When it comes to replacing or repairing a roof, homeowners are often presented with multiple options, one of which is roofing over an existing shingle roof. While this method might seem like a convenient and cost-effective solution, especially in the sunny state of Florida, it is essential to consider the potential disadvantages that can arise from this approach. In this blog post, we’ll delve into the drawbacks of roofing over a shingle roof in the Florida climate.

  1. Trapped Moisture and Heat: Florida’s tropical climate is characterized by high humidity levels and intense heat, which can create an environment conducive to moisture buildup. When you opt to install a new roof over an existing shingle roof, you might inadvertently trap moisture between the layers. This trapped moisture can lead to the growth of mold, mildew, and rot over time, compromising the structural integrity of your roof and your home. Additionally, the heat absorbed by the underlying shingles can get trapped between layers, causing your roof to become hotter than it would be with a fresh installation. This excess heat can accelerate the deterioration of both the new and existing shingles, reducing their lifespan and overall performance.

   2. Weight Load Issues: Roofing materials, including shingles, underlayment, and additional layers, can be quite heavy. By adding a new layer of roofing over an old one, you’re essentially increasing the weight load on your home’s structure. In Florida, where hurricanes and heavy rain are not uncommon, the extra weight can potentially compromise the integrity of your roof’s support system and even your home’s foundation.

    3. Concealed Issues: Overlaying a new roof on top of an old one can mask underlying problems that should be addressed before installing a new roof. Damaged or rotted sections of the underlying shingles, as well as potential structural issues, might not be apparent until it’s too late. This could result in higher repair costs down the line and even more significant damage to your home.

  4. Voided Warranties: Most roofing manufacturers provide warranties for their products, but these warranties often come with specific installation requirements. Roofing over an existing shingle roof might void the warranty of the new shingles, as it may not comply with the manufacturer’s guidelines for proper installation. This can leave you unprotected in case of premature shingle failure or other issues covered by the warranty.

     5. Reduced Curb Appeal: Overlaying a new layer of shingles over an old one can lead to an uneven surface, which can negatively impact the aesthetic appeal of your home. The increased thickness of the roof can cause inconsistencies in appearance, leading to a less polished and cohesive look. This can be especially noticeable in certain lighting conditions, potentially affecting your home’s resale value and curb appeal. 

While roofing over an existing shingle roof might seem like a cost-effective solution, especially in a climate like Florida’s, it’s crucial to consider the potential downsides. Trapped moisture, excess heat, weight load issues, concealed problems, and voided warranties are all disadvantages that can arise from this approach. To ensure the longevity and structural integrity of your roof, it’s advisable to consult with a professional roofing contractor who can provide expert guidance tailored to your specific situation. Ultimately, investing in a proper roof replacement can save you money and headaches in the long run.