Snowy roofs across the Delaware Valley make a pretty winter scene, but melting roof snow can form dangerous ice dams. Preventative measures, like putting de-icing cables in the gutters or physically breaking the ice, only treats the symptoms. Attic insulation cures the problem. Snows melts on a cold day because your heated house is emitting warm air through the roof. Instead of battling ice dams all winter, learn how to prevent ice dams on a roof once and for all.

How to Prevent Ice Dams on a Roof

Select your insulation product for the attic. You need to achieve a 12-inch thick layer.

For fiberglass batts:

1. Seal gaps in the ceiling around plumbing ventilation pipes and electrical wires with expanding foam spray.
2. Measure length of channels between ceiling joists.
3. Put on a dust mask to ensure you don’t inhale fiberglass fibers.
4. Wear work gloves because the batts can cause skin irritation.
5. Cut fiberglass batts to size with insulation knife.
6. Lay the insulation between the joists with the paper vapor seal side on the bottom.
7. Once the joists have been filled with batts, add another layer of batts across the floor joists.

For cellulose insulation:

1. Spray the expanding foam around ceiling gaps to seal heat into the attic as much as possible.
2. Make marks throughout attic structure 12 inches from ceiling. This creates a guide so that you know when insulation is deep enough.
3. Choose a place outside to set up the blower below an attic window or vent.
4. Put on a face mask and crumble loose insulation into the blower’s hopper.
5. Run the hose up to the attic.
6. Position yourself in a central location near the attic access door.
7. Blow insulation into the edges first and gradually fill the whole space.