How to Install Metal Roofing over Shingles? | Considerations and Approaches

Many homeowners are curious about how to install metal roofing over shingles for various reasons. Some of them are the advantages of metal roofs over asphalt shingles, for instance, their durability.

Anyone interested in metal roofing can take advantage of the fact that they do not have to tear off the original shingle roof. Although this is a possible task, it’s not always recommended.

You need to be mindful of when you should and shouldn’t do it and the potential issues you’ll face. This blog tells you some considerations, essential requirements, and approaches to installing metal roofing over shingles.

Advantages of Metal Roofs Compared to Shingle Roofs

Even though both metal roofing systems and asphalt shingle roofing are excellent options, metal roofing has son noticeable advantages:

Better Durability and Resistance

Metal roofing tends to be extremely durable in the proper conditions. Additionally, it is tested to resist extreme weather conditions, such as heavy storms and winds. It is less vulnerable to damage due to its resistance.

Long-Lasting Protection

Shingle roofing has a life expectancy of up to 25 years in ideal conditions. In contrast, metal roofing has a durability of 50 years or even more. Which means it is twice as durable as shingles roofing.

Sustainable and Eco-Friendly Solution

Metal roofing is recyclable, in fact, most of the metal roofing panels have already gone through a recycling process. That doesn’t happen with shingle roofing, as most of it simply goes to the trash after removing it. Additionally, it is a lot more energy-efficient compared to shingle roofing.

Low-Cost Maintenance

Metal roofing tends to cost more than shingle roofing, likewise, the installation cost is higher. Even so, metal roofs are less likely to suffer severe damage over time, which means that their maintenance costs are generally much lower than those of asphalt shingles.

Lightweight

Metal roofs are generally lightweight. An asphalt shingle roof is 50% heavier than metal roofing. When planning to install metal roofing over existing shingles, this is an important factor since you will know you won’t be adding too much weight, and therefore, stress to your home’s structure.

When Should You Overlay a Shingle Roof with Metal Roofing?

Metal roofing has become one of the preferred types of roofing in the United States due to its benefits. However, is it advisable to install them over asphalt shingles?

Vital Requirements to Install Metal Roofing over Shingles

1. Weight: Although weight is not a big issue for metal roofing, you must know how much weight you put on your original roof and house.
2. Building codes: This factor is highly related to the one above. Some basic requirements affirm that you can’t put more than a specific amount of roof layers in a property.
3. Shingle roof condition: Make sure that your original shingle roof is in good condition. Installing a metal roof over a damaged shingle roof can worsen the problem.

The first step must always be performing a roof inspection to determine the condition of your original roof. If you found minor damages, you could repair it. If there are signs of structural damage, you must remove the shingles.

A roofing contractor should be able to determine your roof condition. Call us to get roofing repair services in Kennewick, WA.

Pros and Cons of Installing Metal Roofing over Existing Shingles

The truth is that placing metal roofing over existing shingles will save you the labor cost of the complete tear-off. Additionally, leaving your original roof in place will generate less pollution. Furthermore, once it accomplishes its life expectancy, you’ll be able to recycle it.

Moreover, the existing shingle roof will act as a sound insulation barrier that will minimize the noises in metal roofing.

However, one of the main drawbacks of placing metal roofing on existing shingles is that you are adding more weight to your house. Additionally, even with a roofing inspection, you can still miss some flaws in your shingle roofing, which may cause problems in the future.

Metal Roof Installation Over Shingle: Different Approaches

There are some established methods and approaches to installing metal roofing over existing shingles; these are the following:

Purlins Attached to The Existing Roof Deck

Use purlins attached to the existing roof deck or directly on the shingle roof, and then attach the metal roof panels. This approach creates an air gap between the existing shingle roof and the new metal roof.

The main benefit of this method is that it helps to avoid transferring heat into the shingle roof and the house. Additionally, you’ll have a flatter base, which will result in a consistent metal roof.

Underlayment Between Shingles and Metal Roofing

The second approach will be adding an underlayment directly on the shingle roofing. This layer act as a separation barrier between the shingles and the metal panels.

Additionally, this barrier protects the back of the metal panel from suffering damage by shingle granules and moisture. A waterproof synthetic underlayment will be a good option for this.

Unfortunately, with this option, the panels will take the shape of what is under them, in this case, the asphalt shingles, which will result in an uneven roof.

You could also use an insulation material such as fanfold or flute fill to stop heat transfer.

Naturally, a metal roof tends to expand and contract. Consequently, these installation methods also protect the metal roof panels from suffering damage due to friction between both roof materials.

Receive Professional Assistance to Install Metal Roofing over Shingles

Whether you choose to hire a professional, it’s always good to know how to install metal roofing over shingles. By knowing it, you’ll rest assured that you’re making the right decision, without compromising the structure of your residence.

Additionally, all this knowledge can also help you on finding the right company to take on the project properly.

If you consider this option for your property, you can contact our roofing professionals at All City Roofing. We have an extensive understanding of roofing installation and repair services. If you have any other doubt, don’t hesitate to reach out to us!

Call us  to obtain a free estimate for your next roof installation project!