Yours is a very common concern. Resolving ice-damming can require a combination of remedies specific, depending on the circumstances. For example, some homes may experience ice damming once in twenty years, resulting from a specific weather event. Other homes have repeated problems annually, which typically relate to interior insulation and air leakage causes.

On the roof, ice and water shield membrane should be installed at all roof eaves areas and it should be applied so that it extends at least 24 inches inside the heated wall (exterior wall). This may involve multiple courses up the roof, depending on the width of your overhangs and the roof's pitch.

The same membrane can be applied around skylights, valleys and areas prone to collect snow in winter.

Roof heating cables can be applied at roof eaves, valleys, gutter systems and inside downpipes to help limit ice formation.

Roof slopes less than 4/12 pitch should have ice shield coverage over the entire roof surface. Uneven roof sheathing with dips or hollows should be corrected.

Ventilation must be in place and free flowing to include soffit areas for intake and roof vents or ridge vents (if vaulted ceiling) to mitigate excessive heat build up and humidity in attic spaces.

Inside the home, testing may be necessary to determine air leakage points:

• the top plates of walls where they adjoin the roof structure
• broken or non-existent vapour barriers or vapour retarders (exterior walls)
• insufficient insulation levels
• pot lights (which radiate excessive heat into attics or soffits)
• incorrect dew points causing winter leaks under flat roofs
• poor structural design
• improperly vented bathroom & kitchen exhausts.

Please note: No building professional, including engineers, can provide an iron-clad guarantee against ice damming. All one can do is address ice damming conditions with the appropriate remedial efforts.

If you are considering roof replacement and want to limit the potential for ice damming, you can select products like laminate shingles (no cut-outs between tabs) or alternative coverings which serve to further mitigate such perils.

If you would like to know more, you can order an inspection. Learn more about the benefits and pricing for a roof inspection.

Learn more about ice damming from Certainteed, a valued Avenue Road Roofing supplier since 1990.