Ice dams are one of the most common (and costly) winter roofing problems in Central PA. Left unchecked, they can soak attic insulation, rot roof decking, and cause interior leaks—especially during freeze-thaw cycles in February.
At Equity Roofing, we’ve helped hundreds of homeowners from Harrisburg to Susquehanna Valley prevent and repair ice dam damage through smarter insulation, ventilation, and roof upgrades. As Owens Corning Platinum Preferred Contractors, we're dedicated to providing homeowners with the best solution (and education) for their roof.
In this article, you’ll learn what causes ice dams, how to spot them early, the smartest ways to prevent or fix them, and real-world examples from the field.
Clickable Table of Contents:
By the end, you’ll know exactly how to stop ice dams from forming—and how to keep your home safe and dry all winter long.
An ice dam prevents water from draining, and the backed-up meltwater can get forced under your shingles. When snow melts on the upper part of your roof (because of poor attic ventilation or insulation) and then refreezes at the colder eaves, an “ice dam” forms.
Even metal roofing isn’t safe against ice dams. They can suffer from leaks when snow gets piled in the transition from steep to low parts of the roof.
Once water breaches the roof layer, it can:
Central PA homes are particularly vulnerable. Our freeze-thaw cycles create the perfect conditions for ice dams, and many older homes lack proper insulation and ventilation to prevent them.
Large icicles, bare spots on a snowy roof, and water stains on your ceiling are common signs of ice dams. By learning to spot these indicators and checking for them regularly throughout winter, you can catch problems while they're still manageable.
| Outside Your Home | Inside Your Home |
| Large icicles on gutters or eaves | Water stains on ceilings near exterior walls |
| Visible ice ridges along the roof edge | Peeling paint or bubbling wallpaper |
| Water dripping behind gutters | Musty odors in the attic |
| Uneven snow coverage with bare spots near the roof peak | Frost on the underside of roof sheathing |
| A clear melting line partway down the roof | Damp insulation above exterior walls in the attic |
The damage often shows up first in the attic before you ever notice problems in living spaces. If you can safely access your attic, check the areas directly above your exterior walls. Look for darkened wood, which indicates past or current water intrusion.
Small icicles that form and melt quickly are usually harmless. Worry when they're large, persistent, and appear in the same spots repeatedly. If the same areas of your roof consistently develop icicles while others don't, you've identified a problem zone that needs attention.
The best way to prevent ice dams is to regularly monitor your attic, maintain clear gutters, keep your roof free of snow, and address any insulation or ventilation issues your roof may have. These measures are supposed by the Insurance Institute for Business and Home Safety, who conducted a joint study on ice dams and building codes.
Your attic temperature should match outdoor temperatures. If it's significantly warmer, heat is escaping from below. A temperature difference of more than 10 degrees indicates serious heat loss that will fuel ice dam formation.
Use these tools:
Clogged gutters worsen ice dam formation. Clean them thoroughly each fall and consider installing guards if trees surround your property. Even with guards installed, check periodically that water can flow freely. Debris sitting on top of gutter guards can still create blockages.
After heavy snowfall, use a roof rake to clear the lower 3-4 feet of your roof:
The key is removing snow before it has a chance to melt and refreeze. This is especially important after storms that dump 6 inches or more, as the weight of snow provides insulation that accelerates the melting process underneath.
To prevent ice dams in the long term, ensure your attic is properly sealed, well-insulated (R-38 to R-60), and well-ventilated with clear soffits, ridge vents, and baffles. Many homeowners accidentally block airflow paths while adding insulation, trapping heat and moisture—exactly what fuels ice dam formation.
If you already have an ice dam, avoid these mistakes:
Instead, you can take the following safe approaches:
Remember that most ice dam damage happens gradually. If you're dealing with one now and it's not actively leaking, your best move might be waiting for warmer weather and then addressing the underlying causes.
A good roofing contractor checks your ventilation system, roof deck, and insulation—not just your shingles or metal roof.
More often than not, a roofing contractor should always check your attic. A proper diagnosis of your roof requires looking at the complete system.
When homeowners see the cost of prevention measures, they often hesitate—but once you compare those costs to the repairs you'll face without them, the financial decision becomes crystal clear.
| Prevention Measure | Typical Cost | Related Repair | Typical Cost |
| Attic insulation upgrade (R-38 to R-60) | $1,500–$3,000 | Water damage repair – soaked drywall, ceilings, and insulation | $2,000–$8,000 |
| Ventilation improvements (ridge/soffit vents, baffles) | $500–$1,500 | Mold remediation – attic mold and poor air quality | $3,000–$10,000 |
| Ice-and-water shield installation (during reroof) | $500–$1,000 | Roof deck replacement – rotted decking along eaves | $5,000–$15,000 |
| Annual professional inspection | $200–$400 | Complete roof replacement – after repeated leak cycles | $8,000–$20,000 |
Spending a few thousand on prevention can save 10× that amount in long-term repair costs—and protect your home from hidden structural damage, mold, and recurring leaks.
Ice dams aren’t just cosmetic issues. They’re often the first sign of deeper problems in your roofing or attic system. And by the time water starts dripping from your ceiling, it’s already too late to avoid the damage.
If you’ve seen icicles forming in the same spots each winter, or dealt with ice dams before, now is the time to act. Your next step is to read our guide on Why Your Roofer Should Always Check Your Attic During a Roof Inspection—so you can avoid contractors who miss the real cause of ice dam damage.
At Equity Roofing, we offer comprehensive attic and roof evaluations. Our tailored solutions for Central PA’s climate include clear, honest explanations of what’s happening and why. If you have current questions about your roof, we're here to help.
Don’t wait for leaks to address your roof. Inspect your roof ahead of winter so your home stays dry, protected, and stress-free all season long.