An overlay installation, also known as a roof-over or retrofit installation, involves installing a new layer of roofing material over the existing roof. This can be an appealing option as it eliminates the need for a full roof tear-off, which can be time-consuming and costly.
Advantages of Overlaying:
- Cost-effective: Overlaying a metal roof on top of the existing asphalt shingles can be more cost-effective than a complete tear-off. This is because it eliminates the labor and disposal costs associated with removing and disposing of the old shingles.
- Time-saving: Overlaying a metal roof is generally a quicker process than a tear-off installation. With an overlay, there is no need to remove the old shingles, reducing the time required for the installation.
- Weather Protection: One of the benefits of overlaying a metal roof is that it provides an extra layer of protection to your home. The metal roof acts as a shield against weather elements such as rain, snow, and hail, while also offering better resistance to wind damage.
Considerations Before Overlaying:
- Structural Integrity: Before considering an overlay, it is essential to ensure that the existing roof structure can support the added weight of the new metal roof. Metal roofs are generally heavier than asphalt shingles, so it is crucial to consult with a professional roofer or structural engineer to assess the load-bearing capacity of your roof.
- Existing Roof Conditions: The condition of the existing asphalt shingles is another crucial factor to consider. If the shingles are in poor condition, with significant damage or deterioration, overlaying is not recommended. The new metal roof will not fix the underlying issues and may exacerbate any problems.
- Leveling and Ventilation: It is important to ensure a level surface for the metal roof installation. Any areas with sagging or unevenness should be addressed before overlaying. Additionally, proper ventilation is necessary to prevent moisture buildup between the old shingles and the new metal roof. Inadequate ventilation can lead to issues such as mold or premature deterioration of the metal roof.
While it is possible to overlay an existing asphalt shingle roof with a metal roof, it is important to consider several factors before making the decision. The structural integrity of the existing roof, the condition of the shingles, and the need for leveling and ventilation are all crucial considerations. Consulting with a professional roofer is highly recommended to assess whether an overlay installation is feasible and appropriate in your specific situation. With careful planning and expert guidance, overlaying old asphalt shingles with a metal roof can be a cost-effective and efficient way to upgrade your roof and enhance its durability.