Top 5 Causes of Roof Leaks

he call is made in the first place. What requires expertise is determining the leak’s origin and identifying its cause. As a professional roofing contractor, it is our business to diagnose these types of problems on a daily basis. Below is a list of the most common roofing problems that we encounter in regards to a leaky roof.

1: Broken or Missing Shingles

No matter which material a roofing shingle is made of, it is susceptible to cracking, erosion and other damage such as being blown off in high winds. A shingle’s job is to protect the roof from water damage and rotting. Being so high up on a roof, shingles are often out of range from a home owner’s vision and when damaged or missing, go unnoticed. It doesn’t take very long for a broken shingle to translate into a leak inside the home. Therefore, regular inspections of your roof are important.

2: Damaged or Improperly Installed Flashing

One of the biggest issues that we see in roofing systems is damaged or improperly installed flashing. Flashing is the metal material that is used to line joints, seams and other transition points on a roof providing water protection. Because the material is metal, flashing is highly susceptible to corrosion, rusting and even bending with the natural shifting of a structure. Flashing is only visible in certain places, and can lie beneath the shingle surface. An experienced roofing contractor will know exactly where the flashing lies and will be able to inspect it safely without causing further damage to a roof.

3: Plumbing and Ventilation Leaks

Many home owners have plumbing and ventilation systems ran through the roof of their house. Most roofing contractors advise against it, due to the frequent occurrence of leaks, but we see it all the time on roofing jobs. If you have a leak in your roof and pipes, hoses or other ventilation is in the vicinity, there’s a good chance that this is the culprit. Hire a qualified roofing contractor to perform a professional inspection and diagnose the cause of your leak.

4: Cracked or Corroded Chimneys

In roofing, chimneys are also a common cause of roofing leaks. Whether the chimney is metal, brick or stone masonry, it can be susceptible to cracking, swelling, corrosion and other degradation over time. When we visit a roofing site with a chimney, it is one of the first places we inspect for a leak. These areas also emit heat during the winter season, creating a constant “freeze / thaw” cycles on the roof. This may lead to ice dam issues which in return cause leaks in the winter. This can be corrected in most cases by having a self sealing membrane installed under the shingles in the area.

5: Skylights

Skylights are beautiful and add a generous amount of sunlight to your home, but they can also inadvertently add water and cause leaks inside. A skylight is nothing more than a hole in your roof, covered by glass and secured with caulking and other materials that break down over time. If you have a leak in your roof and have had a skylight installed (whether it was recently or several years ago), this may very well be the cause. Again like a chimney, skylights are a source of heat loss from the home. This may cause ice dam conditions in that area during the winter season. Correct installation with proper materials is vitally important. *Special Note* The life expectancy of a typical skylight is approximately 20 years. If you are considering a roof renovation or replacement, a skylight should be replaced with new at the same time.


Don’t try to fix something with a tube or can of tar. If tar is required to stop a leak on a sloped shingled roof, then you have a serious problem. Tar patching is a band aid solution which will return to haunt you sooner than later.

If you have a leaky roof seek the advice of a professional roofing company. Knights Roofing Ltd is a professional roofing company with many years of experience servicing the Greater Edmonton and Alberta region. Call us at 780-477-1031 to schedule an appointment for a free estimate.