To install metal roofing over shingles, inspect the roof and deck, confirm the metal system is approved for overlay, add an approved underlayment, fasten the panels to manufacturer specifications, and finish the flashing, trim, and final inspection, all without a full tear-off.
In Florida, this metal roofing method only works when the existing asphalt shingles are in good condition, the roof deck is structurally sound, and the installation meets Florida Building Code, wind-resistance, and permitting requirements. When it does, homeowners skip the tear-off, which means lower labor costs, less landfill waste, and a faster install. Professional crews often finish in 1 to 3 days.
This guide from Embick Roofing, serving Palm Beach and Martin Counties since 1978, covers the step-by-step process, the tools and materials you need, Florida requirements, when a full tear-off is the safer choice, and how to decide between DIY and hiring a professional.
Can You Install Metal Roofing Over Shingles in Florida
Yes, metal roofing can sometimes be installed over existing asphalt shingles in Florida, but it is not appropriate for every roof. The existing shingles must be suitable for an overlay, the roof deck must be structurally sound, and the selected metal roofing system must allow installation over shingles.
Before installation, a roofing professional should evaluate the existing roof condition, number of shingle layers, roof slope, decking, ventilation, flashing, and signs of moisture damage. The project must also follow the metal roofing manufacturer’s approved installation method, applicable Florida Building Code requirements, and local permitting rules.
If the existing roof has significant deterioration, structural damage, excessive shingle layers, or other conditions that prevent an approved overlay, a complete tear-off may be necessary.
Why Homeowners Choose Metal Over Shingles
It’s not only convenient when installing metal over shingles. There are real benefits.
Key advantages include:
- Reduced labor expenses (no tear-off)
- Less landfill waste
- Faster installation
- Additional layer of insulation
- ·Longer roof lifespan
Metal roofs can endure 40-70 years, but regular shingles often require roof repair after 20-25 years.
When Metal Over Shingles Should NOT Be Installed
This method isn’t suitable for every roof.
Avoid it if:
- The roof deck has rotting or sagging
- The shingles are curled, fractured, or uneven
- There are already two layers of shingles
- You have serious ventilation issues
In these situations, a complete tear-off is more practical and safe.
How Metal Roofing Is Installed Over Shingles
Installing metal roofing over existing shingles is a multi-step process that starts with evaluating the existing roof and confirming that an overlay installation is appropriate. The roofing contractor must consider the condition of the shingles and roof deck, roof slope, existing roofing layers, selected metal roofing system, manufacturer requirements, and applicable building and permitting requirements. When the existing roof is suitable, the installation can proceed without a complete tear-off.
Step 1: Inspect and Prepare the Existing Roof
The first step is to inspect the roof of the existing shingles, roof deck, flashing, and other roofing components for damage or deterioration. The contractor looks for problems such as moisture intrusion, damaged decking, significant shingle deterioration, uneven areas, or conditions that could prevent proper installation. Any issues that could affect the new roofing system should be addressed before the metal panels are installed.
Step 2: Confirm the Approved Installation Method
Not every metal roofing system can be installed over existing shingles. The contractor should confirm that the selected system allows an overlay installation and determine the appropriate installation method based on the roof’s condition, slope, existing layers, manufacturer specifications, and applicable requirements. This step helps ensure that the new roofing system can be properly supported, attached, and flashed.
Step 3: Prepare the Substrate and Underlayment
Once the existing roof has been evaluated and approved for an overlay, the roofing surface is prepared for the new system. Depending on the selected metal roofing system, this may involve installing an approved underlayment, separation layer, or other components required by the manufacturer and applicable project requirements. The goal is to provide a suitable surface for the new roofing system while addressing areas that could affect its performance.
Step 4: Install the Metal Roofing System
The metal roofing panels or other components are then installed according to the manufacturer’s specifications and the approved installation method. Fasteners, attachment points, panel overlaps, and other installation details should follow the requirements for the specific metal roofing system rather than a universal screw size or spacing pattern.
Step 5: Complete Flashing, Trim, and Ridge Details
Flashing and trim are installed around roof edges, valleys, walls, vents, chimneys, and other roof penetrations as applicable to the roof design. Ridge and eave details are also completed according to the selected roofing system. Proper detailing helps direct water away from vulnerable areas and provides a finished, weather-resistant roofing assembly.
Step 6: Inspect the Completed Roof
After installation, the completed roofing system should be inspected to verify that panels, fasteners, flashing, trim, and other components have been installed correctly. The contractor should also check for visible installation issues and clean the work area. A final inspection may also be required depending on the project and applicable permitting requirements.
Tools And Materials You’ll Need
Get everything together before learning how to install metal roof over shingles.
Basic Tools:
- Chalk line
- Drill or impact driver
- Metal snips or shears
- Safety harness and gloves
- Tape measure
Materials:
- Synthetic barrier or roofing underlayment
- Metal roofing panels
- Closure strips
- Ridge cap and trim pieces
- Screws with rubber washers
- Furring strips or battens (optional)
Florida Requirements For Installing Metal Roofing Over Shingles
Installing metal roofing over shingles in Florida requires more than selecting a durable roofing material. The project should comply with applicable building codes, permitting requirements, wind-resistance provisions, and the metal roofing manufacturer’s installation specifications.
Before installation, verify:
- Whether the existing roof can remain in place
- The number and condition of existing shingle layers
- The condition of the roof decking
- Required underlayment or separation materials
- Fastening and wind-resistance requirements
- Flashing and ventilation requirements
- Applicable roofing permits and local requirements
For homes in hurricane-prone areas such as Jupiter, the entire roofing assembly matters. The metal panels, fasteners, substrate, underlayment, flashing, and installation method must work together to provide the required weather and wind resistance.
A licensed roofing contractor can evaluate the existing roof and determine whether installing metal roofing over shingles is appropriate or whether a complete tear-off is necessary.
Common Mistakes To Avoid
Mistakes can happen even to experienced installers.
Watch out for:
1. Inadequate ventilation planning
2. Installing over damaged shingles
3. Skipping underlayment
4. Using the incorrect screw length
5. Ignoring local building codes
Preventing these kinds of mistakes protects your investment.
DIY Vs Hiring A Professional
You can do this on your own, but it’s not always simple.
DIY is good if:
- You have roofing experience
- The roof is simple
- You adhere to safety regulations
If your roof is complicated or steep, you want a warranty, or local codes are stringent, it’s better to hire a professional.
Professional installers like Embick Roofing are fully aware of the safe and proper methods for installing metal roofing over shingles.
How Long Does Installation Take?
For an average home:
- DIY: 3–7 days
- Professional Crew: 1–3 days
Timing can be affected by weather, roof size, and experience level.
Cost Considerations
Compared to a complete tear-off, installing metal over shingles is typically less expensive.
Price-affecting factors include:
- Metal panel type
- Roof size and slope
- Underlayment choice
- Labor (DIY vs contractor)
Metal roofing is more expensive initially, but it frequently pays off over time.
Conclusion
Understanding how to install metal roofing over shingles offers homeowners a cost-effective and time-saving roofing solution. When done properly, this technique produces a new, long-lasting roof without the hassle of pulling off old shingles.
Installing metal over shingles can be a reliable solution that increases strength and value if your roof is in good shape and local codes permit it.
