How to Prevent Ice Dams | This Old House

This Old House general contractor Tom Silva shows how to super-insulate an attic for ice dam prevention. (See below for a shopping list.)

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Tom showed several ways to get rid of existing ice dams, including tossing a paper bag filled with ice melt behind the dam. Ice melt is available at hardware stores and home centers.

Tom also suggested aiming a fan at the eaves of your roof from inside the attic, blowing cold air from the attic at the dam. This will make the roof cold and prevent the ice dam from continuing to grow.

Shopping List for How to Prevent Ice Dams:
- expanding-foam sealant [amzn.to/2Zjiled]
- closed-cell spray foam insulation [amzn.to/2KT7Zh3]

To prevent ice dams from forming, Tom installed closed-cell spray foam insulation into the roof rafter bays. A professional insulation contractor can provide this service. On this project, he worked with Anderson Insulation [andersoninsul.com/].

The spray foam they applied is Icynene MD-C-200 [icynene.com/].

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How to Prevent Ice Dams | This Old House
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