What Does A Bad Roof Installation Look Like?

Roof replacement is one challenge property owners face. Though roofs are made to last long with Calgary’s weather, they damage with time, often requiring hiring a roofing contractor for a replacement. 

However, property owners can still find themselves in another challenge by falling into the hands of unprofessional roofers, leading to a bad roofing job. 

When this happens, the roof doesn’t meet expected integrity standards and doesn’t perform well. 

As a property owner, it is important to know how to avoid a bad roofing job by hiring a quality roofer in Calgary; however, it is also important to be able to know when your roofing contractor has done a bad job after the fact.

Although we will cover things to look out for, it’s always a good idea to get a professional roofing inspection when needed.

This piece provides the signs of a bad roofing job and the best way to avoid them:

How to Identify a Bad Roof Installation

A Quick Inspection

One of the easiest means to identify a bad roofing installation is to conduct a quick, visual inspection on the roof. You can conduct this inspection standing on the ground and paying attention to changes to the roof, such as uniformity issues. 

For example, a bad roofing installation can have some parts aging before others. 

Furthermore, check for cracked or missing shingles and exterior walls for stains, signifying leaks in the roof.

This visual inspection also includes checking the roof’s structural elements, such as the decking, underlayment, flashing, and drip edges. Issues with these areas should be curbed immediately, as they are a potential cause of premature leakage. 

However, it is worth mentioning that most signs of a bad roof installation are not present immediately after the installation, but after some time. 

Here are what to look for when conducting a test on your roof to identify a bad roof installation:

Is The Roof Uniform?

After some months after installation, a bad roof install begins to give certain signs, and one of these signs is uniformity issues.

If your roof still maintains its great look on one side but looks old on the other side, your contractor has done a poor job. This is often caused by mismatched shingles, which usually result from the contractor cutting corners to save money. 

Quality work comes from using the same batch of shingles and not mismatching them to save costs.

Are There Sagging Rooflines?

Rooflines should be straight, and a curved roofline is a sign of an error with the installation. When you notice a dip or curve with your roofline, the roofer might have played negligence to the roof decking or framing. It is highly recommended that the roof decking is inspected before a roof replacement, and to not layer shingles on shingles.

Are The Shingles Different In Colours?

One common habit of unprofessional roofers is to run out of shingles during a roofing job. A professional roofer in Calgary, such as Whalley’s Four Seasons Roofing, knows the exact number of shingles needed for an installation and even makes provisions for shortages. On the other hand, a beginner roof might miss on the number of shingles for a project, and when they run out of shingles, they use the ones within their reach. 

This results in mismatched colours in shingles, which is a common sign of a bad roofing installation. You might even have a bit of a bundle leftover, which makes repairs easier.

Are The Materials Uniform?

Similar to, mismatched shingle colours are non-uniform roofing materials. If your roofer runs short of the materials you both agreed on, they might fall back on low-quality materials. This also is a sign of a bad roofing job.

The Roofing Materials Were Not Attached Correctly

Roofing requires different nail types. Using the wrong nail type/size leads to an improper connection between materials. This results in roof damage eventually, and the best way to avoid this is to shun hiring the wrong contractor.

Common Structural Problems of a Bad Roof Installation 

A few structural issues play a part in roof damage. These issues include using the wrong materials, such as nails, resulting in the roof leaking shortly after installation. 

These are common structural problems to check for in a bad roof installation:

Wrong Nailing Techniques

Besides using the right nail type and size, it is also important for roofers to follow the appropriate nailing techniques during an installation. The way the roofer drives the nails into the materials contributes to the roof’s integrity, such that a bad nailing technique can result in roof leakage. 

For example, while an under-driven nail will not penetrate the deck and can be a potential cause of missing shingles, an overdriven nail can cut into the shingle, also increasing the risk of leaks.

Hardware Mistakes

Hardware is a significant part of a roof. Hence, hardware requires equal attention as shingles. Roof hardware includes vents, flashing, nails, decking, and drip edges, which work with the shingles to achieve a healthy, leak-proof roofing system. An error with one section can damage others. 

Hence, you want to ensure your roof hardware is also installed properly. 

Stain on a roof showing water damage

Avoiding Bad Roof Installation 

Bad roofing installation is what you can prevent, and the only feasible way to avoid this is to hire the right hand for the job. Hiring a reputable, quality contractor for your roofing project ensures you are in the right hand. 

Here are a few factors to consider when hiring a quality, professional contractor for your next roofing project:

License and Registration: ensure your roofer has been vetted and certified by the necessary body to undertake jobs relating to your roof type in Calgary.

Experience: experience matters in every professional, and the roofing professional is no exception. Make sure they have the experience in your roof type and if it is residential or commercial.

Insurance: hiring an insured roofing contractor means they are covered should anything go wrong with the project.

Reviews: what your contractor’s past customers say about the company matters. It gives you an idea of what to expect with the contractor working on your roof. 


A bad roofing job can be a nightmare. It hurts to receive a low-quality job after paying for a professional service. However, while you can blame the bad job on your roofer, it is important to take care of your roof and revisit the installation. If you are unsure, getting a second opinion from a reputable roofing company may be required.

If you are looking for a reputable, competitive priced,  professional roofing contractor in Calgary, Whalley’s Four Season Roofing is your go-to roofer. At Whalley’s Four Seasons Roofing, we specialize in commercial and industrial roofing in Calgary, Alberta, and are always available for your roofing project. 

Contact us today for your free roof estimate. 

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