Steve writes from Spencerport, New York: "I have a new house (6 months old) it has a high hip roof with a ridge vent and soffit vents every 2 feet or so, I have icicles and ice dams forming all around the house especially in valley areas, How do I know if this is due to not enough insulation or not enough venting?"

Answer: Depending on your location you should have anywhere from 12 to 16 inches of insulation in the attic. However, insulation alone won't prevent ice damning. Proper ventilation and a properly air sealed ceiling are also important. It sounds like you may have enough ventilation so the next thing to check is the insulation level and how well that attic is sealed. Adding insulation is relatively easy but many people miss the importance of sealing all the penetrations into the attic. You should check to see that all plumbing, electrical and heating penetrations, along with any lights and ceiling fan boxes, are sealed. Sealing these can typically be done with spray foam and/or caulk.

Even when everything is done right you can still end up with some ice depending on the weather conditions.