Installing New Roof Shingles Over Old Ones: Is It Advisable?

Water is the main foe of your household and it is crucial for your roof to prevent it from entering. Maintaining and taking care of our roofs is well-known to be a crucial task, but it can also be one of the costliest responsibilities of being a homeowner.

The Possibility and Implications of Overlapping New Roof Shingles

Understanding the Basics: Can You Install New Roof Shingles Over Old?

It is common to seek methods for cost-saving while carrying out essential roof upkeep and fixes. When dealing with an asphalt shingle roof that is nearing its lifespan, you may consider the possibility of attaching new shingles over the existing ones as a means of saving money.

The response to this inquiry is indeed ‘affirmative.’ However, prior to embarking on the task of overlapping fresh shingles on top of existing ones, there are several factors that roofing professionals typically discourage from utilizing this approach.

New Roof Shingles

In this piece, we will examine the various factors to consider when deciding between removing your existing shingles or installing new ones, in order to make a well-informed choice for your roof’s maintenance.

Can You Put New Roof Shingles Over Old Ones?

If the idea of installing new roof shingles on top of your existing shingles has crossed your mind, you may be questioning its effectiveness in the long run.

Although it is possible to place new shingles over existing ones, it may not be the best choice for a variety of reasons that will be discussed in the following section. Initially, we will examine the reasoning behind adding new shingles on top of old ones.

Why Homeowners Consider Layering New Roof Shingles

The main reasons for individuals to opt for placing new shingles on top of existing ones are typically to save money and minimize inconvenience.

If you do not need to remove the existing shingles before installing a new layer, it can save you money on labor if you have hired someone to do the job, or save you time if you are doing the project yourself.

The Practicality of Skipping Shingle Removal

When considering the time involved in removing the previous roofing materials, it typically accounts for around 30% of the work time at the job location, excluding the time spent on site clean-up. By leaving the old roofing intact, the roofing team can immediately begin installing the new shingles.

One advantage of keeping your shingles in place is that it protects your roof from the elements while the work is being done. However, cost and time savings are typically the main reasons why homeowners choose to forego removing their old shingles.

Why You Shouldn’t Put New Roof Shingles On Top Of Old Ones

When a roofing contractor provides an estimate for your roofing project, it is common for them to suggest removing your current shingles and starting anew. There are instances where certain contractors may refuse to take on the job if you insist on keeping the old shingles in place.

One may assume that these sales representatives are solely motivated by earning the highest profit from the project. However, the reality is that there are multiple factors that make it a more advantageous long-term decision to first remove old shingles before installing new ones.

Winnipeg Roof
Evaluating the Long-Term Impact

The Importance of Inspecting the Roof Deck

In order for roofing experts to properly examine your roof deck and underlayment, it is necessary for them to remove the current layer of shingles. The roof decking and underlayment serve as additional layers of defense for the interior of your home, situated beneath the shingles.

Roofing contractors can only determine the presence of spongy, soft, or rotting areas on your roof decking by removing the shingles. Neglecting to remove the old shingles will keep both you and the roofers unaware of any deterioration in the underlayment that could compromise its ability to protect against moisture.

The intended use of shingles involves nailing them onto a flat and even underlayment surface. However, when installing new shingles over existing ones, the added layer of material between the new shingle and underlayment can weaken the nail’s grip. This may increase the risk of shingles being blown off the roof.

Challenges with Shingle Installation Quality

Furthermore, the presence of your previous shingles will result in an irregular and lumpy base on which you plan to place new roof shingles. As a result, the new shingles may not lie completely flat on your roof, which could potentially compromise the level of protection that your new roofing material offers for your house.

We understand that roofing projects can be costly. It is common to try to save money when replacing a roof, and the possibility of layering new shingles over old ones may be tempting.

The Inevitable Future Costs

In the end, you are simply postponing the inevitable. If you plan on staying in your house for many years, it is likely that you will still be residing there when the roof needs to be replaced. This will require the roofing company you hire to remove and dispose of two layers of shingles, instead of just one.

Layering shingles may seem like a cost-effective solution, even if you have no intention of living in the house permanently. However, as we will discuss later, it can ultimately decrease the value of your home and deter potential buyers.

Roof Replacement

Additional Considerations Before Layering Shingles

The Risk of Trapped Moisture and Growth

Having moss or algae growth on the current shingles of your home can have a detrimental effect on the lifespan of your new shingles.

These growths, no longer exposed to the sun and elements, can become trapped between the two shingles and may cause the new shingles to deteriorate faster than if the first layer was removed.

Addressing Underlying Roofing Issues

When new shingles are added over old shingles due to a leak or other problem, it is simply a temporary solution rather than addressing the root issue. In cases where there has been water infiltration in the roofing system, it is likely that the decking and underlayment have been damaged.

Given that the inspection and roof replacement of these system components cannot be properly done without first removing the existing shingles, simply placing new shingles on top of the old ones may provide temporary relief but will not effectively address the underlying roofing issues.

The individual pieces of shingles may not appear to have much weight, but when combined, they can significantly increase the weight of your roof. Generally, a square of roofing material, which is equivalent to 100 square feet, can weigh anywhere between 250 and 400 pounds.

By placing an additional layer of shingles over the preexisting ones, you effectively increase the weight being supported by your structure. This extra load can place strain on your roof, potentially causing further damage to the sheathing if your house was not constructed to withstand it.

The Weight Factor on Your Roof Structure

The possibility of your roof sagging due to adding more weight beyond the initial shingles layer depends on the construction of your home and its ability to support such weight. If you choose to add another layer of new roof shingles, it is crucial to ensure that the structure can withstand the additional weight to avoid any structural issues.

Compliance with Local Building Codes

Before proceeding with installing new shingles over an existing layer of shingles, it is important to thoroughly research the building codes and regulations in your local area. This will ensure that you are in compliance and avoid any potential issues.

Depending on the location, certain guidelines may exist regarding the number of roof layers permitted on a structure. It is possible that a second layer of shingles may be allowed in some places, while others may only allow for a single layer of shingles.

It is important to consider the impact of adding an extra layer of shingles on the resale value of your home, regardless of your current plans to sell. While potential buyers may be concerned about the future cost of removing two layers of shingles, it is worth contemplating the potential benefits of this upgrade. This is because replacing the roof would require additional expenses for the removal of two layers of shingles.

In addition, it could suggest to purchasers that the roofing project was completed by a homeowner instead of a skilled team, causing them to feel anxious about the possibility of the installation being done incorrectly.

Impact on Resale Value and Buyer Perception

In the long run, placing new shingles on top of existing ones may deter potential buyers in the event that you decide to sell your house. Hence, if you anticipate the possibility of relocating in the future, this is a crucial aspect to consider in your decision-making process.

Warranty Considerations with Layered Shingles

Before installing new roof shingles over old ones, it is crucial to take into account the possibility of voiding the manufacturer’s warranty. This is a significant concern that should not be overlooked.

According to shingle manufacturers, the warranty may be deemed void if shingles are placed on top of current ones instead of being installed directly onto the underlayment.

Alternatives and Professional Services in Winnipeg

Exploring Different Roofing Material Options

Residential homes in Winnipeg Manitoba typically use asphalt shingles as their primary roofing material, however, there are other options available for shingles to be incorporated into your roofing system. These materials include clay, metal, and slate.

When working with dense materials such as clay and slate, it is not recommended to add another layer on top of the existing one. This is especially important for steeply sloped roofs, as it can lead to dangerous roof conditions. While there are some areas that allow for two layers of asphalt shingles, it is generally prohibited to have more than two layers of this material.

Choosing Kenava Roofing for Your Needs

At Kenava Roofing, we take pride in providing the most competitive rates in Winnipeg and the surrounding areas in Manitoba for top-notch roofing solutions. We understand that roof repairs or replacements can be inconvenient, so we make it our mission to ensure a stress-free and straightforward experience for our customers.

Our carefully chosen team members possess expertise, honesty, and strong work ethic, while our customer service representatives strive to exceed expectations and provide a seamless and pleasant collaboration with us.

Get in Touch for a Free Estimate on New Roof Shingles

If the time has come for you to replace or repair your shingles and roof in Winnipeg, then you have found the perfect spot. If there are any inquiries about our services or the procedure of replacing your roof, or if you would like us to provide you with a complimentary estimate, please don’t hesitate to reach out to us today via our contact page

FAQ on New Roof Shingles

1: Is it possible to install new roof shingles over existing ones?

Answer: Yes, it is technically possible to install new roof shingles over the existing ones. However, this method is generally discouraged due to various factors such as the inability to inspect the underlayment, potential for increased roof weight, and the possibility of voiding the manufacturer’s warranty.

2: What are the potential disadvantages of installing new roof shingles over old ones?

Answer: There are several potential disadvantages:

1. Inability to inspect underlayment
Roofing contractors need to remove the current layer of shingles to properly examine your roof deck and underlayment.

2. Increased roof weight
The combined weight of two layers of shingles can significantly increase the weight on your roof, potentially causing structural damage.

3. Voiding the manufacturer’s warranty
The warranty may be deemed void if shingles are placed on top of current ones instead of being installed directly onto the underlayment.

3: Does installing new roof shingles over old ones affect the resale value of a house

Answer: Yes, it could potentially decrease the resale value of your home. Potential buyers may be concerned about the future cost of removing two layers of shingles and may question the quality of the installation.

4: Are there any local regulations about installing new shingles over old ones?

Answer: Yes, local building codes and regulations may have guidelines regarding the number of roof layers permitted on a structure. It’s important to research these before proceeding with the installation.

5: What is the lifespan of new roof shingles?

Answer: The lifespan of new roof shingles can vary greatly depending on the material used, the quality of the installation, and the weather conditions in your area. However, on average, asphalt shingles can last between 15 to 30 years.

6: What are some signs that my shingles need replacing?

Answer: Some signs that your shingles may need replacing include curling or buckling, missing shingles, shingle granules in the gutters, and visible wear and tear. If you notice any of these signs, it’s best to consult with a professional roofer.

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