Ice Dams | Protection - Prevention - Solutions


     What causes ice dams?                               Ice dam on dhed roof

          Poor roof design

          Blocked soffit vents

          Poorly installed attic insulation

     How do you stop ice dam leaks?

          Removing roof snow

          Install temporary  heat tape

     How do you prevent ice dams? 

          Attic and roof ventilation


Photo at right; Ice dam caused by heat loss from poorly insulated attic.


Poor Design and Ice Problems

Ice Dams and water backup leaks caused by poor roof and building design.


Poor building design is often the cause of ice dams and the resulting roof leaks. Houses are often designed with little to no overhang at the eaves of the house. Without an adequate overhang there is no room to install the needed vents at the soffit. The best soffit ventilation is usually continuous strip vents installed the length of the roof eaves. Small round plug style vents and larger louvered vents cut and installed between roof rafters can work well but are often insufficient.The house pictured below has some overhang but little space to install venting. The overhang is mostly taken up by mouldings and trim work.

Read more: Poor Design and Ice Problems


Metal Roof Ice Dam

Will a metal roof prevent ice dams?


A metal roof can reduce the leaking that occurs due to ice damming but it will not prevent ice dams from forming. In some cases it may add to the ice dam formation. A metal roof may warm up faster from solar heat gain  than an asphalt roof creating more snow melt flowing to the lower edge of the roof where it can freeze.

Read more: Metal Roof Ice Dam


Attic insulation removal causing Ice Dam

A contractor  hired to solve an ice dam problem ends up causing more harm than good.


This house was experiencing leaking in the winter after heavy snow fall due to ice dam buildup in the roof rain gutters and water backing up under the roofing. A roofing contractor installed ice and water shield along the lower edge of the roof eave and in the valley area and informed the owner that in order to reduce or prevent the formation of the ice dam more ventilation and insulation would be required in the attic.

Read more: Attic insulation removal causing Ice Dam


Porch roof vent for ice dam relief

Preventing ice dams by installing knee wall vents above porch roof.

 This past winter, the porch roof shown here was covered in snow and ice in the gutter and on the lower edge of the roof. The ice buildup was causing water to back up under the roof slate and into the interior.

Read more: Porch roof vent for ice dam relief

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