Metal roofing is a popular choice for homeowners due to its durability, energy efficiency, and low maintenance requirements. If you are considering installing a metal roof, you may be wondering if you can install it over your existing shingles. The answer is yes, you can, but there are a few things you need to do to ensure that the installation is successful.
This blog post will provide you with a comprehensive guide on how to put metal roofing over shingles. We will cover everything from assessing the condition of your existing roof to installing the metal roofing panels and the building codes and requirements to consider. We will also provide you with some expert tips to help you avoid common pitfalls.
Advantages Of Installing Metal Roofing Over Shingles
- Durability And Longevity: Metal roofs are known for their exceptional durability. Unlike asphalt shingles, which can deteriorate over time, metal roofs are designed to last for decades. Some metal roofs can even withstand prolonged gusts of up to 140 miles per hour.
- Energy Efficiency: Metal roofs reflect the sun’s rays, which can help in reducing cooling costs during the summer months. This makes them more energy-efficient than traditional asphalt shingles.
- Low Maintenance: Metal roofs require minimal maintenance compared to asphalt shingle roofs. Regular inspections can help in identifying signs of damage, such as dents or rust, ensuring the roof’s longevity.
- Increased Home Resale Value: Due to their durability, energy efficiency, and low maintenance requirements, homes with metal roofs often have a higher resale value.
- Environmental Benefits: Installing a metal roof over shingles means that the old shingles don’t end up in a landfill. This is an eco-friendly approach, reducing waste and promoting sustainability.
Building Codes And Requirements
Building codes and requirements are essential guidelines set by local, state, or national authorities to ensure the safety, durability, and efficiency of structures. When it comes to metal roofing, adhering to these codes is crucial to ensure the longevity of the roof and the safety of the building’s occupants. These codes address various aspects, from the type of materials used to the method of installation.
Local Building Regulations
- Purpose: Local building regulations are designed to address the specific needs and challenges of a particular region. For instance, areas prone to hurricanes or heavy snowfall might have stricter codes regarding the anchoring and weight-bearing capacity of roofs.
- Material Specifications: Local codes often specify the type of metal that can be used for roofing. For example, in coastal areas, materials resistant to saltwater corrosion, like aluminum or specific types of treated steel, might be preferred.
- Installation Guidelines: How the metal roof is installed can be dictated by local regulations. This includes aspects like fastening methods, underlayment requirements, and seam specifications.
- Inspection And Compliance: After the installation, an inspection might be required to ensure that the new roof adheres to local codes. Non-compliance can lead to fines, the need for rework, or even legal consequences.
- Environmental Considerations: In some regions, environmental considerations play a role in building codes. For instance, reflective roofing materials might be encouraged in hot climates to reduce the urban heat island effect.
- Historical Or Aesthetic Guidelines: In areas with historical or aesthetic guidelines, there might be restrictions or specifications about the appearance of metal roofs to ensure they fit in with the local architecture.
- Permit Requirements: Before starting the installation, homeowners or contractors might need to obtain a permit. This often involves submitting detailed plans and ensuring that the proposed work aligns with local regulations.
Factors To Consider When Choosing A Metal Roof Over Shingles
- Reflectivity: Consider the roof’s reflectivity. A highly reflective roof can significantly reduce cooling costs, especially in warmer climates.
- Emissivity Quality: Emissivity refers to the roof’s ability to release absorbed heat. A roof with high emissivity can help in maintaining a comfortable indoor temperature.
- Type Of Metal Roofing: There are various types of metal roofing options available, including standing seam, metal shingles, and corrugated panels. Each has its own set of advantages and aesthetic appeal.
- Impact Resistance: Depending on the region, it might be essential to choose a metal roof that can withstand hail, debris, and other impact-related damages.
- Roofing Finishes: Metal roofs come in various finishes, from matte to glossy. The finish can influence the roof’s appearance, durability, and maintenance requirements.
Preparing The Existing Roof For Installation
Before installing a metal roof over existing shingles, it’s crucial to prepare the current roof to ensure the longevity and performance of the new roofing system. Proper preparation can prevent potential issues down the line and ensure a smooth installation process.
Inspecting The Current Roof
- Overall Condition: Begin by assessing the overall condition of the existing roof. Look for signs of wear and tear, such as missing or curled shingles, moss or algae growth, and any visible damage.
- Check For Leaks: Inspect the attic and interior ceilings for signs of water damage or leaks. Wet insulation, stained ceilings, or mold growth are indicators of potential roof leaks.
- Surface Scratches: Metal roofs can get scratched by falling branches or during the installation process. It’s essential to identify these early on to address them appropriately.
Doing A Complete Tear-Off Or Extra Layers Of Shingles
- Local Regulations: Some jurisdictions require a complete tear-off of the existing roof before installing a new one. This is especially true if there are already multiple layers of shingles on the roof.
- Advantages Of A Tear-Off: Removing the old shingles can provide a clean slate for the new metal roof, ensuring better adherence and reducing the risk of trapping moisture between the layers.
- Consider The Weight: Adding a metal roof over multiple layers of shingles can add significant weight to the roof structure. Ensure that the building can handle this additional weight.
Making Necessary Repairs Before Installation
- Addressing Decking Issues: Before installing the metal roof, inspect the roof decking for any signs of damage or rot. Any damaged sections should be replaced to provide a solid foundation for the new roof.
- Fixing Leaks: If any leaks were identified during the inspection, they should be addressed before the new roof is installed. This might involve replacing damaged underlayment or patching holes.
- Sealant And Flashing: Ensure that all roof penetrations, such as vents, chimneys, and skylights, are properly sealed and flashed to prevent water intrusion.
- Gutter System: Check the gutters and downspouts for any blockages or damage. A well-functioning gutter system is essential to direct water away from the roof and prevent potential issues.
Choosing The Right Materials And Accessories For The Job
When it comes to installing a metal roof over shingles, selecting the right materials and accessories is crucial. The quality and type of materials you choose can significantly impact the longevity, performance, and appearance of your new metal roof.
Types Of Metal Panels Available
- Aluminum: Lightweight and resistant to corrosion, aluminum panels are available in various styles, including standing seam, corrugated panels, and shingles. They are especially suitable for coastal areas due to their resistance to saltwater corrosion.
- Steel: One of the most common metal roofing materials, steel is durable and can be coated with various finishes to enhance its resistance to rust and UV rays.
- Copper: Known for its beautiful patina over time, copper is a premium roofing material that offers durability and a unique appearance.
- Zinc: A sustainable choice, zinc roofs are recyclable and have a lifespan that can exceed 60 years. They also have self-healing properties, meaning scratches can repair themselves over time.
- Tin: While not as common today, tin roofs are known for their longevity and are often coated for added protection.
Selecting The Right Fasteners For Installation
- Material Compatibility: It’s essential to choose fasteners made of a material compatible with your metal roofing to prevent galvanic corrosion. For instance, stainless steel screws are often recommended for aluminum roofing.
- Self-Drilling Fasteners: These fasteners can drill their own holes, reducing installation time and ensuring a tight fit.
- Corrosion Resistance: Opt for fasteners coated with a rust-resistant material or made from stainless steel to ensure longevity.
- Length: The fastener’s length should be adequate to secure the metal panel to the roof deck securely.
Estimating Square Footage Needed
- Measure Each Roof Section: Start by measuring the length and width of each section of your roof. Multiply these dimensions to determine the square footage of each section.
- Account For Overlaps: When installing metal panels, there will be overlaps between panels. Ensure you account for this when estimating the total material needed.
- Factor In Waste: It’s always a good idea to order a bit extra to account for mistakes, cuts, and future repairs. Typically, adding 10% to your total square footage is a safe bet.
- Roof Features: Don’t forget to account for features like chimneys, vents, and skylights. These will require additional materials and may affect the total square footage.
Installing The New Metal Roof Over Shingles
Installing a metal roof over existing shingles is a practical approach that offers numerous benefits, including cost savings, enhanced durability, and reduced waste. However, to ensure the success of the installation, certain steps and precautions must be taken.
Preparing To Install The New Metal Panels
- Inspect The Existing Roof: Before proceeding with the installation, it’s crucial to inspect the current shingles. Ensure there’s no significant damage, rot, or sagging areas. If the existing roof is in poor condition, it might not provide a solid foundation for the metal panels.
- Clear Debris: Remove any debris from the roof, such as leaves, branches, or loose shingles. A clean surface ensures better adherence of the new panels.
- Install Synthetic Underlayment: While it’s possible to install metal roofing directly over shingles, adding a layer of synthetic underlayment can provide an extra barrier against moisture and improve the roof’s overall performance.
- Consider Insulation: Adding insulation beneath the metal panels can enhance the roof’s energy efficiency. This step can be especially beneficial in regions with extreme temperatures.
- Furring Strips Or Spacers: Before laying the metal panels, consider installing wood furring strips or spacers. These create a gap between the shingles and the metal roof, allowing for ventilation and reducing the risk of condensation. They also provide a flat surface for the metal panels, ensuring a smoother installation.
- Plan The Panel Layout: Measure the roof accurately to determine the number of metal panels required. Plan the layout to minimize cuts and ensure that panels are aligned correctly. Remember to account for overlaps between panels.
- Gather Necessary Tools: Ensure you have all the necessary tools for the installation. This might include metal shears, a drill, roofing screws, a hammer, and safety gear like gloves and protective eyewear.
- Safety Precautions: Working on a roof can be hazardous. Always use safety equipment like harnesses and ensure the ladder is stable. It’s advisable to have a helper or work with a team, especially when handling large metal panels.
Putting Metal Roofing Over Shingles
While installing metal roofing over shingles has its advantages, it’s essential to consider local building codes and the specific requirements of the project. By weighing the benefits against the potential challenges and being informed about the factors to consider, homeowners can make an educated decision that best suits their needs. Preparing the existing roof for a metal roof installation is a crucial step that shouldn’t be overlooked. Proper preparation ensures that the new roof performs optimally and lasts for many years to come. Whether you’re doing a complete tear-off or installing over existing shingles, always prioritize safety and consider hiring professionals for the best results.
Ready for your roofing project? Find the best roofing contractors near you by visiting Roof Nation and exploring our resources to learn more.
