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12 Reasons Why A Roof Leaks In Heavy Rain (& How To Fix It)

Posted on : June 25, 2024

12 Reasons Why A Roof Leaks In Heavy Rain (& How To Fix It)

Discovering a leak in your roof when it's pouring outside can be stressful for any homeowner. Water coming into your home is one of the most common roof problems that can result in stains, structural damage, and ruin the visual appeal of your home, which is why it’s important to fix roof leaks fast.

In this blog post, we'll talk about why roofs often leak when it's raining and give you practical ways to fix these problems.

What Are Common Causes of Roof Leaks In Heavy Rain?

As a homeowner, you might wonder, “Why does my roof leak in heavy rain?” To help you out, we have listed some reasons why a roof leaks in heavy rain: 

#1. Improper Roof Flashing

Improper Roof Flashing

Roof flashing, installed around chimneys, vents, and skylights, prevents water from seeping in. Poor installation, cracks, or rust can create a pathway for water to enter the home, leading to roof leaks in heavy rain, damage, and costly repairs.


Ensure flashing around chimneys, vents, and skylights is correctly installed. Regularly inspect the flashing to promptly detect and replace any cracks, rust, or damage.

#2. Clogged Gutters and Downspouts

Clogged Gutters and Downspouts

Gutters and downspouts carry water away from the roof, siding, and foundation of your home. When clogged with debris, they cannot effectively perform this function, causing water to back up under the shingles and leak into the home. Heavy rain increases the pressure, raising the likelihood of leaks.


Regularly clean gutters and downspouts to maintain proper water flow. Install gutter guards to prevent debris buildup and ensure downspouts extend at least 3 feet away from the foundation.

#3. Damaged Roof Underlayment

Damaged Roof Underlayment

The underlayment beneath the shingles provides an extra barrier against water. If the material becomes damaged or worn, it may no longer protect the roof structure from leaks during heavy rain, leading to significant water damage and repairs.


Inspect and replace damaged underlayment. Properly seal and install these materials to effectively prevent water from seeping through.

#4. Cracked or Broken Skylights

Skylights can leak during heavy rain if the seals or flashing around them deteriorate. Cracks or gaps in the skylight itself also allow water to penetrate the roof, causing significant water damage if left unrepaired.


Routinely inspect skylights for cracks or damage. Repair or replace damaged skylights and ensure proper installation and sealing around them.

#5. Improperly Installed Roof Valleys (Debris in Roof Valleys)

Improperly Installed Roof Valleys

Roof valleys, where two roof planes meet, are vulnerable to leaks if not properly installed or clogged with debris. Water can pool and weaken the roofing material, which allows it to seep into the home during heavy rain


Maintain proper installation and cleanliness of roof valleys to prevent water pooling and potential leaks.

#6. Tree Branches and Debris

Overhanging tree branches and accumulated roof debris impede water drainage, leading to leaks. Branches can damage shingles, while debris holds moisture on the roof. Heavy rain and storms can cause branches to break off, causing further damage.


Trim overhanging tree branches to protect shingles and keep the roof clear of debris. 

#7. Pipe Boot Failure

Rubber or neoprene boots that seal the base of plumbing pipes can deteriorate over time, allowing water to seep in around the openings. These boots need to be replaced periodically to prevent leaks.


Regularly check and replace worn out rubber or neoprene boots around plumbing pipes. Ensure correct installation and sealing to prevent water infiltration.

#8. Damaged or Missing Shingles

Damaged or Missing Shingles

Severe weather can damage roof shingles, especially on older or poorly maintained roofs. Brittle shingles crack, allowing water infiltration. Improperly secured roofing nails also create openings for water, potentially lifting shingles and compromising roof integrity.


Inspect your roof regularly and replace damaged shingles promptly to prevent water infiltration. Professionals or skilled homeowners can do this upkeep. Ensuring proper installation and maintaining the roof's condition prolongs its lifespan, shielding your home from leaks.

#9. Age

As roofs age, the materials become worn and less effective at preventing water intrusion. Older roofs, with brittle shingles and deteriorated underlayment, are more susceptible to leaks during heavy rain.


Perform regular inspections and maintenance on older roofs to detect and address potential issues before they lead to leaks. Consider replacing aging roofs to ensure continued protection against water intrusion.

#10. Incorrect Roof Slope

Roofs with an improper slope or pitch do not effectively shed water, leading to pooling and potential leaks. Flat roof leaks in heavy rain caused by an incorrect slope can create an environment conducive to mold and mildew growth.


Maintain proper installation and alignment of roof slopes to ensure effective water shedding and prevent water from pooling.

#11. Chimney Issues

Chimneys with cracked mortar, damaged flashing, or deteriorating caps can allow water to enter the home during heavy rain. Addressing chimney issues is crucial to prevent leaks and ensure roof integrity.


Regularly clean and inspect chimneys to prevent creosote buildup. Additionally, install or replace chimney caps and chase covers to safeguard against water, animals, and debris, ensuring they are properly sealed and installed.

#12. Condensation

Condensation in a metal roofing system can cause significant leaks. When warm, moist air in a poorly ventilated attic contacts the cool metal roof, it leads to moisture buildup. Condensation can cause the roofing materials to deteriorate, rust, and rot. This creates gaps that let water in, especially during heavy rain. If not addressed, the resulting leaks can damage the attic, ceiling, and interior of the home.


To prevent condensation-related roof leaks, ensure proper attic ventilation by installing intake and exhaust vents. A vapor barrier can also help regulate moisture levels and reduce heat gain. Regularly inspect and maintain roofing materials, sealing cracks and gaps to prevent deterioration and leaks. Additionally, properly seal and insulate pipes to prevent water intrusion.

Temporary Fixes for Emergency Roof Leak Situations 

While temporary fixes should not be considered long-term solutions, they can help reduce damage until permanent repairs are possible.

1. Applying Roof Sealant or Caulk

Applying roof sealant or caulk can temporarily prevent water from entering small gaps or cracks. Clean the area before applying the product and follow the manufacturer's instructions. Apply the sealant with a putty knife or caulking gun, pressing it firmly into the crack, and allow it to dry following to the package instructions. 

2. Installing Tarps or Plastic Sheets

Cover the affected area with a tarp or heavy-duty plastic sheets for larger leaks or extensive damage. Secure it tightly to prevent wind or rain from dislodging it. Use roofing nails or sandbags on edges and corners, and consider using rope or bungee cords for extra security.

Remember, temporary fixes are quick but not lasting solutions. Replace them promptly with permanent repairs to prevent further damage and maintain your roof's long-term integrity. Avoid relying on tarps or plastic sheets for extended periods, as they may degrade over time.

Professional Roof Repair Services for Pittsburgh Homeowners

Roof leaks during heavy rain can be frustrating and costly for homeowners. Understanding common causes, as mentioned above, can help you take steps to address these issues. While temporary fixes provide short-term relief, permanent solutions like professional repairs or a full roof replacement are necessary for long-term protection.

For reliable storm damage repair services, consider McClellands Contracting and Roofing. With expertise in identifying and fixing roof problems, we ensure your home stays clean and safe. Don’t wait until it’s too late; contact us at (412) 353-5660 for a thorough inspection and quality repair or replacement services. 

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