Is it Possible to Install a Metal Roof Over Shingles? The advantages of metal roofing versus asphalt roofing systems are numerous. While asphalt shingles are the traditional option, metal roofing is becoming more and more popular in the residential space, providing a long-lasting, durable alternative to asphalt shingles. The durability comes from the material’s resistance to rotting and termites, as well as being an economical choice because it does not require frequent repairs and replacements.
If you already have a shingle roof and are looking to make the switch to metal roofing, you may be wondering how that process works. Do you need a complete roof replacement? Or can you install a metal roof over shingles?
The answer is you can generally install a metal roof on top of shingles if there are fewer than four layers of shingles on the roof, but the exact standards vary by area. However, that process can lead to a variety of complications and therefore is not recommended. In this guide, you will learn the steps necessary to complete a move from a shingle roof to metal roofing and why a metal roof can be an ideal choice for your home.
Why Not Install a Metal Roof Over Shingles?
While installing a metal roof on top of shingles seems like it makes the job easier, metal roofs are a challenging project. The key to a successful roof over shingles is working with a reliable contractor especially if you don’t have experience in roofing, or skills with metal roof installation specifically. The first step in choosing your metal roofing contractor is finding one that is licensed, bonded, and insured. Your next consideration is the contractor’s level of experience. If you’ve never hired someone to install a metal roof before, the last thing you want to do is rush into a project and end up with sub-par workmanship or shoddy materials.
When roofing professionals install a metal roof over shingles, they typically follow this process:
First, the roofer creates a slat board base to support the metal roof on top of the shingles. This is created by laying lengthwise furring boards every two feet along the roof, and then attaching them to the roof with 3-inch wood screws from the bottom of your roof up.
Next, they install metal edging around the perimeter of your roof as well as metal sheets to the framing. Metal sheets need to be installed one at a time with screws spaced two feet apart. Each following sheet overlaps the sheet before it. Once the roof is covered in metals sheets and attached with screws, the roofer will install metal trim along the roof’s edge and top ridge. They should then use notching scissors to put a notch in the metal in the middle so it bends over the ridge.
Lastly, the roofer will install closures or a self-adhesive to seal any openings and prevent moisture, debris, and pests from getting under your metal roofing.
If you are considering installing a metal roof on your house, you should be aware of several problems that can arise when doing so. It’s more difficult to inspect, it could create an uneven surface, and it can ultimately shorten its lifespan. Here are the details on some of the most important reasons why the existing shingle roof should be removed prior to the installation of a new metal roof:
1. The only way to inspect the roof decking and ensure there’s a solid foundation for the new roof is by removing the existing shingles and stripping the roof down to the wood. Removing the old shingles gives the installer a clean start to building the new roof and it gives the roofing professional a more accurate view of what’s going on beneath the hood. Inspecting for wood roots is important since this is where connections will be made and where sound insulation can be installed. This will also ensure that there are no hidden nails or other weaknesses that could let the breeze in or out through the wall, and if there are any signs of damage, like wood root, the entire roofing system needs to be rebuilt.
2. A furring board is a thin, flat, horizontal bar used in roof framing to support a sheathing material and provide space for ventilation. When installing the furring boards over shingles, you risk creating an uneven surface for the metal roofing that can make the final product appear wavy or deformed. Aside from aesthetic issues, if you don’t align all of your shingle rows correctly, then water can potentially flow underneath them and cause leakage.
3. A metal roof’s durability is related in part to how it attaches to the underlying roof sheathing. Some roofers will install metal roofing directly to shingles without laying a wooden base to build upon. A metal roofing that is attached directly to the shingles without a wood base will be susceptible to chipping and peeling sooner than a metal shielded by an additional layer of wood.
Making the switch to metal roofing is a big investment, so you shouldn’t cut corners that will ultimately diminish the value of the new roofing system. When installing a metal roof, it really is best to remove the existing shingle roofing first to avoid any undesirable results.
Benefits of Having a Metal Roof
Metal roofing offers the following significant benefits that make it an ideal choice for today’s homes.
When compared to traditional shingles and other roofing materials, metal roofs do a much better job of keeping your home cool during the summer months. Reflective coatings and thermal breaks can reduce cooling costs by up to 20 percent. Metal roofs reflect the heat from the sun away from buildings, which can save a lot of money spent on central cooling
Fire and Wind Resistant
Fire is a serious threat to any home, and metal roofs help reduce the risk posed by it. Unlike traditional asphalt shingles, a metal roof conducts electricity quickly so any electrical charge that strikes the roof travels through the material and dissipates before producing heat which makes it less likely for lightning strikes to start fires. Additionally, since most metal roofs panels interlock or overlap in some way, they are far more wind resistant than other roofing materials.
50+ Year Life Expectancy
Metal roofs are more expensive than other roofing materials are because they are inherently more durable with a life expectancy of 50 years. While other roofing materials like asphalt shingles can diminish in value and quality as they age, are exposed to wind and rain, and undergo snow and ice exposure, metal roofs provide long-lasting benefits as they are more resistant to weather elements.
Metal roofs come in a wide variety of designs, making them highly adaptable. There are different metal roofing materials available for different types of roofs, including products that mimic the appearance of wood, slate, tile, and even shingles. No matter the style of your home or the complexity of your roof, there are metal materials to suit your needs and preferences.
One of the most significant factors in the choice of roofing material is the tendency of the wall to sag and fail under its own weight. Those problems are particularly serious along long walls or in locations where there have previously been leaks or where heavy traffic has caused problems with the foundations. And the older your home gets, the more damage a weighty roof can cause.
Metal roofs are one of the lowest weight roofing options available for residential homes. Lightweight roofing materials like metal roofing help protect your home from structural movements and the damage caused by that, especially in areas susceptible to earthquakes.
Cost to Install a Metal Roof
The process for installing metal roofs is complex which is why it is important to work with a highly skilled roofer with a great deal of experience to manage this type of installation project. When you’re using a more expensive material, the cost to install a metal roof can be on the higher end of the scale. However, the benefits of metal roofs are numerous and far-reaching making your investment worth it. The benefits of metal roofing over other materials have been proven time and again, including its ability to withstand extreme weather conditions. The longevity of metal also gives you peace of mind knowing your home is protected against harmful elements for decades to come.
Ready to Upgrade Your Roofing?
A metal roof is an investment for your family. It’s a long-lasting roof that requires little to no maintenance, and lasts up to 50 years, providing you with real value. And with Roof Crafters’ Class 4 distinction in impact resistance and Class A fire rating, you can rest assured knowing your roof will not only last but will also help protect your family for a lifetime. With Roof Crafters, you’ll get exceptional craftsmanship and attention to detail – our experts will help you choose the right type of roofing for your personal style. Call 225-667-1189 or contact the Roof Crafters team online today to get a quote, schedule a free, in-home consultation, or find answers to any of your roofing questions in Baton Rouge, Hammond, Mandeville, of the Northshore of LA.