What Causes Snow to Stay on the Roof if It's Insulated?

Winter Roof Stress

• Cold, snow and ice put a burden on house roofing. Freezing and melting mean heavy exposure to moisture and weight on various parts of the roof as accumulated snow melts or shifts. One of the most common problems homeowners experience is the formation of ice dams at the roof edge. Melted snow refreezes, and layers collect on top of each other. The weight of an ice dam can rip off canopies, porch roofs and gutters as well as sections of roofing. Damage can leave interior spaces open to damage and leakage as winter continues, preventing immediate repair.

Insulating for Protection

• One of the best defenses against winter water damage is good insulation in the attic or crawlspaces under the roof. Home improvement centers or contractors can advise on the R-value (heat diffusion resistance) and thickness of insulation needed to keep indoor heat from escaping to warm the underside of the roof.

Additional Strategies

• Insulating the attic floor is as important as placing a heat barrier on the underside of the roof surface. This process may be complicated by electrical outlets, fans and vents, all of which are sources for additional heat-escape into the attic. Insulating these open spaces between the attic floor and downstairs ceilings may require some ingenuity, especially when dealing with bathroom exhaust fans and recessed lighting. Each house will present different, and perhaps unpredictable, challenges, but redirecting hot humid air escaping into the attic through ceilings is necessary to protect your roof. Plumbing supply centers may offer solutions to many of these problems.

Persistence and Monitoring

• Once you have blocked all possible avenues for hot air collecting under the roof, monitor your progress with each subsequent storm. Areas that still drip or collect icycles may need further insulation or venting. Resist the temptation to remove snow from the roof by hand or with hot water. Do not use snow-melt or other chemical removers, which can further damage your roof surface. Winter sun may melt snow, but watch for even melting, evaporation and runoff.