Deteriorated Roof Gutters and Components

We recently completed a beautiful new roof replacement job at a historic row home.   While working on the upper roof, we also happened to notice that the lower gutter and downspout needed repair.   We’ll show more details of the upper roof in a forthcoming post, but this particular gutter and downspout was attached to a small gable roof specific and limited to the front entry foyer which was positioned in front of the remainder of the front facade jutting outward in an extension, part of the original construction.

The original downspout was a blue patina copper 4″ downspout with a half round gutter.   The particular downspout and gutter were connected to the gable roof above the front entry of the building.  The particular downspout actually was a shared element because while it was connected at the gutter to the roof of our clients’ building, it also received the majority of contributing rainwater from the neighbor’s front mansard roof.    These two roofs both shared the same downspout and drain. It’s generally better for all components of individual buildings to be built completely separate and individually distinct, but in this case for architectural simplicity, both buildings shared the same elements of rain diversion, downstream of each building’s respective individual roof.  At times, in rare cases, it may be difficult to coordinate costs and / or expenses between neighbors but in this particular case both clients were extremely friendly and amenable and worked together in the spirit of collective building maintenance and management.


In this particular case, the downspout had split at the vertical seam, likely from a restricted and slow drain in the past that led to water freezing and expanding during freeze-thaw type conditions or fluctuating temperatures around 32゚F.   It might seem counterintuitive, but temperatures that fluctuate around 32゚F, just a little bit above and just a little bit of below freezing, in cycles, generally can cause more severe damage to building materials then even the deeper freezes.


The split occurred near the mounting location and allowed water to seep out of the downspout one to the surface of the brick wall. The brick wall is a historic masonry wall and therefore, over time this brick and mortar is comparatively more porous than modern masonry.   The residual leakage allowed water to seep through the brick mortar joints and into the building.


Also, over time the downspout outlet oxidized where soldered to the half round gutter.   It’s likely that deterioration happened at an accelerated rate due to material compatibility conflicts. Alloys used in soldering often include metals that might work as a dialectic with copper. Dialectics or anode-cathode type relationships between dissimilar metals can result in accelerated oxidation.


Rain gutters, downspouts, rain leaders, and even underground drain systems are all part of the greater water diversion systems. Roofs are built to shed water from the top of the building away from the building, carrying the water continuously without allowing the water to enter the building itself. Gutters and downspouts are separate from roof systems yet these separate systems are in fact connected and interrelated. Even when not integral in the roof system themselves, these components are often important related system accessories.

Smart proactive replacement, construction, upkeep and maintenance of low slope roof systems requires an enthusiastic interest and understanding of waterproofing principles and building science.   Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building.

We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the roof and related systems of your building in Washington DC, fill out the webform below and drop us a line.  We will be in touch if we can help.

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