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  • Writer's pictureJohn@LiteHouse

Consequences of Upper Roof Downspouts Discharging onto Lower Roofs

Proper water management is a fundamental aspect of maintaining the integrity and longevity of any building. One common issue that can have significant consequences is when upper roof downspouts discharge water directly onto lower roofs. This practice may seem convenient and, to be honest, is a very common installation method used by a lot of home builders. However, it can lead to a range of problems, including roof damage, structural issues, and water infiltration. In this blog post, we will explore the reasons why upper roof downspouts should never discharge onto lower roofs and discuss alternative solutions to ensure effective water drainage.

The Problem with Upper Roof Downspouts Discharging onto Lower Roofs:

1. Increased Roof Stress:

When water from upper roof downspouts is directed onto lower roofs, it creates a concentrated flow of water in a specific area. This concentrated flow can overload the lower roof, leading to increased stress on the roofing material, joints, and fasteners. Over time, this added stress can weaken the lower roof's structure, resulting in leaks, deterioration, and premature failure.

2. Roof Damage and Premature Aging:

Continuous water flow from upper roof downspouts can cause excessive moisture accumulation on the lower roof. This prolonged exposure to moisture can lead to the growth of mold, mildew, and algae, which can degrade the roofing material. Additionally, the force of the water hitting the lower roof can cause surface erosion, stripping away protective layers and accelerating the aging process.

3. Water Infiltration and Leaks:

When water from upper roof downspouts is discharged onto lower roofs, it increases the likelihood of water infiltration. The force and volume of water can overwhelm the lower roof's drainage system, leading to pooling, ponding, and eventually, leaks. Water infiltration not only damages the roof structure but also poses a risk to the interior of the building, potentially causing water stains, rot, and compromised insulation.

Alternative Solutions for Effective Water Drainage:

1. Redirect Downspouts Away from Lower Roofs:

The simplest and most effective solution is to redirect the downspouts from upper roofs to discharge water away, or past, lower roofs. Install downspout extensions or piping to direct the water to a lower gutter, or a downspout extension that directs water to the ground away from the lower roof.

2. Install Gutter Guards and Filters:

To prevent debris from entering the gutter system and clogging downspouts, install gutter guards and filters. These devices allow water to flow freely while keeping leaves, twigs, and other debris out of the gutter system. Clear gutters and downspouts regularly to maintain optimal water flow.

3. Ensure proper flashing is installed:

Proper step flashing on side walls and kickout flashing at eaves will help in directing the rain water and prevent damage to your home.


Proper water management is essential for maintaining the longevity and structural integrity of any building. Upper roof downspouts should never discharge water directly onto lower roofs due to the potential for roof damage, structural issues, and water infiltration. By redirecting downspouts away from lower roofs, you can effectively manage water drainage while protecting your building's roof and structure. Remember, regular maintenance and inspections are crucial to ensure the continued effectiveness of these solutions and prevent costly water-related issues in the future.

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