The 10 Most Common Causes of Roof Leaks and How to Identify Them

The truth is, despite your roof being one of the most important parts of your home, most homeowners are unaware of the current condition of their roof. Issues that arise in regards to your roof are often not apparent without a visual inspection, and since your average homeowner doesn’t spend much time on their roof, the first signs they notice of a problem is likely when a roof leaks occur and water starts pouring into their home.

There are many issues that can eventually lead to a roof leak, but if you identify them early on, you can save thousands of dollars by avoiding costly repairs. Today, we’re sharing the 10 most common causes of roof leaks and how you can identify them before they cause additional damage.

Disclaimer: Venturing onto your roof is a risk for serious injury and can also cause damage to your roof. If you choose to self-inspect your roof, please do so under ideal weather conditions, utilize the proper precautions and safety equipment, and NEVER venture onto your roof alone!

Broken or Missing Shingles

The shingles on your roof create a waterproof shield that protects the plywood sheath from the elements. Missing shingles allow water to soak the exposed area of your roof, which can degrade the materials and eventually lead to a roof leak. Even if you are from an area that doesn’t get much rain, changing weather conditions will wear down the weatherproofing and adhesive layers, and make your roof susceptible to dry rot.

Missing shingles are easy to spot, and can sometimes be identified without ever needing to get up on your roof if your roof has a steep enough slope to view from the ground. Some signs of shingles that need to be replaced are:

  • Curling or buckling shingles
  • Shingles that are cracked or broken
  • Excess granules in your gutters
  • Bare spots on your roof which are typically darker in color than the rest of your roof
  • Finding pieces of shingles around the outside of your home


Out of all the potential issues that can cause a roof leak to a residential home, damaged flashing is the most common culprit. Flashing is a thin layer of protective material, such as galvanized steel, copper, or aluminum that is installed around joints, crevices, and vertical surfaces to prevent water from entering your home by creating a smooth surface that directs water downward.

Unlike missing shingles, this is most likely an issue that requires closer inspection. Some of the most common areas to find flashing is around the base of chimneys and vent pipes, valleys, roof ridges, skylights, and dormers. Once you locate the flashing on your roof a few common signs to look for that may require repair are:

  • Rust or corrosion
  • The presence of ice dams
  • Missing pieces
  • Holes or cracks  
  • Mold
  • Staining
  • Damage to the siding or shingles

Chimney Damage

A chimney is a vertical structure designed to create an upward draft that removes warm air, smoke, and gases from inside your home. While most people associate chimney’s with fireplaces, it’s important to note that any fuel-burning appliances will also have a chimney, and since all chimneys operate in a similar fashion, identifying causes for leaks will apply to all the chimneys on your roof.

Chimneys are composed of various components, but rather than breaking down all the complexities of how a chimney functions, we are going to focus on the areas that are most likely to cause a roof leak by explaining where these parts are located and what to look for.

  • Chimney Cap – Located on the uppermost part of your chimney, a chimney cap prevents rain and snow from directly entering the opening of your chimney. If your chimney does not have a protective covering, we recommend acquiring one ASAP.
  • Cement Crown – The chimney crown refers to the sloped cement at the top of your chimney and is designed to keep excess water from reaching and damaging the mortar in the bricks. As cracks appear in the crown, water which enters the cracks and freezes will cause these cracks to expand over time, leading to leaks and possible failures to your chimney system.
  • Brick Mortar – Just as with your chimney crown, cracks in the mortar, which hold the bricks together, allow moisture to enter which will expand over time due to freezing and expanding. Additionally, since brick and mortar are porous materials, excess moisture can lead to mold.
  • Chimney Shoulder – Chimney shoulders are the area of a chimney that transitions from a wide base to a narrower base as it rises. The slope of the chimney shoulder can prevent water from draining properly. When inspecting your chimney shoulder look for moss growth, bricks that are darker in color, or erosion.
  • Flashing – Located at the joint where your chimney meets the roof. Please refer to the flashing section of this blog for tips on identifying issues with flashing.

Your Vent Booting is Cracked

Vents that protrude from your roof exist to allow gases from the interior of your home such as your kitchen and bathroom to escape outside. To prevent leaks, vents are installed with vent boots that create a waterproof seal around the base of the vent. Vent boots, especially cheap ones, will deteriorate far more quickly than other parts of your roof and can lead to leaks even if your roof is still in perfect condition. If you are noticing peeling paint or watermarks in your kitchen or bathroom or damage to the shingles around your vents, it’s a good idea to inspect your vents for:  

  • Cracks in the rubber seal or damage to the vent boot
  • Rust or cracks to the collars of the vent pipe
  • Broken seams in the metal base of the vent
  • Loose nails holding the base in place

Condensation in the Attic

Moisture in your home is not always caused by a leaky roof. In some cases, it can actually be caused from within your home. Attic condensation is most common during the winter season when the temperature outside is significantly lower than the temperature inside your home. As warm water vapors rise and enter a cold attic, these vapors are converted into a solid-state which become large water droplets aka condensation that forms on the wood in your attic.

Condensation can cause wood to rot and mold to spread throughout your home, both of which can be VERY costly to repair. To prevent condensation, it’s a good idea to check your attic’s insulation as well as your ventilation system. 

clogged gutters

Clogged Gutters

The main function of gutters is to carry water away from your home, but when your gutters are clogged, constant moisture present from the stagnant water that remains can lead to rotting and eventually a roof leak. If you live in an area with large amounts of rainfall, roof leaks can appear much faster as water accumulates, settles against your roof, and find its way underneath the shingles which causes damage to the underlying materials. Excessive damage to the underlying materials can be cause for a full roof replacement if not addressed, so this is not something you will want to neglect.

If you notice:

  • Staining on your siding
  • Sections of your gutters sagging
  • Water overflowing during rain
  • Insects, birds, and other pests   

It’s time to clean your gutters.

Lack of Maintenance

The best time to fix any issues with your roof is before a leak occurs. As well as being aware of the most common causes of roof leaks and what to look for, some simple maintenance can prolong the life of your roof and allow you to catch any issues before they develop into something more serious. While it is always recommended to hire a professional who knows the proper safety procedures, there are a few things you can do yourself if you feel comfortable doing so, that can help prevent damage before it occurs.

  • Remove tree branches that are too close to your roof
  • Clean your roof of any debris after a storm
  • Check for discoloration or the presence of moss, algae, or fungus
  • Avoid DIY fixes. (A minor mistake such as a misplaced nail can lead to severe damage if left unattended.) 

Poor Installation

Roofing is a highly specialized profession that leaves little room for error in regards to installation. Installers who lack training or pop-up roofing companies that are especially prevalent after storms will perform subpar work that is often not apparent until the bill is paid and the company is long gone. Rather than waiting for a roof leak to occur, there are a few signs you can look for after repairs or installation to verify the quality of the work such as:

  • Poor alignment of materials
  • Bumps or ripples in the surface of your roof
  • Missing or damaged shingles
  • Using too many or too few nails based on the manufacturer’s guidelines
  • Lack of drip edges
  • Failure to clean up any leftover debris or garbage
  • Damage to the exterior of your home

These are some of the more obvious signs that most homeowners should be able to notice, and if present, should be addressed immediately. However, the best way to prevent improper installation is to do your research ahead of time to ensure you are hiring a reputable company. Always make sure to ask for reliable referrals.  

Valleys That Aren’t Sealed Properly

The valley of your roof refers to any area where two planes meet to create a low point. Since valleys are sloped, and often fairly wide, if the seam is not properly sealed, it is easy for water to seep through. The break in the seal is often caused by improper installation, damage from foot traffic, or erosion from the elements. The most common ways to identify a valley that is improperly sealed is to look for wet spots along the seams or debris pile up.

Ice Dam Buildup

Ice dams are a build-up of ice that forms near the edge of your roof. These ridges of ice prevent the passage of water, and can allow moisture to enter your home as water pools behind the ice dam. Unlike many other causes of roof leaks which are the result of improper installation or erosion, ice dams are caused by a combination of snowfall, prolonged temperatures below freezing, and nonuniform surface temperatures on your roof. Various factors can cause surface temperatures to be warmer at higher points and colder near the edges, which causes snow to melt and refreeze as it reaches the edge of your roof.

Since ice dams typically form near the edge of your roof they can often be seen from the ground. (Venturing onto your roof during snowy or icy conditions is NOT recommended).  A couple of things to look for are ensuring any icicles are confined to the gutters, and there is no water forming behind them, as well as any stains in your attic or along your ceiling.

While removing ice may seem simple enough, keep in mind that shingles can be pulled off along with the ice, and any chemicals you use such calcium chloride can damage plants and shrubbery as the chemically saturated water drips from the roof. Removing the ice is a temporary solution, as you will need to address what is causing the temperature imbalance for a permanent solution.

Save Thousands By Preventing Roof Leaks

Now that you know the most common causes of roof leaks and how to identify them, you can use this information to address issues early on and save yourself hundreds or even thousands of dollars in repairs from preventable damage. If you have any additional questions about your roof, have identified potential causes for concern, or require a professional to come inspect your roof, make sure to reach out or fill our form for a free inspection. Keep your home protected with Brahma Roofing and Construction. 

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