A homeowner can replace their entire roof, get brand-new shingles, and still see ice dams come back the following winter.

That can be frustrating, especially when the assumption was that the old roof was causing the problem. But in many homes, the shingles themselves were never the root cause.

Ice dams often start underneath the roof—in the attic.

Here in Michigan, one of the biggest things we look at is how heat is moving from the living space into the attic, how well the home is insulated, and whether the ventilation system is actually moving that heat out.

If those underlying conditions are not corrected, you can put a beautiful new roofing system on the house and still end up with the same ice dam problem.

How Do Ice Dams Form?

Ice dams typically begin when heat from inside the home reaches the attic and warms the underside of the roof deck.

There are a couple of common reasons this happens.

The insulation may not be adequate enough to slow the transfer of heat from the home into the attic. Or the heat may be reaching the attic but not being properly moved out through the ventilation system.

Either way, the roof deck becomes warmer than it should be.

When there is snow sitting on the roof, that warmth can begin melting the snow from underneath. The melted water then travels down the roof toward the lower edge.

Once it reaches the eaves and other colder portions of the roof, the temperature can drop back below freezing.

The water freezes again.

As that process continues—melting, running down the roof, and refreezing—ice begins building up at the edge. Eventually, you have an ice dam.

That means the ice you see outside the house may actually be the result of something happening inside the attic.

Why Can Ice Dams Come Back After a Roof Replacement?

This is where homeowners can understandably get confused.

Replacing a roof addresses the roofing system itself. It gives you new underlayment, shingles, flashing, and other roofing components.

But simply installing new shingles does not automatically change what is happening underneath them.

If excessive heat is still building up in the attic because of inadequate insulation or improper ventilation, the same conditions that caused the original ice dam can still exist after the roof replacement.

We run across this when homeowners ask us to solve recurring ice dam problems.

You have to look deeper than the surface.

The question isn't just:

"Does this home need a new roof?"

It is also:

"Why is the roof getting warm enough to melt snow in the first place?"

Until you answer that question, you may only be addressing part of the problem.

Insulation Plays a Major Role

One area we look at is the home's insulation.

The goal is to reduce how much heat from the conditioned living space is reaching the attic.

If the insulation isn't adequate, heat can transfer upward too easily. That raises the temperature in the attic and can warm the roof deck above it.

Adding insulation, when necessary, helps slow down that heat transfer.

Think of it this way: we want the attic and roof deck during the winter to remain much closer to the outdoor temperature instead of allowing a large amount of heat from the house to reach the roof.

When the roof deck stays colder, the snow above it is less likely to continually melt from underneath.

But insulation is only one part of the equation.

The Attic Also Needs Proper Ventilation

If heat does reach the attic, you also need a way to move it out.

That's where ventilation comes in.

A properly designed passive attic ventilation system generally needs two sides working together:

  • Intake ventilation that allows fresh outside air into the lower portion of the roof or attic.
  • Exhaust ventilation that allows warmer air to escape near the upper portion of the roof.

One of the biggest things we pay attention to is the balance between intake and exhaust.

You don't simply add a few vents and assume the attic is properly ventilated.

There are calculations involved in determining how much ventilation the attic needs and whether there is enough intake to support the amount of exhaust.

If those components aren't working together correctly, you can still end up with unwanted heat buildup.

What If a Home Doesn't Have Enough Soffit Ventilation?

This is an important situation homeowners may not realize has a solution.

Traditionally, intake air often enters through vents in the soffits underneath the roof overhang.

But not every home has a design that makes adding or improving soffit ventilation easy.

In some situations, intake ventilation can actually be added from the rooftop itself.

There are roof-edge intake products that can be installed near the lower portion of the roof to bring fresh air into the attic. That air can then work its way upward while warmer air exits through a ridge vent or another properly designed exhaust system.

That can give us another option for correcting the ventilation system without necessarily having to tear into or completely rebuild the soffit area.

The important part isn't simply which vent is used. It's creating a system where fresh air can enter low and warmer air can leave high, with the appropriate amount of intake and exhaust for that particular attic.

A New Roof Is a Good Time to Look at the Entire System

This is one reason a roof replacement can actually be a great opportunity to address recurring ice dams—as long as you're looking at more than the shingles.

While the roof is being evaluated or replaced, we can look at things like:

  • The existing insulation
  • Attic temperatures and heat buildup
  • Available intake ventilation
  • Existing exhaust ventilation
  • Whether intake and exhaust are properly balanced
  • Whether the home's current design requires another ventilation approach

Sometimes part of the solution is increasing insulation.

Sometimes ventilation needs to be corrected.

Sometimes both need attention.

The key is figuring out why the ice dam developed before simply assuming a new roof will eliminate it.

The Same Attic Problem Can Hurt Your Roof in Summer

There's another part of this that homeowners don't always think about.

The attic doesn't stop affecting your roofing system when winter ends.

In the summertime, an attic without adequate ventilation can become extremely hot. Some of that heat comes from inside the home, but a tremendous amount can also come from outdoor temperatures and the sun heating the roofing system.

That excessive attic heat can affect the roofing materials from underneath.

It's not talked about nearly as much as leaks or ice dams, but attic temperature can have an impact on the longevity and performance of the shingles.

So good insulation and ventilation aren't just about preventing an ice dam for a few months each winter.

You're creating better conditions for the roofing system throughout the year.

Proper Attic Conditions Can Help With More Than Ice Dams

When we inspect an attic, we're looking at the bigger picture.

Poorly managed heat and moisture can contribute to several problems over time.

Depending on the home, better insulation and ventilation can help with:

  • Reducing the conditions that contribute to recurring ice dams
  • Managing excessive attic temperatures
  • Reducing moisture accumulation
  • Lowering the potential for mold-related attic issues
  • Protecting the roof deck and roofing components
  • Supporting longer-term shingle performance
  • Creating a more comfortable home

That's why I don't like looking at the shingles as an isolated product.

Your roof is part of a larger system.

If the attic isn't insulated and ventilated properly, you're asking the roofing materials above it to perform under conditions they weren't necessarily designed to handle.

What Should You Do If Ice Dams Keep Coming Back?

If you've had recurring ice dams—especially if they returned after having the roof replaced—I would start with a thorough inspection rather than immediately assuming something is wrong with the new shingles.

Look at the entire roofing and attic system.

A contractor should be asking questions such as:

Is there enough insulation?

Where is heat entering the attic?

Is there adequate intake ventilation?

Is there adequate exhaust ventilation?

Are the intake and exhaust properly balanced?

Is excess heat warming the roof deck during the winter?

The visible ice dam is the symptom.

The goal is to identify the conditions creating it.

At Sharp Roofing, when we encounter these types of problems, we want to understand what's happening underneath the roof before recommending the solution. That's especially important in Michigan, where our roofs have to deal with snow, freezing temperatures, thawing, and major temperature swings throughout the year.

A properly installed roof matters.

But so does everything happening underneath it.

Frequently Asked Questions About Ice Dams and New Roofs

Can you still get ice dams with a brand-new roof?

Yes. A new roof does not necessarily eliminate the attic conditions that cause ice dams. If heat continues reaching the roof deck because of inadequate insulation or improper attic ventilation, snow can continue melting and refreezing near the colder roof edge.

Will replacing my shingles fix an ice dam problem?

Not necessarily. New shingles can address an aging or damaged roofing system, but recurring ice dams may require improvements to insulation, intake ventilation, exhaust ventilation, or a combination of those components.

Does attic ventilation help prevent ice dams?

Proper ventilation can be an important part of the solution. Intake ventilation helps bring outside air into the lower portion of the attic while exhaust ventilation allows warmer air to escape higher on the roof. The system needs to be properly sized and balanced rather than simply adding vents at random.

Why does insulation matter for ice dams?

Insulation helps slow heat transfer from the home's living space into the attic. If too much heat reaches the roof deck, it can melt snow sitting above it. That water may then flow toward the colder eaves, refreeze, and gradually create an ice dam.

Look Beyond the Shingles

One of the most important things homeowners can understand about recurring ice dams is that the problem you see on top of the roof may actually begin underneath it.

Replacing an old roof may be necessary, but if the attic continues building up excessive heat, the conditions that caused the ice dam can remain.

That's why insulation, intake, exhaust, and the roofing system should be evaluated together.

When those components are working properly, you're not just addressing ice dams. You're helping create a roofing system that can perform better through Michigan winters, summer heat, and everything in between.

If you're dealing with recurring ice dams or aren't sure whether your attic and roofing system are working together properly, contact Sharp Roofing for a professional roof and attic evaluation.