3 minutes
If you own a home in Norwell, Hull, or Cohasset and your roof is showing signs of wear, you’ve probably heard two terms thrown around: roof replacement and roof overlay (sometimes called “re-roofing”). On the surface, they sound similar — both involve adding new shingles — but the difference can mean thousands of dollars and years of lifespan.
Let’s break down what each method involves, the pros and cons for coastal Massachusetts homes, and how to decide which is right for you.
What Is a Roof Replacement?
A full roof replacement means tearing off all the old roofing materials down to the deck and installing brand-new underlayment, flashing, and shingles.
Steps Include:
Removing old shingles, nails, and underlayment.
Inspecting the roof decking for rot, mold, or structural damage.
Installing new underlayment (often with ice & water shield in Massachusetts).
Adding new shingles and flashing.
What Is a Roof Overlay?
An overlay involves installing a new layer of shingles directly on top of the existing roof. It’s faster and less labor-intensive because there’s no tear-off.
Steps Include:
Inspecting the existing roof for stability.
Laying new shingles over the old layer.
Massachusetts Code Tip: You can’t have more than two layers of roofing — if you already have two, you’ll need a full tear-off.
Pros and Cons of a Roof Replacement
Pros:
Longest possible lifespan for the new roof.
Opportunity to inspect and repair the decking.
Better long-term resale value for homes in Cohasset’s competitive market.
No hidden problems left under the old shingles.
Cons:
Higher upfront cost.
More labor and time — can take several days.
Pros and Cons of a Roof Overlay
Pros:
Lower upfront cost.
Faster — often completed in 1–2 days in towns like Norwell.
Less mess because there’s no tear-off.
Cons:
Adds extra weight to the roof, which can be risky for older homes in Hull.
Shorter lifespan than a full replacement.
Cannot address hidden damage under the old shingles.
May not be eligible for full manufacturer warranties.
How Coastal Weather Changes the Equation
Hull: Strong ocean winds can lift both new and old layers if the base isn’t secure.
Cohasset: Salt air can corrode nails and flashing — problems that overlays can hide.
Norwell: Snow and ice dams can form between old and new layers if ventilation isn’t improved during installation.
Cost Comparison in the South Shore Area
Full Replacement: $12,000–$25,000 depending on size, materials, and complexity.
Overlay: $8,000–$15,000, but with a shorter expected lifespan (often 10–15 years vs. 20–30).
When to Choose Replacement
If your roof decking is over 20 years old.
If you have existing leaks or soft spots.
If you want maximum resale value (especially in high-value areas like Cohasset).
If you have more than one layer of shingles already.
When an Overlay Might Work
If your existing roof is in good structural condition.
If you need a short-term budget-friendly solution.
If you plan to sell soon and want to improve curb appeal quickly.
The Warranty Factor
Many shingle manufacturers only honor full warranties on roofs installed after a complete tear-off. For South Shore homeowners, that can mean the difference between decades of coverage and just a few years.
Final Recommendation for Norwell, Hull, and Cohasset Homeowners
If your goal is long-term protection against coastal winds, salt exposure, and Massachusetts winters, a full roof replacement is almost always worth the investment. Overlays can be tempting for their lower cost and quick turnaround, but they’re better suited for short-term situations.
Amy Johnson
Amy runs the show at Associate.