A roof replacement is a big investment for homeowners, and when the roof begins to show its age, the first thought most homeowners have is, “How much is this going to cost?” Looking for ways to reduce costs does not make a person cheap; it makes them smart. However, when we consider the importance of our roof in keeping our homes (and us) safe, cheaper isn’t always better.
After receiving several quotes for a new roof, some homeowners may discover one that stands out as a much cheaper option, and it’s the one that mentions adding a second layer to the existing shingles. At first, it seems like the choice that will save the homeowner the most money. With decreasing labor costs and the elimination of debris removal, adding a second layer appears to be a viable option. But is it a wise choice? Will homeowners really save money in the long run?
If you find yourself facing this exact decision, it’s important to understand what adding a second layer to your roof really means. Often referred to as an overlay, adding a second layer of shingles to the existing roof is sometimes acceptable, but more often it’s not recommended. Together, we’ll learn about the risks of placing a second layer of shingles on a roof and discover why, when the time comes, a proper roofing installation delivers better long-term value. First, let’s discover what it means to add another layer of shingles to an asphalt shingle roof.
What Does It Mean to Add a Second Layer of Shingles?
Asphalt shingle roofs are among the most common roofing systems for residential homes across the United States. Covered in tiny granules, shingle roofs protect against rain, wind, and UV exposure, and withstand changing weather conditions with each season. An overlay is exactly what it sounds like. Rather than removing worn-out shingles, a contractor installs a new layer of shingles directly over the old ones, creating a multi-layered roof.
In many areas, building codes limit the layers of shingles allowed on a roof. Building codes in Michigan generally allow up to two layers on residential roofs, provided the existing layer is in good enough condition. While this two-layer approach eliminates the tear-off process and is legal in some situations, it doesn’t necessarily mean it’s the best choice. But before we get into the problems with adding a second layer of shingles to roofs, let’s take a minute to appreciate why homeowners would consider it in the first place.
Why Homeowners Consider Adding a Second Layer
Mentioned at the beginning of the article, the biggest reason homeowners consider adding a second layer of shingles to their existing roof is cost, but another attractive benefit is convenience. Listed below are the reasons homeowners may consider over-layment rather than removal and replacement:
- Lower initial cost of roofing installation. Avoiding additional labor costs and removal fees can save homeowners thousands of dollars at the time of installation. For homeowners with budget constraints, adding a second layer can be an appealing short-term solution.
- Without the need to remove the old roofing materials, overlayment allows the job to be finished much faster than a full replacement. Quick and convenient, adding a second layer comes with less disruption, noise, and mess.
- Adding a second layer of shingles to a damaged roof provides temporary protection against rain and wind when a homeowner doesn’t have the resources to replace the roof immediately.
These benefits are hard to ignore when homeowners need to repair a damaged roof, but funds are low. However, the project’s price tag is only part of the story. Beyond budgets, there are only a few scenarios when a second layer of shingles might be acceptable.
When Is a Second Layer of Shingles Acceptable?
There are only a few situations where overlaying a second layer of shingles is an acceptable option for roof repair. These limited scenarios include:
- When a roof has only one layer of shingles that are in good condition, meaning they are not showing any signs of deterioration, an overlay may be possible.
- In addition to existing shingles being in good condition, the roof deck must also be structurally sound. In this circumstance, the roof must have no existing leaks, rotting, or sagging.
- Homeowners on a budget, especially those planning to sell their home in the near future, may prioritize short-term savings over maximizing the long-term performance of a fully replaced roof.
In all of these situations, local building codes must also permit adding a second layer of shingles. However, even then, most professional roofers will still almost always recommend a full replacement for the best long-term performance and protection.
Why Adding a Second Layer of Shingles Is Often Not Recommended
Of course, the potential to save a little cash makes overlaying shingles an attractive option, but it does come with disadvantages. Often outweighing the benefits, these drawbacks can lead to substantial problems, including:
Undiscovered Issues: Without removing the old roof, it is impossible to inspect (or repair) problems beneath the shingles. When contractors perform a complete roofing installation, they closely inspect the roof deck for rot, water damage, soft spots, structural deterioration, and ventilation issues, among other things. When problems are covered up, they become much harder to find later on.
Adding Weight: An asphalt shingle may not seem like a weighty object, but cover an entire roof with them and they’re heavy! While many homes can support the added load, it becomes concerning in certain regions. In Northern Michigan, where snow piles up through the winter months, adding another layer of shingles places extreme stress on the rafters and roof decking. For underlying structures that are already compromised, the extra weight becomes a liability.
Reduced Lifespan: Contrary to what many homeowners believe, overlaying a second layer of shingles on the roof is not as long-lasting as installing them on a clean roof deck. Placing new shingles over old ones, on average, reduces the lifespan of the new shingles by 20 to 30%. In addition to a shortened lifespan, the uneven foundation for the new shingles accelerates wear and can trap heat, accelerating the aging of the asphalt.
Inspection and Repair Complications: When asphalt shingles are layered on one another, leaks become difficult to detect and repair. Water can easily travel between layers, slowly making its way indoors, and making it difficult to pinpoint the actual problem. When problems arise, multiple layers make repairs extremely difficult and increase labor costs.
Expensive Replacements: When the time comes for a full roof replacement, homes with multiple layers of shingles incur higher labor and disposal costs than single-layer roofs. This is probably one of the most overlooked disadvantages. What many homeowners do to save money upfront ends up costing more in the long run.
Poor Performance: When shingles are overlaid onto an existing layer, the valleys, edges, and transitions are harder to seal, increasing the risk of leaks during moderate to heavy rain or in the event of an ice dam.
Reduced Energy Efficiency: The addition of another layer of shingles on the roof can trap heat in the home, making it much warmer in the summer, increasing energy consumption and utility costs.
Warranty Issues: Most shingle manufacturers have specific requirements regarding roof conditions and installation methods. If these guidelines and recommendations are not followed, the manufacturer can limit or even void warranties, and homeowners lose the protection they thought they paid for. Homeowners should always review warranty details before deciding between a full roofing installation in Traverse City and an overlay.
As you can see, what might feel like a bargain at first can quickly become a more expensive choice in the long run. Most of the time, a full roof replacement offers better long-term value.
Why a Full Roof Replacement Is the Better Long-Term Value
A full roof replacement involves tearing off the old shingles, all the way down to the roofing deck. Roofing installation done this way offers many advantages that help protect your home. These advantages include:
Thorough Inspection: Without removing the old shingles, roofers cannot perform a thorough inspection. When old roofing material is removed, they can inspect and repair any deck damage and flashing issues, add appropriate new underlayment, and enhance ventilation if necessary before the new shingles go on.
Enhanced Performance: Removing old roofing materials and starting fresh with a properly installed roof gives the roofing system the best opportunity to perform as designed, providing premium protection against water damage and resistance to wind, hail, snow, and ice.
Maximum Longevity: New shingle roofs should last anywhere from 25 to 30 years, and even longer with proper care and maintenance when using premium materials. In almost every case, a roof installed on a clean deck provides better protection for much longer than installing an overlay on old shingles.
Warranty Coverage: By following all manufacturer recommendations and working with a professional roofing contractor in Traverse City who stands beyond their work, homeowners get the full benefit of manufacturer and workmanship warranties.
Enhanced Aesthetics and Value: A complete roof replacement yields a much more uniform and attractive appearance than one with the old shingles left in place. Providing an improved, clean finish, full replacements not only enhance the home’s curb appeal but also boost its resale value.
Lower Long-Term Costs: By now, we can all agree that cheaper doesn’t always mean better. Even though the initial investment for a full roof replacement is higher, the protection, performance, and longevity help homeowners avoid costly repair bills and premature replacement.
Although a shingle overlay offers short-term savings, a full roof replacement offers the best long-term value. With consistent protection, performance, and peace of mind, it’s easy to see the advantages of replacement over an overlay.
Looking Beyond Today’s Savings
Understandably, most of us are looking for a way to save money these days, and adding a second layer of shingles seems like an easy way to do just that. For homeowners in very specific situations, a shingle overlay may be a viable option, but for most, it only creates headaches and higher costs down the road. The potential savings of today lead to undetected damage, added weight that stresses the structure, and much more complex and expensive future repairs.
With a complete and full roof replacement, homeowners can ensure their investment provides the best protection and long-term value. Although the initial expense for roof replacement is higher, the opportunity to address underlying issues, enhance performance and aesthetics, and extend the roof’s lifespan makes it a more valuable choice. If your roof is nearing the end of its life, schedule an inspection with a trusted professional today and start preparing for the best solution to keep your home protected for years to come.