Common Roof Leak Sources in Older Illinois Homes

• Heavy spring rainstorms

• Wind-driven downpours

• Humid summers

• Snow accumulation

• Ice dams

• Freeze–thaw cycles

• Hail events

Over time, these conditions cause roofing materials to expand, contract, crack, and deteriorate.

Older homes may also have:

• Original flashing systems

• Multiple roofing layers

• Outdated ventilation

• Aging decking beneath shingles

These factors increase the likelihood of water intrusion.

1. Failing Flashing Around Chimneys

Chimneys are one of the most common leak sources in older homes.

Flashing — the metal installed where the roof meets the chimney — is designed to create a watertight seal. Over time, flashing can:

• Rust

• Separate from masonry

• Crack at joints

• Lose sealant adhesion

In older Illinois homes, step flashing and counter flashing may not meet modern installation standards.

During heavy rain or snowmelt, water can slip behind compromised flashing and enter the attic or wall cavity.

2. Roof-to-Wall Transitions

Where a roof meets a vertical wall (such as dormers or second-story walls), step flashing is critical.

Older homes often lack proper:

• Kick-out flashing

• Integrated house wrap transitions

• Drip edge installation

Without these components, water running down siding can move behind shingles and penetrate the roof deck.

Wind-driven Midwest rain makes this problem worse.

3. Aging or Curling Shingles

As asphalt shingles age, they lose flexibility. In Illinois’ climate, repeated freeze–thaw cycles accelerate deterioration.

Common issues include:

• Curling edges

• Cracking

• Granule loss

• Exposed nail heads

While leaks rarely start in the center of intact shingles, damaged or lifted shingles allow wind-driven rain to reach underlayment and decking.

If your shingles are 20+ years old, they may be nearing the end of their effective lifespan.

4. Ice Dam Damage

Ice dams are a major issue in Illinois winters.

They form when:

1. Heat escapes through the attic.

2. Snow melts on the roof.

3. Water refreezes at the colder eaves.

The resulting ice barrier prevents proper drainage, forcing water back under shingles.

Older homes often lack sufficient attic insulation and ventilation, increasing ice dam risk.

Leaks caused by ice dams may appear far from the roof edge, making them harder to trace.

5. Vent Pipe and Roof Penetration Failures

Every penetration in your roof is a potential leak point.

Common penetrations include:

• Plumbing vent pipes

• Furnace vents

• Bathroom exhaust vents

• Skylights

The rubber boots or flashing collars around vent pipes degrade over time, especially under UV exposure and extreme temperature swings.

Once cracked, water can follow the pipe directly into your attic.

6. Skylight Leaks

Skylights installed decades ago may lack modern flashing systems and energy-efficient seals.

Common issues include:

• Deteriorated flashing

• Seal failure between glass panes

• Improper curb installation

Older skylights are also less energy efficient, which can increase condensation and moisture buildup inside the home.

7. Improperly Installed or Missing Drip Edge

Many older Illinois homes were built before drip edge flashing became standard practice.

Drip edge directs water into gutters and prevents it from running behind fascia boards.

Without it, water can:

• Rot fascia

• Damage soffits

• Seep beneath roofing materials

Over time, this hidden damage weakens structural components.

8. Multiple Roofing Layers

Some older homes have two or even three layers of shingles.

While building codes sometimes allow a second layer, multiple layers can:

• Trap moisture

• Add excess weight

• Prevent proper inspection of decking

• Hide soft spots

Leaks can develop between layers and remain undetected for extended periods.

Warning Signs of a Roof Leak in Older Homes

Roof leaks aren’t always obvious at first. Watch for:

• Water stains on ceilings

• Peeling paint

• Bubbling drywall

• Musty attic odors

• Mold growth

• Damp insulation

• Increased energy bills

Wet insulation loses R-value, making your home less energy efficient — especially noticeable during Illinois’ hot summers and cold winters.

Long-Term Consequences of Ignoring Roof Leaks

Small leaks rarely stay small.

Over time, untreated roof leaks can lead to:

• Rotting roof decking

• Structural framing damage

• Mold growth

• Insulation deterioration

• Interior drywall replacement

• Electrical hazards

In severe cases, full roof replacement and structural repairs may be necessary.

Early detection saves significant cost.

How Roofing, Gutters, and Siding Work Together

Your roofing system is connected to your entire exterior envelope.

Gutters

Overflowing or clogged gutters can push water beneath shingles at the roof edge.

Siding

Improper siding installation at roof-to-wall intersections can channel water into roofing materials.

Windows

Poor window flashing can allow water into wall cavities, which may appear as a roof leak.

A system-wide evaluation is often necessary to determine the true source.

When Should Older Illinois Homes Consider Roof Replacement?

If your roof is:

• 20–25+ years old

• Experiencing repeated leak repairs

• Showing widespread shingle deterioration

• Lacking modern flashing protection

It may be time for a professional assessment.

Modern roofing systems offer:

• Improved underlayment protection

• Better ventilation integration

• Ice and water shield membranes

• Enhanced wind resistance

• Improved energy performance

Upgrading provides both protection and efficiency.

Frequently Asked Questions

1. Why do roof leaks in older homes seem hard to find?

Water travels along rafters and decking before dripping. The visible interior stain may not align directly with the exterior leak source.

2. Can I repair flashing without replacing the entire roof?

In some cases, yes. If shingles are still in good condition, localized flashing repairs may resolve the issue.

3. Are ice dams more common in older homes?

Yes. Older homes often lack proper attic insulation and ventilation, increasing the risk of ice dam formation.

4. How often should older roofs be inspected in Illinois?

At least once per year — and after major storms — to catch minor issues before they worsen.

Protecting Your Home’s History and Structure

Older Illinois homes deserve careful, knowledgeable care. While aging roofs naturally become more vulnerable to leaks, proactive maintenance and proper installation techniques can extend performance and prevent structural damage.

At Huskie Exteriors, we understand the unique construction styles and weather challenges facing Midwest homes. Our approach focuses on identifying root causes — not just surface symptoms.

If you’ve noticed water stains, suspect flashing issues, or simply want peace of mind about your aging roof, a professional inspection can provide clarity.

Schedule a consultation with Huskie Exteriors and ensure your home is protected — season after season, storm after storm.