Signs of A Bad Roofing Job

March 15, 2023 kellymacdonald


Not all roofing jobs are created equal. Time after time we come upon situations where buildings with brand or relatively new roofs are experiencing leaks. How could this be possible months or a few short years after the roof was replaced?

The answer is likely poor installation.

In fact, water infiltration from improper installation is one of the leading sources of leaks we encounter. When completing a roof installation, replacement or repair, multiple factors must be considered to ensure the new system is being completed correctly and lasting as long as possible. The primary function of the roof is to act as a waterproofing system, ensuring water and other outside forces are being kept out of the building’s interior.


What Your Contractor Must Do to Avoid a Bad Roofing Job

First and foremost, following the material manufacturer’s guidelines are imperative. Regardless of what type of material or membrane system is being installed or who the manufacturer is, all products come with a plethora of information that, when paired with technical training, ensure the job will be completed to standards.

The primary documentation available from the manufacturer includes safety data sheets, technical data sheets and installation guidelines. While safety data sheets may not be relevant to the overall quality of your roofing project, following these guidelines is required for the overall health and safety of the contractors completing the work as well as the building’s inhabitants. These guides outline information like the safe storage and handling of the products, personal protective equipment that may be required during their use, first aid measures in case of incident, along with a wealth of other information, as required by WHMIS.

Technical data sheets also feature information about the storage and handling of the products, though related to maintaining the integrity of the materials and ensuring they will function as intended. Other important information found within technical data sheets that are vital for a roofing project include substrate requirements, surface preparation, minimum and maximum application temperatures, product compatibility and more. If these important requirements are overlooked, it has potential to compromise the quality and overall lifespan of the system.

All manufacturers also provide detailed information on installation methods. Whether the information is delivered through videos, manuals or in-person product training sessions, there are numerous resources widely available for contractors. When completing a roofing project, these factors must all be considered and followed to ensure quality control and to maximize the serviceable lifespan of the roofing system. Ignoring or cutting corners on guidelines provided by the manufacturer will not only impact the overall roof system, but also poses the risk of voiding the manufacturer’s warranty.


What Are the Most Common Bad Roofing Jobs We See?

Modified Bitumen Membrane Installation

Easily the most frequent issue we encounter, is the installation of a 2-ply SBS modified bitumen membrane. Modified bitumen membrane has become one of the leading waterproofing systems for low-slope roofs, often replacing the once popular built-up roofing system. Its flexibility and durability can make it a great, long-lasting roof system – when installed correctly.

Installation methods for a modified bitumen membrane can vary, with torch-on and flameless products available. Regardless of the specific type of modified bitumen membrane being installed, guidelines and best practices must be followed to ensure the system is installed correctly and will keep water out of the building.

Often, the issues we see with installation include stripping membrane not fully extended over walls and other upturns, leaving an opening where water may enter. Membrane seams that are lifting or splitting open shortly after installation are also a common occurrence and can be traced back to poor installation methods.

Shingle Roof Installation

Not only can detailed installation information be found online or provided direct from the manufacturer, but each bundle of shingles comes with basic installation guidelines displayed right on the packaging.

One of the most common errors we observe that can lead to dire interior leak issues, is the placement of roofing nails. Per the installation guidelines, roofing nails are to be installed underneath the shingle tabs and should not be visible. Too often, we encounter instances where nail heads are visible throughout the roof surfaces. Should these nails begin to lift or rust it leaves the roof susceptible to water infiltration. These deficiencies can be difficult to spot without accessing the roof personally or having a wide range of detailed job photos. Often, the shingles themselves will appear intact and well installed, when viewing the roof from ground level.

Improperly placed nails can also leave the shingles vulnerable to wind damages, also leading to potential for leak occurrences and requiring costs for repair. In Southern Ontario, we have experienced a high volume of powerful windstorms over the last several years, so ensuring a home’s shingles are installed to withstand all elements is greatly important.

Improperly Installed Roof Flashing

Roof flashing installed at the penetrations throughout the roof surfaces, at areas like the vents or plumbing stacks, can commonly have two errors that may lead to water infiltration. The first occurrence is when this flashing is not adequately roofed-in with a compatible waterproofing membrane.

On a variety of roof systems, we have seen situations where the roof flashing is sitting atop the membrane, rather than having the base of the flashing installed beneath the membrane. This has led to numerous leak issues since the flashing is not sealed and leaves space for water to enter.

Improperly installed roof flashing can be harder to detect on inverted roof systems, where the membrane is covered by insulation, filter cloth and gravel ballast or paving stones. When having repairs or new membrane installations completed, it is important to have photo documentation of the work at the very least, to ensure potential deficiencies are detected early.

Improperly Sized Roof Flashing

The second common occurrence we see with roof flashing is when size is not right. Manufacturer’s offer a wide range of flashing options and sizes, and custom options are available when needed. If the size of the flashing is too big, voids will be present at the penetrations and can lead to water infiltration.

Often when we encounter flashing that is not the right size the contractor who completed the original installation has applied caulking or another sealant to minimize water infiltration. However, caulking, and other sealants will not last forever, and their application is not preferred to hardwarethat fits properly.

Concrete Coatings

Surface preparation is always a vitally important step when completing any installation or application of a waterproofing system. This is especially true when applying an epoxy or polyurethane coating to concrete surfaces.

When steps outlined in the technical data sheets and installation guidelines are rushed or skipped altogether, you may see chipping, flaking, or cracking occurring in the coating shortly after it’s application. Not only can these defects be unsightly, but they also compromise the waterproofing system, and may lead to leak issues.

Use of Incompatible Materials

Just because products are made for a roof does not mean they can all go together. Regularly, we come across repair jobs for leaks or other damages where incompatible materials are used. Occasionally, we have also seen entirely different membrane systems being used for patch repairs. If the chemical compounds of the various roofing materials being used are not compatible, issues with adhesion and the overall durability of the repair can be affected. Often this results in patches lifting and allowing water to infiltrate the damaged area once again.

Technical data sheets will offer information about compatible materials that can be used for a specific roofing product. To ensure products being used are compatible with one another, don’t be hesitant to ask your contractor to provide details on the materials being utilized for a roofing project. If the contractor is not willing to provide these details or claims they are unavailable, it could signal a major red flag.

If you are experiencing a leak following a new roof installation or project and need a second opinion, we are always on-hand to help. Contact us at 905-230-2969 or to schedule a service crew to investigate.

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