Ice dams are caused when there is inadequate installed roofing materials, lack of ventilation and/or insulation and heavy, constant snowfall causing damage to your home.
There are some tips on preventing ice dams:
-Invest in a roof rake to carefully remove snow building up on the roof
-Install a ridge vent, soffit vents and/or roof vents/channels in the attic to circulate warm air
-Insulate attic floors and the underside of the roof
-Eliminate warm air from leaving the attic by checking for leaks around pipe openings, stair doors, light fixtures, covered soffit vents
-Speak with your contractor about setting-up a ice & shield 6+ feet from the roof edge and ensuring a adequate installed roof
-Ensure that your gutters are cleaned to allow melting snow to run through smoothly
(Prepare Your Roof for Winter; Norfolk & Dedham 2015)