Commercial, Mixed-Use and Strata Roof Maintenance in Vancouver, B.C.

9 Common Issues Causing Leaks on A Sloped Shingle Roof.

9 Common Issues Causing Leaks on A Sloped Shingle Roof.

Sloped shingled roofs are tough to maintain and even tougher is to locate a leak in them. As a roofer myself, I usually suggest my clients avoid the causes of leaks if they have this type of roofing system.

Leaks are caused by sloped shingled roofs due to wildlife, broken shingles, cracked chimney, unsealed vents, clogged gutters, improper installations and many more reasons.

In this article, I have highlighted 9 common issues causing leaks on a Sloped Shingle Roof. Along with the easiest way to spot the defect and a solution to it.

1. Old Roofs.

Age gets the best of anyone and anything and our sloped shingle roof is not an exception. Old roofs that have far surpassed their expected life span are prone to leaks. The passing seasons and the changing temperatures take a toll on the materials of the roof and weaken them.

How to spot this defect?

Compromised and old roofs are not hard to spot. Even a well-maintained roof past the age of 20-25 years will start showing signs of ageing and eventually cause problems.


Roof replacement is the best solution for aged roofs.

2. Wildlife.

No matter where you live or the type of roofing system you have. Animals like mice, rats, raccoons, or possums find a way to secure a home in your roof’s shingles. Furthermore, if you live in areas nearing the woods. Other animals and even birds will find a way to burrow a hole in your roof and live there.

How to spot this problem?

Wildlife infestations can be spotted with the naked eye. Take a closer look at your rooftop.


Don’t let debris collect on your roof. Seal any hollow spaces between shingles and inspect your rooftop. Timely roof maintenance is the key.  

3. Excessive Flora.

Unless you have a green roofing system, trees and plants are bad news for your roof. Trees shed leaves which accumulate over the roof and trap water and other things on the roof. Plus, storms and bad weather result in broken branches and sometimes even fallen trees on the roof. All this causes considerable damage to the roof.

How to spot the issue?

It’s best to check your roof after a storm or an excessively rainy day. Besides, rid your roofs of accumulated debris periodically. As most of this debris is dried and decomposing leaves.


To save your roof from leaks caused by broken branches, fallen trees or collected tree waste, contact a roofing contractor as this is a job of a professional. Venturing on your roof without any safety gear could be dangerous. Especially after a storm.

4. Broken Shingles.

The top reason for leaks on a sloped shingle roof is often broken shingles. Shingles are the outermost layer of your roofing system. They are most exposed to the elements hence a cracked or broken shingle is common. However, if you ignore broken shingles over time the chances of water seeping in and causing leaks are high.

How to spot this problem?

Being the topmost layer of the roof, you can easily spot a missing or broken shingle. Mostly, you can find a fallen shingle in your yard or you can identify the different coloured patches on your roof. Either way, a displaced, broken or missing shingle is easy to spot.


If you have the necessary equipment and experience, by all means, replace the missing shingle on your own. However, if you lack either, you will damage your roof rather than repair it. It’s best to contact a roofing professional to fix the problem in that case.

5. A Cracked Chimney.

Chimneys seem to be the strongest part of a building, as they stand strong even after the house is in complete ruins. Check out any 100+-year-old house and the first thing you will spot is a chimney in good shape.

However, we need to understand that these seemingly indestructible chimneys are made of nothing but bricks and mortar that firmly bind the bricks together. This mortar can erode and weather away with passing seasons. This weakened binding creates cracks that eventually lead to leaks.

How to spot this defect?

Look for signs of wear and tear at the top of the chimney or the mud cap. Next look at the joints where the chimney meets the roof. Generally, you can pot the deteriorated mortar in this region. Sometimes even the nearby shingles are loose or damaged.  


Patching the mortar where required is the quick fix. However, it’s best to hire a roofing professional to complete the task, as the materials required for fixing a chimney are different from the ones for regular roofing fixes.

6. Unsealed Valleys.

The beauty of sloped shingled roofs lies in their elegant slopes, and with slopes we have valleys. A Valley is a place where two slopes of a sloped shingle roof come together. As this area bridges two slopes, a lot of water flows over it.

Sometimes accumulated ice or water can cause leaks. Many-a-times valleys are not properly sealed and which causes leakage. Valley seals can break if they are stepped on while working on the roof too.  

How to spot this issue?

Look for wet spots that run along the seams of your roofs. The collected ice and constantly flowing water erodes the seals of the valleys, which leads to cracks and leaks.


The valleys need to be resealed. This has to be done by a roofing professional. As the process of laying a new leak barrier along the valley and shingling overtop is a complex process.

7. Improper or Incomplete Installations.

Roof installation/ replacement is a long and complicated process, tedious even. Therefore, occasionally we have customers complaining about improper installations. Whether it’s incorrectly installed skylights or vents, water can seep through the cracks or unsealed areas and cause leakage.

How to spot this defect?

Observe the part of the roof which you suspect was inaccurately installed. Clean the debris around for a closer look. If you can’t spot anything it’s best to call a roofing contractor.


Generally, leaks caused by wrongly installed skylights, vents, etc. can be easily sealed. However, it may not be a safe practice to do it yourself without any protection or experience. These repairs are cheap and quick, so it’s better to get the leaks repaired by a roofing professional.

8. Clogged Gutters.

If you have a sloped shingled roof, you may have encountered clogged gutters at least once. Bad weather, the buildup of debris, dried leaves and sometimes even animal infiltration chokes the gutters. Once the gutter is blocked water is stagnant on your rooftop without an outlet, which eventually leads to leaks. Plus, if water is accumulated on your roof for too long its sheer weight of it can cause structural damage.

How to spot this issue?

It’s pretty simple! If you see leaves or other dirt sticking out of your gutter, chances are it’s blocked or about to be clogged. Furthermore, if water is not trickling down the downspout, you need to double-check your gutters.


You can unclog your gutter yourself if it is accessible, otherwise, it’s best to contact a roofing contractor to inspect and clean your gutter and fix the leak.

9. Poor Venting.

Poor venting can cause some unnecessary trouble. The leaks caused by faulty vents are of two types; Excess condensation in your attic or Leaks in the vent itself.

If you have a limited number of vents, it may cause condensation in your attic. Growth of moulds, damp air, musty odour, etc. are the tale tells of water seeping inside. As your attic is a place where roof temperature collides with outside temperature, leakage caused by condensation is normal here.

On the other hand, unsealed or improperly installed vents eventually lead to leaks around the gaskets around the vent pipes.

How to spot this problem?

Leaks in the attic are easy to identify as the air in the attic itself will be chilled and damp due to the water intrusion. However, you need a professional roofer to take a look at your vents.


It’s best to contact your regular roofing contractor to address both these problems


I hope this article has offered you the necessary knowledge you need to trace leaks in your sloped shingled roof. Yet, if you need a professional to take a look, ring us up!

Leak Stop is a one-stop destination to meet your roofing-related requirements. We offer roof repair, replacement, maintenance and inspection services all over GVRD (Greater Vancouver Regional District).

We offer a free inspection to first-time clients. Connect with us TODAY at 1 866 777 0084 for immediate assistance!

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