Key Takeaways
- Yes, you can install a metal roof over a shingle roof, but only if the existing roof is in good condition and local building codes allow it. In our service area as a roofing company in Berks County it’s not an issue.
- Why would someone install metal over shingles? Skipping a full tear-off saves considerable time and money, but proper installation with furring strips or underlayment is ideal to prevent issues down the road.
- Not sure what’s ideal for you? Professional roof installation makes for long-term durability and avoids costly mistakes like improper fastener placement, moisture buildup, or structural overload.
Introduction
At Rockland Builders, we’ve installed metal roofs for years, and one of the most common questions we hear is: “Can I install a metal roof directly over my existing shingles?”
The short answer? In many cases, yes – but just because you can doesn’t always mean you should.
Proper installation (either over shingles or not) is key to avoiding issues like moisture buildup, uneven surfaces, and potential code violations. Let’s break it down so you can make the right call for your home.
Why Homeowners Choose to Install Metal Roofing Over Shingles
- It Saves on Labor Costs – Tearing off an old roof is expensive and time-consuming. A metal roof-over lets you skip that step and save money.
- It Produces Less Waste – Keeps your old shingles out of the landfill and reduces environmental impact.
- It Provides A Little Extra Insulation – Your existing asphalt shingles act as a built-in layer of insulation, helping to regulate indoor temperatures. It’s small, but it is a thermal barrier.
- Metal Roofing Provides Energy Efficiency – Unlike a shingle roof, which absorbs some heat, a standing seam metal roofor ag panel roof reflects sunlight, which means lower cooling bills in the summer.
- It Lasts for Decades – While an asphalt shingle roof may start wearing out after 20 years, standing seam metal roofing holds strong for 40–70 years with minimal-to-no maintenance.
What to Consider Before Installing Metal Roofing Over Shingles
First off, your roofing contractor is the best person to make this call, but here are a few considerations.
1. Check Local Building Codes
- Some areas require a complete tear-off before installing a new metal roof.
- Structural integrity is key. Adding multiple layers of roofing materials could push the weight limit of your home’s framing and roof trusses.
2. Inspect the Condition of the Existing Shingle Roof
- If your shingle roof is sagging, cracked, or uneven, installing metal on top could lead to bigger problems.
- The roof deck underneath must (absolutely must!) be solid and free of rot to support the new roof.
3. Use a Furring Strip System (Strapping) or Underlayment
- Furring strips (purlins) help create a level surface for the metal roof to go on, improve ventilation, and prevent the old shingle pattern from showing through the metal panels.
- Underlayment adds an extra moisture barrier to protect against leaks and condensation issues.
4. Structural Load Considerations
- Metal roofing is lightweight, but stacking it on top of existing asphalt shingles could stress your home’s structure. If your roof already has multiple layers, a full tear-off might be necessary.
5. Choosing the Right Fasteners and Attachment Method
- Longer screws may be necessary to secure the metal roofing panels into the roof deck.
- Spacing fasteners correctly prevents warping, shifting, or water leaks over time.
Pros & Cons of Installing a Metal Roof Over Shingles
| Pros | Cons |
|---|---|
| No messy, expensive tear-off required | Some local building codes require shingles to be removed |
| Faster roof installation and lower labor costs | Existing shingles must be in good condition |
| Metal reflects heat, improving energy efficiency | Uneven shingles could cause an imperfect surface |
| Adds extra insulation and soundproofing | Poor ventilation could lead to moisture buildup |
Final Verdict: Should You Go for a Metal Roof Over Shingles?
Installing a metal roof over an existing shingle roof can be a smart, money-saving choice, but only if it’s done right. The condition of your existing roof, local building codes, and proper roof installation techniques all play a role in whether this is a solid investment or a shortcut that will cause problems later.
At Rockland Builders, we specialize in professional metal roof installations in Reading and Allentown, PA. Whether you’re upgrading from an asphalt shingle roof, need a full roof replacement, or are putting a new roof on a new home, our roofing team is focused on a high-quality installation that lasts.
If you’re considering a new metal roof in Reading, reach out today for a free consultation and let’s discuss the best roofing solution for your home.
