Your roof is the first line of defense against everything nature throws at your home—rain, wind, snow, and even the sun’s relentless heat. When it comes to installing shingles, many homeowners face a tempting choice: simply layer new shingles over the old ones to save time and money. But is this shortcut worth the potential risks? While adding layers of shingles might seem like a quick fix, it can lead to costly issues down the road, impacting the integrity and lifespan of your roof. Let’s break down the pros and cons to help you make the best decision for your home.
Understanding the Basics: Local Building Codes
The number of layers of shingles allowed on a roof largely depends on the city you live in and the building codes enforced by your local authorities. Most city codes permit two to three layers of shingles on a roof. However, it’s not uncommon to find instances where as many as five layers have been allowed.
But just because it’s allowed doesn’t mean it’s advisable. Adding multiple layers might seem like a cost-effective solution in the short term, but it can lead to significant issues down the line.
The Problem with Layering Roofs
One of the main problems with having multiple layers of shingles on your roof is the risk of leaving an old, deteriorating roof system underneath a seemingly perfect new one. This isn’t just a cosmetic issue; it has serious implications for the longevity of your roof.
Here’s why:
- Deterioration of the Underlying Roof: Even with a new layer of shingles on top, the old roof underneath continues to deteriorate. This ongoing deterioration can significantly impact the lifespan of the new roof layer. In essence, you might install a shingle system that’s designed to last for decades, but due to the compromised foundation underneath, its actual lifespan is cut in half.
- Voiding Warranties: Many shingle manufacturers provide long-term warranties on their products. However, if a new shingle system is installed over an old, deteriorating one, it often voids the warranty. The reasoning is simple—an unstable foundation compromises the performance of the new shingles, making them more prone to issues like leaks and accelerated wear and tear.
- Increased Weight: Each additional layer of shingles adds weight to your roof. While a single layer might not be a problem, multiple layers can strain the structure of your home, potentially leading to sagging or even structural damage over time.
Why Do People Choose to Layer Roofs?
Despite the risks, some homeowners opt to layer new shingles over old ones primarily to save money. The logic is straightforward—why spend more on removing the old shingles when you can just cover them up? However, this decision often leads to more significant expenses in the long run.
In the past, layering shingles was more common, but as roofing companies have become more knowledgeable and homeowners more informed, this practice has become less popular. Reputable roofing companies now strongly advise against it, recommending instead a complete tear-off before installing a new roof system.
The Inevitable Need for a Fresh Start
Even if layering shingles works temporarily, it’s usually not a permanent solution. Eventually, you’ll need to remove all the layers and start from scratch. Starting with a fresh substrate ensures that the new roofing system has a solid foundation, free from the issues that come with deteriorating materials underneath.
In Summary
So, how many layers of shingles can you have on your roof? While local codes might allow up to three layers, we strongly recommend against it. The potential for underlying deterioration, voided warranties, and structural strain outweighs the short-term cost savings. Instead, it’s wiser to remove the old shingles and start fresh with a new, robust roofing system.
If you’re considering a roof replacement or have questions about your current roof’s condition, contact us today. We’re here to help you make the best decision for your home.
