The do it yourself resource for homeowners from home improvement professionals.

How to Prevent Ice Dams on a Roof

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.

Tools & Materials

You can choose fiberglass batts or loose cellulose insulation. Depending on your choice, the tools and materials you need will vary. If you choose to blow in cellulose, you can rent the insulation blower from a building supply store.
  • Dust face mask
  • Work gloves
  • Can of expanding spray foam fire-blocking insulation
  • Insulation knife for cutting fiberglass batts
  • Measuring tape
  • Insulation blower for cellulose

Professional Roof Repairs and Ice Dam Removal Services

The roof repair experts at PJ Fitzpatrick can remove ice dams once they form and fix water-damaged roofs. We can also address problems like inadequate roof ventilation that is contributing to ice dam formation. If your gutters have been damaged from ice dams, we can help with the necessary repairs. Taking the time to learn how to prevent ice dams on a roof will prevent costly damage. Contact us for an estimate today.

Need help with this project?

We have trained professionals that can help. Contact us today. 1-877-246-4354

Get Free Estimate