Should You Install a New Roof Over Old Shingles: Pros and Cons

When it comes to deciding whether to put a new roof over old shingles, there are a few things to consider. If the conditions are favorable, it may be a good option for you. Here are some factors to keep in mind:

Quality of the existing shingles: If the old shingles are in good condition and have not reached the end of their lifespan, they can provide extra insulation and protection for the new layer of shingles.

Local building codes: Check with your local building department to ensure that placing a new roof over old shingles is allowed in your area.

Weight-bearing capacity of your roof: Adding another layer of shingles can add significant weight to your roof, so it’s important to ensure that it can support the additional load.

Cleanliness of the existing roof: The old shingles must be free of debris, mold, or algae to prevent any issues with the new layer of shingles adhering properly.

If the above factors are favorable, installing a new layer of shingles over old ones can save you time and money compared to tearing off the old roof. Plus, you can use the existing shingles as a guide for the installation of your new shingles. However, it’s important to weigh the pros and cons carefully before making a decision.

Benefits of Layover Roofing

Laying new shingles over old ones could be a viable option for homeowners looking to replace their roofs. One main advantage of layover roofing is that it is less difficult and time-consuming than doing a complete tear-off and installation of a new roof. You can use the old shingles as a guide for the installation of the new ones, reducing the amount of prep work needed. The process also saves money by limiting debris disposal costs and labor expenses. Another advantage of layover roofing is that it can extend the life of your existing roof. The additional layer of shingles offers an extra barrier against the elements, including wind and sun damage, reducing the wear and tear on the underlying shingles. Moreover, it gives extra insulation, saving you money on heating and cooling bills.

Factors to Consider Before a Layover Installation

Before deciding about the layover of shingles on an existing roof, certain factors must be considered. One is whether the existing roof is capable of supporting the added weight of the shingles. If the first layer of shingles is in good condition, it usually is, but if it is old and worn, it may not be strong enough to support the new layer. Another factor is the building codes, as some jurisdictions have limitations regarding layover roofing to a single layer of shingles only. Areas experiencing extreme temperatures or having high exposure to UV radiation may demand a complete clear-out of the old shingles for a functional transition to better environmentally friendly roofing materials.

Pros and Cons of Adding a New Roof Over Old Shingles

There are several pros and cons to consider about layover roofing versus a complete tear-off and installation: Pros:

• Less labor-intensive and time-consuming, reducing installation costs
• Adds an extra layer of protection for the underlying shingles
• Improves insulation and energy-efficiency of the house
• Reduced mess and waste material

Cons:

• Building codes: Some cities or states restrict the number of shingle layers allowed, hence making it against the law
• Shorter durability compared to complete tear-off installations
• Risk of not covering rotted or damaged wood decking below the old shingles
• The second layer of shingles may alter the look and value of your house externally, reducing it in some cases

Preparation and Inspection of Old Shingles for Layover

Before installing the new layer of shingles, it is essential to do a thorough inspection of the existing shingles. Check that all the shingles are intact, that there is no wood rot, and that they are firmly attached. The old shingles should be flattened or removed to provide a smooth surface. The inspection will ensure that any damages are repaired before a new layer of shingles is added to the old ones.

The Installation Process of a Layover Roof

The process of installing a new layer of shingles over the old ones does not require the removal of the first layer. First, the installer removes any potentially problematic nails, which may cause issues later, then the process starts by cutting and fastening starter shingles at the eaves and rakes. After that, new shingles are added on top of the old ones, extending the life of the roof by several years. It is crucial to check for a proper drip edge around the perimeter of the roof, ensuring that water cannot seep into the newly shingled layer. End with trimming the overhanging shingle edge and set the ridge caps in place on the roof peak.

Understanding the Cost of a Layover Roof vs Tear-Off Roof

The cost of layover roofing varies depending on the number of old shingle layers, the roof pitch, and the size of the area being re-roofed. Installation of a new layer of shingles requires less overhead labour costs making it less expensive in comparison. Keep in mind that a tear-off would typically be more expensive due to labour-intensive procedures, removal costs and dump fees.

Maintenance and Longevity of a Layover Roof

Maintenance of a layover roof is not much different than what is required by the new roof. Keeping the roof free of debris, clearing gutters, and performing annual inspections can extend the life expectancy. But it is important to note that a layovered roof will wear faster than a new installation, requiring more eventual replacements. The roof may have a shorter lifespan than a complete tear-off and installation, depending on weather conditions. In conclusion, installing new shingles over an existing roof has its advantages and disadvantages. But if the conditions are favorable, layover roofing can be a cost-effective and practical approach to address roofing issues that do not require a complete tear-off. Nevertheless, it is essential to have thorough preparation procedures and inspections that guarantee a successful and safe installation of your new roof.