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Should I Install My Metal Roof Over an Existing Roof?

May 31, 2023

Should I Install My Metal Roof Over an Existing Roof?

Should I Install My Metal Roof Over an Existing Roof?

Metal roofing has become extremely popular among homeowners for its longevity, durability, and energy efficiency as a roofing solution. If your home is anything but a metal roof, like a shingle roof, you may be wondering if there’s still a chance that you can get a metal roof installed over it? We’re here to tell you that you can absolutely have a metal roof installed over an existing shingle roof. However with all home improvement projects, installing a metal roofing over an existing roof comes with its pros and cons.

Determining whether to remove or roof over your current roof:

1) Number of layers: This is the easiest way to determine if you have to remove your roof or not. If you have more than 1 layer (i.e. 2 layers) you cannot install a 3rd layer of roofing material. Due to local building codes, 2 is the maximum amount of pitched roofing layers.

2) Wavy or buckling roof:
If your roof is wavy or buckling, chances are you have plywood underneath the roof that is warped or rotted. In this case you need to remove your roof to repair or replace any damaged sheets. Additionally, no one wants a wavy roof, so in this case you should definitely remove your old roof.

3) Inspect your Plywood from the Attic:
Even if your roof looks smooth, you should still visually inspect the underside of the roof to make sure no plywood is moldy or rotten. When tearing off your old roof, we are able to effectively replace any rotten or damaged plywood.

Benefits of installing a Metal Roof over my Asphalt Roof:

1) Going Green: Every year 1.3 billion pounds of petroleum-based asphalt goes into the landfills which you can help prevent by installing a lifetime metal roof directly over your existing asphalt roof.

2) Saving Money: It’s always good to “go green” especially when it helps you save money. By installing a metal roof over an existing roof, you can save thousands of dollars on removal and disposal costs, making your dream roof that much more affordable.

3) Energy Efficiency: Metal roofing is already Energy Star Rated for its ability to reflect heat but having the extra layer of asphalt will add to your attic’s insulating value.

4) Sound Dampening: The extra layer of asphalt will also make your roof quieter during heavy rain storms.

Concerns of Installing a Metal Roof over my Asphalt Roof:

1) Aesthetics: Depending on what shingle you currently have and what metal roof you plan on installing will help determine if you should remove your roof or not. Typically, Metal Shake or Slate looks better than Standing Seam when installed over your old roof. This is because the Metal Shake and Slate panels are raised and can cover any imperfections in your roof. For all standing seam installs, we recommend a complete removal unless you have a flat 3-tab shingle with a completely flat roof.

2) Replacing Old Plywood: If you are doing a roof over, it is difficult to replace plywood that is damaged as mentioned in the first section. If you do not have access to your attic or cannot visually inspect your plywood then it may be a safer choice to remove your old roof versus installing over top.

Before you purchase your next roof, contact Global Home Improvement and our metal roofing experts to schedule a free metal roofing consultation. Our courteous and professional staff can help you determine which metal roofing solution is right for your home.

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