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What Ice Dams Really Do to Your Roof (And How to Stop Them in NJ)

29October 2025

“That beautiful curtain of icicles? It might be hiding a roof disaster in the making.”

Ice dams are more than just pretty winter damage—they’re a serious threat to your roof, attic, and home structure. In New Jersey, with our freeze-thaw cycles and variable snowfall, ice dams are a real seasonal risk. This article explains:

  • How ice dams form (and why NJ homes are vulnerable)

  • The types of damage ice dams can cause

  • Proven strategies to prevent them

  • What to do if an ice dam is already forming

  • How T.A. Hughes Roofing tackles ice-dam risk for South Jersey homes

Let’s dig in.

1. What Is an Ice Dam? The Science Behind It

An ice dam is a ridge or barrier of ice that forms along the edge of a roof (the eaves) that traps melting snow behind it. This trapped water then backs up under the shingles and can leak into the attic or walls. Wikipedia

How Ice Dams Develop

  1. Snow accumulates on your roof during a storm.

  2. Heat from inside the house or a warm roof surface causes the snow to melt.

  3. Melted water flows downward, but when it reaches colder parts of the roof (usually at the eaves), it refreezes.

  4. Over time, the frozen edge grows, forming a dam that prevents further drainage—causing water to pool behind it and potentially leak inward.

In NJ, temperature swings are common. One day it’s above freezing; the next day it drops. Those freeze-thaw cycles repeatedly melt and refreeze snow, making ice dams more likely.

2. Damage Ice Dams Cause (And Why You Shouldn’t Ignore Them)

Ice dams aren’t just a cosmetic nuisance—they cause real, serious damage:

Shingle & Roof Surface Damage

  • The pressure from pooled water can lift, crack, or dislodge shingles

  • Water may penetrate the underlayment

  • Repeated freeze-thaw cycles cause micro-cracks in roof materials

Interior & Structural Damage

  • Water can leak into attic insulation, wetting it and reducing its R-value

  • It can drip through to ceilings, walls, or insulation, causing stains, mold, or rot

  • Over time, wood decking or rafters can warp or degrade

Gutter & Fascia Damage

  • The weight of ice and snow can pull gutters away or bend them

  • Overflowing water may rot fascia boards or damage siding

Energy Loss & Heating Costs

  • A leaky roof or compromised insulation increases heating bills

  • Moisture in insulation reduces its efficiency

Real-Life NJ Example

In one South Jersey case, T.A. Hughes was called after a late winter thaw. The homeowner had water stains on upstairs ceilings. Our inspection revealed that an ice dam had formed, forced water under the shingles, soaked the attic insulation, and rotted roof sheathing. Repair involved replacing sheathing, insulating properly, and installing an ice & water shield system.

3. Why NJ Homes Are at High Risk

Climate & Temperature Patterns

  • NJ sees frequent freeze-thaw cycles in winter

  • Snow accumulation followed by sunny days or warm afternoons accelerates melt/refreeze

Older Construction & Insulation Deficits

  • Many NJ homes (especially built decades ago) lack modern attic insulation or proper ventilation

  • Roofs may have evolved over time with mixed materials or additions

Roof Geometry & Design

  • Roofs with multiple slopes, valleys, dormers, or overhangs create cold traps

  • Complex rooflines harbor snow and ice

Coastal Humidity & Ice Load

  • In parts of South Jersey near rivers or coasts, humidity and wet snow can contribute to heavier ice load

4. How to Prevent Ice Dams in Your NJ Home

Preventing ice dams is about controlling the root causes—temperature differentials, heat escape, and blocked drainage.

Improve Attic Insulation & Air Sealing

  • Seal gaps around pipes, attic hatches, lights, ducts

  • Add insulation to meet or exceed recommended R-values

  • Prevent heat from leaking into the attic, which melts snow above

Ensure Proper Ventilation

  • Balance intake (soffit vents) and exhaust (ridge vents)

  • Promote cold air flow along the underside of the roof deck

  • This keeps your roof surface closer to outside temperature and prevents melting above cold eaves

Use Ice & Water Barrier / Underlayment

  • Install ice & water shield under the first 3–6 feet of roof edges

  • Use high-quality, self-sealing underlayment, especially in valleys

Clean Gutters & Maintain Drainage

  • Clear gutters of leaves and debris before winter

  • Ensure downspouts direct water away from the foundation

  • Blocked gutters contribute to ice accumulation at eaves

Snow Removal: Roof Rakes

  • After heavy snow, use a roof rake to safely remove snow from roof edge (ground-level use preferred)

  • Less snow on the roof = less meltwater to refreeze

Deicing Cables / Heat Cables (Optional in Problem Zones)

  • Install electric heat cables along eaves and gutters

  • Zig-zag or straight run depending on roof design

  • Use as a backup rather than a primary solution

5. What to Do When an Ice Dam Is Forming

If you detect signs (icicles, water stains, pooling snow) act quickly:

  • Remove snow with a roof rake (don’t climb onto the roof)

  • Use calcium chloride in a sock or strip across the ice dam (not rock salt) to melt a channel

  • Avoid breaking or chiseling ice (can damage shingles)

  • Call professionals for steamer removal or safe intervention

A good reference for safe removal techniques: This Old House suggests using calcium chloride or steamers rather than brute force. ThisOldHouse

6. FAQs

Do ice dams always cause leaks?
Not always—but they often lead to water intrusion if the underlayment or shingles are compromised.

How much does ice dam damage cost to repair?
It depends—removing ice can cost a few hundred, but interior repairs, sheathing replacement, and insulation fixes can run into thousands.

Are gutter guards helpful against ice dams?
They help with leaf/debris blockage, but they don’t solve heat loss. They’re part of the package, not the entire fix.

Will insurance cover ice dam damage?
Many homeowner policies cover sudden water damage, but coverage for ice dam prevention or neglect is often excluded. Always check your policy.

7. How T.A. Hughes Roofing Solves Ice Dam Problems in South Jersey

At T.A. Hughes, we take a multi-layered approach:

  1. Thermal inspections to detect heat loss zones

  2. Air sealing & insulation upgrades in attics

  3. Code‑compliant ventilation installations

  4. Ice & water shield placement during re-roofs

  5. Snow removal services and emergency response

  6. Heat cable installation (if needed) in vulnerable locales

We guarantee our solutions will resist ice dam formation and protect your home from winter damage in Burlington, Camden, and Gloucester Counties.

📞 Call us today to schedule your winter roof assessment before the first freeze at (856) 467‑1645 or contact us online.