Can You Install a Metal Roof Over Shingles?
If it is time for professional roof replacement, you may assume that because your roof has asphalt shingles, that you need to remove them and replace them with new asphalt shingles. However, this is not the case, as you can redesign your roof with any type of material. You can install the new roofing system over the shingles instead of removing them. Installing one roof over another roof is known as a roof overlay.
Metal roofing is one of the most popular options for replacing shingles. Metal roofing offers as many design features as shingles, but with greater durability, storm protection and energy-efficiency. In our latest article, we discuss the pros and cons of installing a metal roof over shingles and why metal roofs are a smart option.
What to Consider When Installing a Metal Roof Over Shingles
If you are thinking about a roof overlay, there are several key issues you should consider:
The Metal Roof Design
Although just any metal roof can fit over shingles, some metal roof designs or panels perform better without the shingles. You need to consider how much space you need between the metal panels and the asphalt shingles and whether the shingles will fit. Overall, the design needs to be compatible with the existing roofing.
Manufacturer Warranty and Specifications
Some manufacturer warranties will not cover the metal roof if you install it over asphalt shingles. Some manufacturers may offer a warranty but exclude coverage for any problems that are related to the asphalt shingles. Make sure you understand the conditions of the warranty before you purchase the metal roof.
Section 1511.3.1 of the International Building Code (IBC) provides the following guidelines regarding installing a metal roof over asphalt shingles:
“The installation of a new roof covering over an existing roof covering shall be permitted where any of the following conditions occur: Complete and separate roofing systems, such as standing-seam metal roof panel systems, that are designed to transmit the roof loads directly to the building’s structural system and that do not rely on existing roofs and roof coverings for support, shall not require the removal of existing roof coverings.”
In simple terms, if the asphalt shingles are not used to support the metal roof, then you can install a metal roof over the asphalt shingles. The metal roof must rely on the building’s framework for full support.
The Weight of the Roofing System
Most buildings are designed to support the heaviest roofing systems. However, the combined weight of asphalt shingles and metal roofing may require additional support in the roofing structure. This is especially true if the structure is older and not designed for modern roofing materials. Before undertaking a residential or commercial metal roof installation, make sure the building can support both roofs long-term.
Pros and Cons of Roof Overlays
There are several advantages and disadvantages of installing a roof overlay:
- Lower cost due to less time and labor
- Shorter job timeline, earlier due date
- Less clean up after job completion
- Greater energy efficiency due to multiple roof layers
- Multi-layer protection and insulation
- Prevents shingles from being thrown in landfills
- Risk of unnoticed pre-existing damage underneath the shingles
- Shorter potential lifespan of the entire roofing system
- Additional labor when performing roof repairs or maintenance
- Additional weight on the decking and supporting framework
- Potential lower property value
If you tear the old asphalt shingles off, then your roof gets all-new materials. This can revitalize your roofing system and give it another 50 to 100 years of life. Removing the old shingles also opens up opportunities for renovating or upgrading your roof. A brand new roof free of old shingles can add up to $10,000 to your building’s resale value.
If you keep the shingles on the roof, you can save hundreds of dollars in labor and removal costs. The roofing contractor can also complete a professional roof replacement much faster. Having multiple layers of roofing can provide more insulation and protection to your home, lowering your heating and cooling costs annually.
Preparing for a Roof Overlay
Before you install a metal roof over shingles, you need to prepare the roofing system for the roof overlay. First, you need to address any potential long-term issues, such as leaks or roof damage. If you don’t take care of these problems early on, fixing them down the road will be more difficult since there are two layers of roofing.
Your roofing contractor should conduct a complete roof inspection. They should identify any issues that compromise the structural integrity of the roof. They may also have to renovate the structure or add framework to support the metal roof. Next, your contractor needs to look for roof damage or problems in previous workmanship. The current roof needs to be in like-new condition before you add the new layer of metal roofing.
Advantages of a Metal Roof Over an Asphalt Shingle Roof
There are several reasons why metal roofs are a better investment than asphalt shingles.
Flexible Finish Options
Metal roofs have come a long way in overcoming the stigma that they only work in a few applications (mostly agricultural or commercial). Today’s metal roofs are available in a variety of colors, textures and sizes. Some metal roof designs mimic the look and feel of other roofing types such as asphalt shingles, tile or cedar shakes. If you can find a design you like in asphalt shingles, you can find a similar design in metal roof panels.
With the exception of tile, metal roofs have the longest durability of any type of roofing material on the market. Asphalt shingles have an impressive lifespan of up to 30 years. However, metal roofs can last up to 50 years. You can increase their lifespan beyond 50 years with routine maintenance and care. Metal panels are more expensive than asphalt shingles, but they are a much better investment due to their longevity.
Greater Protection and Insulation
It is true that metal roofs can get quite hot in the summertime. However, a metal roof can reflect the sun’s rays and resist high temperatures far better than asphalt shingles. They are also more soundproof and provide more protection against high winds and torrential rains. Metal panels are more likely to hold up in hurricane weather than asphalt shingles.
Schedule a Free Roof Inspection
Quality Roofing Solutions offers premier roofing services for homeowners in Pensacola, Milton, Pace, Gulf Breeze and the surrounding Gulf Coast area. To schedule a free roof inspection, call (850) 378-3757 or fill out the quick form on our contact page.