When faced with the prospect of roof replacement, some homeowners consider installing a new roof directly over their old one as a way to save time and money. While this may seem like a quick and cost-effective solution, the old adage, “putting new product over old problems doesn’t solve your problem,” rings especially true in roofing. The issues underlying your old roof won’t simply disappear—they’ll likely resurface, leading to more extensive and expensive repairs down the line. Here’s why it’s always best to do the job right the first time with a full tear-off.
Missed Opportunity to Inspect the Sheathing
One of the most significant drawbacks of layering new shingles over old ones is that it prevents you from inspecting the sheathing beneath the original roof. Sheathing, the layer of wood or plywood between your roof’s structural components and the shingles, plays a crucial role in the overall integrity of your roof. Over time, moisture can seep through the shingles, causing water damage or mold growth in the sheathing.
If you skip the full tear-off and install new shingles on top of the old ones, you miss the opportunity to identify and address these issues. Mold, for instance, can continue to grow and spread, potentially causing not only structural damage but also health problems for the inhabitants of the home. By not addressing these problems early, you may face even greater expenses in the future when the damage becomes more severe and widespread.
Check out this video of one of our roof inspections.
Added Weight Can Lead to Structural Issues
Another critical concern with installing new shingles over old ones is the additional weight it adds to your roof. A single layer of asphalt shingles typically weighs between 200 and 250 pounds per square (100 square feet). When you add a second layer, you’re doubling the load on your roof’s structure. This increased weight can strain the supporting elements of your roof, such as the trusses and rafters, potentially leading to sagging, cracking, or even collapse over time.
In some cases, local building codes may allow for a second layer of shingles, but this doesn’t necessarily mean it’s the best choice for your home. The age and condition of the existing roof, as well as the design and strength of your roof’s framework, must be carefully considered. An overloaded roof is more vulnerable to damage from snow, ice, and high winds, which could lead to costly repairs or even catastrophic failure.
The Benefits of a Full Tear-Off
Opting for a full tear-off instead of layering new shingles over old ones provides several important benefits. First, it allows your roofing contractor to thoroughly inspect the sheathing and other underlying components for any signs of damage. Addressing issues like rotting wood, water damage, or mold at this stage ensures that your new roof is built on a solid, healthy foundation.
Second, a full tear-off eliminates the risk of overloading your roof’s structure with excess weight. Your new roof will be lighter and more resilient, reducing the likelihood of future structural issues.
Lastly, starting fresh with a new roof allows for better adhesion of the new shingles, leading to a longer-lasting and more durable roof. This approach may have a higher upfront cost, but it’s a wise investment that can save you money in the long run by preventing future problems.
Conclusion
In roofing, as in many other areas of home improvement, it’s crucial to do the job right the first time. Installing new roof over old shingles may seem like a shortcut, but it often leads to more problems down the road. By opting for a full tear-off, you ensure that your new roof is built on a solid foundation, free from hidden damage, and capable of protecting your home for many years to come. Don’t cut corners—invest in quality, and enjoy the peace of mind that comes with knowing your roof is in the best possible condition.