This roofing method entails overlaying a new shingle roof on an existing one. In addition, the other shingles can be of two or more layers. A homeowner can use this re-roofing method to save money. Apart from their cost efficiency, they look good.
Can you Add a Second Layer of Roof Shingles to an Existing Roof?
As a homeowner, you can add new shingles to the old shingles. We’ll look at why most homeowners choose this roofing method. Also, we take a look at why overlaying shingles isn’t good.
You can’t overlay the shingles with metal or wood. For example, you shouldn’t mix materials such as asphalt shingles and cedar shakes.
A second shingle layer decreases your new roof’s integrity and lifespan. Degradation happens because manufacturers don’t design the shingles to hold multiple layers. The extra heat and moisture on the first shingle layer also age it faster.
Why do Some Homeowners Choose to Add Additional Layers?
Adding extra shingle layers doesn’t make your new roof shingles more waterproof. On the contrary, double-layer shingles create additional problems.
Some homeowners pick this roofing method because they’re cheap and save money. Letting the old shingles stay avoids labor-intensive and messy tear-off steps.
In some situations, leaving the old shingles in place saves the roof contractor’s time. The contractor will only need to do some little clean-ups. Thus, a homeowner won’t need a tear-off.
Also, overlaying shingles is convenient since damaging the landscape is minimal. You can damage the landscape or flowers when overlaying shingles.
Avoiding the tear-off process enables the roof to do the installation quicker. As long as your current roof doesn’t have leaks, the installation happens faster.
Moreover, the roofing contractor skips the underlayment installation to save time. Skipping the underlayment installation cost saving.
Choosing Between a Roof Overlay vs. Tear-off
Tearoffs: Reliable and Long-Lasting
This complete roof replacement method happens by tearing off your old roof. After doing so, you’ll install a new roof.
Advantages
All-new material. You’ll replace all the roof parts with new material with a roof tear-off. So if your underlayment or decking is deteriorating, you’ll solve it. Also, your roofer can check and repair any leaks. Doing so protects your home from rot and mold.
Upgrade options availability. Construction companies don’t go for high-quality materials always. For that reason, if you’ve bought an old house, you can upgrade its roof.
Greater durability. A roof built from all-new materials lasts longer, unlike older roofs. That’s because older roofs have been susceptible to harmful elements for decades.
Longer lifespan. New and properly installed shingle roofs last between 20 and 30 years. A longer lifespan means the roof can outlast an overlay shingle by a decade.
Increased property value. A new roof adds about $10,000 to your house’s resale value. Also, it makes your selling point stronger. Thus, a tear-off is brilliant if you plan to resale the house soon.
Disadvantages
Higher costs. On average, tear-off roofing jobs cost 25 percent more than overlay roofs. Also, you’ll need extra labor to tear off and replace your existing roofing material. In addition, you’ll need to properly dispose of the old roofing material, which adds up to the cost.
Overlays: Budget-friendly and Convenient
With this alternative, you install the new shingles over the other existing shingles. This roof replacement is only possible if you’ve never overlaid your roof before.
Advantages
Lower costs. Overlays cost less compared to placing new shingles on old ones. The low prices come about because of low labor costs. Also, you’ll save more since roofing contractors don’t need a dumpster. And deal with the existing disposal regulations too.
Shorter work timeline. A roofer can finish installing an overlay sooner compared to tear-offs. Thus, you won’t have to spend some extra days out of your house. As a result, you’ll save more and be stress-free.
Less risk. Unlike a complete roofing replacement, it’s hard for things to go wrong.
Disadvantages
Lower quality. The existing roof must be in optimal conditions to rely on an overlay like a tear-off. To properly examine your roof, a roofer must remove the shingles.
Shorter lifespan. New shingles overlaid on a rotting decking and damaged shingles don’t last. On average, overlays can last for around 16 years.
Additional weight. An entire shingle’s weight adds more stress to your roof decking. Also, the weight affects your home’s structure. An overlay isn’t viable if you have an old or structurally unsound house.
Less visual appeal. Your old roof shingles have endured a fair share of wear and tear. Unfortunately, wear and tear leave your roof curling, uneven, and torn.
Tricky to maintain. Multiple layers of shingles add more complexity to shingle roofs. For that reason, tracking down the origin of a defect becomes harder. When a leak comes up, water moves between the layers of shingles. The water leak hides any source of defect on your shingle roof.
How Long does the Second Layer of Shingles Last on a New Roof?
A shorter lifespan it is! When you lay new shingles over existing shingles, they won’t last. Also, the same happens when you’re laying asphalt shingles over a rotting roof decking.
Moreover, a shingle roof with double layers retains more heat. The extra heat speeds up the deterioration of your existing roofing. On average, roof overlays last for 16 years.
The Expected Lifespan of Asphalt Shingles is 15 to 30 Years
Asphalt roof shingles are the most known and sold among the existing roofing material. That is today. Roofing contractors install these roofing shingles on 80%+ of new homes today.
Apart from their affordable nature, shingle roofs have outstanding aesthetics. The shingle roofs average about $69 to $149 per square. Also, this roofing type has a warranty of 25 years.
A mixture of asphalt coating and fiberglass creates durable layers of protection from
- Wind
- UV rays
- Rain
When sun rays hit the shingles, the asphalt in them softens. Moreover, the asphalt softening bonds the shingles, forming a watertight seal.
Architectural Shingles, a Premium Type of Asphalt Shingle, can Last 25 to 30 Years
Architectural shingles are three times thicker and are denser than standard asphalt shingles. For that reason, Architectural shingles are a more resilient roof.
In addition, architectural shingles warranties prove how this roof structure is durable. Although asphalt roof warranties vary, some stretch beyond 30 years. Architectural shingles are extra expensive at $249 to $399 compared to three-tab roofs. But, most homeowners consider them attractive.
Their multiple laminated layers enhance their durability. They also allow the roof to mimic expensive roof materials’ patterns and textures. The expensive roof materials are tile, wood, and slate roofs. Although such luxury designs aren’t pricey, they offer high-end aesthetic looks.
Wood Shingles can Last up to 30 Years but Require Annual Upkeep
Manufacturers prefer cedar for wood shakes and shingles. They do so because cedar it’s insect and rot-resistant. Over time, the wood shingles weather, forming soft silvery-gray aesthetics.
When the weathering of the shingles happens, they become stylish. But, they’re well-suited to the cottage and Tudor-style houses with steep-pitched roofs.
For wood shingle roofs, you’ll pay $249 to $599 per square. To keep the shingle roof in better condition, inspect it annually. When you notice some split shingles, replace them promptly.
Well-maintained wood shingle roofs last between 15 and 30 years. But the roof’s durability depends on the quality of its shakes or shingles.
Wood shingles have natural aesthetics and are low-cost. But, they’ve some drawbacks. Since they’re natural, it’s common to see split or warped shingles during installation.
Also, chances are, you’ll encounter some disfigurement after installation. Such wood shingle defects cause pop-ups and leaks.
Is it Better to Remove Old Shingles?
When it comes to re-roofing, overlaying shingles has become an old method. While repair jobs are convenient and cost-efficient, it’s a bad idea. Whether repairing a section or replacing the roof, remove the old shingles. It would help pull down the old shingles when putting on the new ones.
Can you have 3 Layers of Shingles?
It isn’t advisable to have three asphalt shingle layers on your roof. Moreover, you can only have two-layer asphalt shingles on a roof in most states. That’s because the policy considers fire safety precautions. But, to date, some states have houses with roofs with three or more layers.
Problems with Two Layers of Shingles
Installation Problems
Problems from second-layer shingles come about during installation. The first installation of asphalt shingles happens on a flat, smooth surface. Adding the second shingle layer isn’t an option during the initial installation.
Since the extra layer exists on the old layer, the surface is gap-filled and bumpy. The process makes the shingles extra hard for accuracy and mounts safety.
Damage to the Roof
A roofing contractor inspects the joint areas during the shingle roofing material teardown. These roof joints hold together the rest of your home. Teardowns allow a reputed contractor to find defects in the underlayment and decking.
Without that inspection, damage to the roof might go unnoticed. The extra shingle layers can also cause leaks. You’re asking for trouble when you install an extra shingle layer. That’s because the extra layer increases leakage chances and other damages.
Two-layered shingles cause severe defects down the line. You should consider the additional weight your shingle roof would endure. Shingles weigh between 349 and 449 pounds per sq.
Cost
The main benefit of multilayer shingles on top of older ones is cost-saving. When you install such layers, you skip the tear-off process. Thus, saving money.
All that re-roofing process seems a lot. The multilayer re-roofing method can cause additional repair costs. Also, this re-roofing method decreases your home’s value.
Conclusion
Although multiple shingles layers are cost-effective and beautiful, they don’t last long. Of the two types of shingle layers, none goes past 30 years. Thus, prepare for early replacements if you plan to adopt this re-roofing method. In addition, I’d recommend you pick other roofing materials or methods.