Why Do Shingles Go Bad? Where Roofs Leak—and What a New Roof May Cost

Most homeowners don’t spend much time thinking about their roof until something gets their attention: a missing shingle, a ceiling stain, or water dripping where it shouldn’t.

Then come the questions:

“Why are my shingles curling?”“Where is that water getting in?”“Can you repair it, or do I need a new roof?”“What’s this going to cost?”

At BMG Exteriors, we believe you deserve clear answers before making a decision about your home.

I started in the roofing trade in 1988. One lesson that has stayed with me: find the cause, explain the problem, and recommend the work the home actually needs.

Here’s what we look for when inspecting an asphalt shingle roof.

Why Do Asphalt Shingles Deteriorate?

1. Age and Weather Exposure

Your roof sits outside through every hot summer, cold winter, and passing storm.

Over time, shingles can develop cracks, curling edges, and worn areas. Aging or cracked shingles may lose protective granules and develop openings that allow water into the roofing system.

Age gives us a starting point, but it doesn’t tell the whole story. We want to see the condition of the roof before recommending replacement.

2. Attic Moisture and Ventilation Problems

What’s happening underneath the roof matters, too.

Moisture in the attic can sometimes be mistaken for a roof leak. Wet insulation, staining, or rust around roofing nails may point to condensation and a need to investigate ventilation and moisture sources.

That’s why an inspection may need to include the attic as well as the shingles.

3. Wind and Physical Damage

Missing, torn, or lifted shingles deserve attention after a storm. Branches and rooftop activity can also leave damage that needs closer inspection.

Our job is to determine the extent of the problem and whether a localized repair makes sense.

4. Installation Problems

The materials are only part of the job. Nail placement, flashing, underlayment, and the details around roof openings all need attention during installation.

When we inspect a roof, we look beyond its appearance. We want to understand how the system was put together and where it may be falling short.

5. Granule Loss and Surface Changes

Worn patches and exposed areas deserve a closer look. But black streaks alone don’t establish that your roof is failing. Those streaks are commonly caused by algae and may be primarily an appearance issue.

We won’t recommend a new roof based on a stain alone. We’ll inspect the roof and explain what the findings mean.

Where Do Shingle Roofs Leak—and How Does Water Get Inside?

A shingle roof includes a lot more than shingles. Places where the roof meets a wall, chimney, pipe, or skylight are common areas to investigate.

Here are the locations we pay close attention to.

Around Chimneys

Flashing forms the connection between the roofing and the chimney. When that connection deteriorates or has gaps, water can enter around the chimney.

Around Plumbing Vent Pipes

The pipes sticking through your roof need flashing that seals the opening around them. Deteriorated flashing can give water a route into the home.

Around Skylights

We inspect the skylight and its surrounding flashing. A stain near a skylight needs investigation before deciding which component requires repair.

Where the Roof Meets a Wall or Dormer

These transitions depend on properly installed flashing to direct water back onto the roof surface. Openings or failing details can allow water into the assembly.

In Roof Valleys

A valley is where two roof slopes meet. These areas handle concentrated runoff, making the condition of the roofing and flashing especially important.

Along the Lower Roof Edges

Eaves deserve attention because they can be vulnerable to wind-driven rain and ice dams. Chimneys, skylights, plumbing vents, walls, valleys, and eaves are all identified in GAF’s guidance as areas to investigate when finding leaks.

Through Damaged Shingles or Backed-Up Drainage Areas

Cracked shingles, damaged flashing, and gutters that redirect water beneath shingles can all contribute to leaks.

The ceiling stain tells us where you noticed the problem. An inspection helps us determine where the water is getting in.

Do You Need a Roof Repair or a Full Replacement?

A leak deserves attention. It also deserves a diagnosis.

If the problem is limited and the surrounding roof remains serviceable, a repair may be a practical option.

If deterioration is widespread, leaks keep returning, or previous repairs aren’t holding up, replacement may be the better investment.

At BMG, we’ll show you photos, explain what we found, and walk through your options.

You should understand why we’re recommending the work before you agree to it.

How Much Does a New Shingle Roof Cost?

Roof replacement pricing depends on more than the size of your house.

We consider:

• Roof area, slope, and complexity.

• Access and property protection requirements.

• Existing roofing layers and removal.

• Decking condition and necessary repairs.

• Shingle selection and roofing system components.

• Chimneys, skylights, walls, and other flashing details.

• Ventilation work included in the project.

The following figures are general planning examples, subject to inspection and a written estimate:

General project description	Illustrative price range
Smaller, straightforward roof	$6,000–$8,000
Mid-size roof with moderate complexity	$8,000–$12,000
Larger, steeper, or more complex roof	$12,000–$18,000+

Some projects fall outside these ranges. Your proposal should explain the work included and how concealed damage or additional repairs will be handled.

A clear price starts with a clear scope.

What Should Your Roof Replacement Estimate Include?

Look for an explanation of:

• Tear-off and disposal of existing roofing.

• The shingles and underlayment being installed.

• Ice and water protection included in the scope.

• Flashing, roof edges, and penetration details.

• Planned ventilation work.

• Property protection and cleanup.

• Applicable workmanship and manufacturer warranties.

Every house is different. We want you to know what we’re doing at yours.

The BMG Way: Customer First…Always.

A roofing project should come with clear expectations and regular updates.

That’s where our commitment to relentless communication comes in. We explain the findings, discuss the schedule, and keep you informed if something changes.

If we uncover damaged wood, you’ll hear from us. If weather affects the plan, you’ll get an update. If a concern comes up, we take ownership and work toward a solution.

That’s the experience we work to deliver—from the first call through the final cleanup.

Call Mike—He’ll Take Care of You

That recommendation means something to me. It means someone trusts us enough to put their own name behind ours.

If you’re dealing with missing shingles, a recurring roof leak, or an aging roof in Pennsylvania, New Jersey, or Delaware, let’s take a closer look.

We’ll inspect the roof, show you what we find, and explain your repair or replacement options in plain English.

Contact BMG Exteriors to schedule your roof inspection and request a straightforward estimate.

Built on Experience. Driven by Integrity.

—Mike and Team BMG