Pros and Cons of Roofing Over Existing Shingles: A Homeowner’s Guide

Posted on June 2025

Have you ever noticed your roof looking a little worn? Maybe a few shingles are curling or there are some dark patches after a crazy storm? If yes, then you are probably from the homeowners population who wonder  "Do I need a whole new roof, or can I just go over the old one?"

According to the National Association of Realtors, roofing is one of the top five most valuable upgrades you can make to your home. But full roof replacements are real pocket burners. So, it is no surprise that many people ask for the pros and cons of roofing over existing shingles.

Let us talk about roofing in simple terms so that you can plan for your roofing project within your budget.

What is Roofing over Existing Shingles?

Roofing over the existing shingles is also known as roof overlay. This simply means that adding a new layer of shingles on the top of the old ones instead of tearing off the original roof completely. It is a quick and cheaper approach than a full replacement.

Sounds simple, right? But it is not the appropriate choice for every household. It is important to first understand how this method works in comparison to the full tear-off before you make any decision.

Pros and Cons of Roofing Over Existing Shingles

Pros

• Cost savings

A roof overlay is usually less expensive than a full replacement You save on labor and disposal costs because there is no need to tear off the old roof. This makes it a cost-effective option for many homeowners.

• Less time consuming process

Since, there is no tear-off the job becomes quick. Your home can be re-roofed in just a couple of days, depending on the size.

• Less mess and noise disturbance 

Without any tearing process, there is less debris and dust and noise to deal with. It is a more convenient way out if you work from home

Cons

• Shorter lifespan

The lifespan of a second layer of shingles is generally shorter as compared to a brand new roof. Heat can get trapped between the two layers, increasing the pace of depreciation of the top layer.

• Hide damage 

Adding another layer of shingles can also cover up the problems beneath, like rot or even a damaged roof deck. This can lead to expensive repairs down the road.

• Heavier load

Roofs are designed only to hold weight. Adding another layer of shingles can put extra stress on the home structure.

• May not be allowed by the building codes

Before considering roofing over the existing shingles, make sure you check with your local building codes. Some areas do not allow more than one or two roofing layers. If you already have the prescribed layers, you won't be able to add more.

• Not the best option for all roofs

Only certain roofs are suitable for an overlay. If your existing roof is uneven or in poor condition, a roof-over might not be the best idea.

Roof Overlay vs Replacement

Let us take a quick look into the difference between roof overlay and roof replacement to make a smart choice for home.

By understanding the major differences you can opt for the best solution of roofing that aligns with our goals.

Is it OK to Put a Second Layer of Shingles on a Roof?

The next big question that arises after selecting a roof layover is, Is it suitable to put a second layer of Shingles on a Roof? Yes, but always make sure to proceed cautiously. Adding another layer of shingles is legal in numerous areas including BC, but local building codes often restrict people to have only two layers. Furthermore, your home should favor the second layer of shingle. This means that the existing roof should be in decent condition. 

Before you make any decision, a roof inspection by a trusted and professional roofing contractor is necessary .

 Roof overlay Cost: What should you expect?

The roof overlay cost depends on the size and condition of your roof. Generally it costs somewhere between 25%-40% less than a full replacement. But remember, what you save now might not be worth it if you need the next replacement soon!

Resale Value and Roof Overlays

A roof overlay can affect your home's resale value. Though it could be a cheap solution in the short run, potential buyers could view it as a warning sign. Roof overlays are normally identified by home inspectors in their reports, and wise buyers may anticipate a discount or a complete roof replacement before they buy.

A complete tear-off offers a fresh, new roof that enhances curb appeal and tells potential buyers the house is in good condition. If you expect to sell your house in the coming months, spending the money on a full replacement will make your house more desirable and worth more.

So, whether you choose to overlay or replace a roof depends on how long you intend to be in the house. If you're going to be selling soon, a complete replacement could be worth it in the way of a higher sale price and an easier sale. 

Don't Forget the Importance of Roof Ventilation

Whether you're thinking about doing a roof overlay or a complete tear-off, roof ventilation is essential. Proper ventilation regulates attic temperature, avoids moisture accumulation, and adds years to your roofing material's lifespan. If you're installing shingles on top of a current roof, you can limit the natural flow of air, which might create mold or premature aging of the new shingles.

A qualified roofing contractor will check your attic and ventilation system before starting the project. They may also suggest adding vents or improve airflow as part of the installation. Ensuring your roof can breathe will protect your home and improve energy efficiency.

Skipping this step might result in real problems regardless of how well your shingles are. So, before adding new shingles always ensure that your ventilation is intact.

Your Roof, Your Decision

Your roof does more than just keep the rain out. It keeps your family, your possessions, and your mind safe. Whether you go with an overlay or a full replacement, it's worth doing it right.Don't know what your roof is missing? Call the professionals at B Cheema Roofing. We provide honest guidance, detailed assessments, and top-notch workmanship you can count on. Let's work together to find the best solution for your house.

Call now at +1 855 454 3454 to arrange a consultation and obtain the roof your house deserves!