Ok, maybe on some of these freezing cold days, or days of rain/snow/sleet, it may not seem like a wonderland, but winter in Maine does bring with it a sure sense of beauty and reminds us, Mother Nature is boss. Common themes for home inspectors this time of year are proper heating, worry about freezing pipes, insulation values, and leaking roofs.
All part of what we look for. But when it is 20 below with a wind chill, pipes that would never otherwise freeze, suddenly do. So, no matter what the conditions, remember to rake heavy snow loads off the roofs, keep your heating system maintained, insulate well where possible, but especially around pipes near outside walls, and you will find winters in Maine are more enjoyable to live with.
Since ice dams are such a hot topic this time of year, we have included some information below on this issue. Please call or email us if you would like further information.
What are they?
In a perfect world, snow and sleet that lands on your roof would melt and drain off, similar to rain. However, in the winter, a combination of factors can create a situation where large ice chunks (called dams) form near the edge of the roof. Now, this would not be a problem, except that the dams often hold water behind them, which can slowly work it’s way underneath the shingles, and find a small crack to get through into the interior of the home. Often the first time you know you have an ice dam problem is when you hear a steady drip, drip, drip, somewhere in your house, usually coming from the ceiling near an exterior wall. And once you have an ice dam, it is not easy to get rid of.
Why do they happen?
Depending on the amount of insulation in the roof and attic, and depending on the amount of air ventilation in the attic, a roof will release some amount of heat that comes from inside the home. Look at your neighbor’s roof after a snowstorm. Do you see lines or shadows on it from melting snow? That is this effect.
Snow that is on the roof will melt from this heat and drip down to the roof edge. Due to the eave overhang at the edge of the roof, the roof edge is usually cooler. When water drips onto it, it may be cold enough to freeze. This usually will happen repeatedly, depending on weather conditions, and ice will begin to form, becoming a larger and larger block or dam at the edge of the roof. As this ice builds up, it often lifts up the shingles that are at the edge of the dam, and this allows water draining from above, to get into the roof structure and eventually the interior.
Also, realize that certain home designs and certain weather events will encourage ice dam buildup. You can’t do much about the weather, but avoid homes with lots of hips and valleys or a low sloped roof if you want to avoid ice dam problems.
How can they be prevented?
If this happens to you in the winter and you want to get rid of it, then you have to find a way to get rid of the ice. This is hard to do without ruining the shingles in the process. Be careful using a tool to chip the ice as you can damage shingles with the tool. Heat tape can warm and melt the ice but be careful using heat tape in the winter because heat tape is electrified and if the end comes in contact with water, it can short out or cause a fault. Also, always be careful on any roof, especially when it could be slippery; it is not worth falling off.
To best prevent ice dams, you need to have adequate ceiling/roof insulation. R39 is now recommended and this is the equivalent of roughly 12” of fiberglass batten insulation. The better the insulation, the less heat gets lost from the interior up to the roof. This will also save on your heating bills! Also remember to insulate or seal all holes or openings in the insulation. So often, we have done an inspection and found there is an uninsulated access hatch into the attic or a bathroom fan vent in the attic; these just freely allow warm air to enter the underside of the roof, creating more chance for snow melt and ice dam buildup.
Secondly, improve the ventilation in the attic. There are many ways to do this so discuss this with a home inspector or contractor to get the best advice.
KEY POINT TO REMEMBER: Good insulation and ventilation in the attic will do the most to prevent ice dam buildup.