turn them on and off only as needed, so they don’t waste electricity or cause other issues.
4. When you have your roof redone the next time, install a rubber ice and water barrier on the lower 3-6 feet of your roof, before you put on the new shingles. That extra layer of protection under the shingles is a huge help.
Ok, so there are four ways to prevent ice dams from occurring. Now the question is what to do if you failed to take precautions, and wound up with an ice dam. Well first, what “not to do” is to climb up on a ladder with an ice pick and try to chip it away. It’s never going to be successful, and you will no doubt cause further damage.
Here are a few tricks that may be helpful.
1. First and foremost, you need to cool the attic to stop the flow of water down the roof. If you have roof vents that are blocked, you need to clear them with a roof rake. If you have windows up there, crack them open to let cold air in. Make sure if you’re working up in the attic, you keep the staircase, door or hatchway closed, to keep more heat from coming up.
2. To melt the ice dam, there are a few tricks that people have come up with, which have worked well. Go out and buy some Calcium Chloride ice melting compound, and a pair of ladies panty hose. (Now there’s a shopping trip and a half!) Fill one leg of the stocking with the ice melt compound and tie it off. Use a pole, or roof rake to raise the stocking up onto the roof, in the area of the ice dam, but partially hanging off the roof, and leave it there. In a short time, the CaCl will leach out of the stocking onto the roof and begin to melt the ice. Avoid trying to throw the ice melt mixture up onto the roof. Most likely, you won’t melt the ice dam, and your efforts will cause more melting “above” the dam, which will cause more water to flow down and into your home.
3. One technique I came up with a few years ago in the middle of such an emergency, was to go out and buy a roof heating cable, loop it around the end of the roof rake, and then raise it up and lay it on the area where the ice dam ice. I plugged it in, and left it there overnight, and by morning the ice dam was gone.
4. Once you have a process in place to melt the dam, you now can worry about what’s happened inside. If you work quickly, you may even be able to avoid painting. Mix a 1:1 batch of bleach and water, and with a sponge, dab the bleach mixture on the wet spot. The bleach will tend to get rid of any staining. You won’t know, however, until it’s all dry, but worst case a little paint will do the trick.
Hopefully those tips are helpful. If you have any others, by all means send them over and we’ll add them to the article.