A Leak At A Rooftop Chimney – Part II

Part 2 of A Leak At A Rooftop Chimney

Last week, we took a look at a rooftop leak that was actually emanating from the location where the roof membrane terminated or bonded to the chimney. The connection point between the rooftop and the chimney is usually terminated in a counterflashing or termination bar.

A link to that article from last week follows below for reference.


The previous segment of this topic actually showed the chimney after we had started picking apart the existing mortgage joints. The picture below, by comparison, shows the chimney right at the start of a work before we had started removing the scan pointing from the surface of the deteriorated mortar joints. 

Here in this picture, you can see the counter flashing at the top of the roof termination where the roof meets the chimney and you can see the counterflashing, on the neighboring side of the chimney. The neighboring side of the chimney. The neighboring side of the chimney has a white aluminum counter flashing at this side of the roof system termination is a galvanized steel, silver or zinc color.   Chapter 9 of the building code, for Washington DC has specific requirements for roof installation and although the code book itself doesn’t contain nearly the amount of details required by the code by extension through referencing manufacturer standards, the code clearly requires counterflashing. 

counterflashing leak at a rootop chimney

One of the many interesting things about this chimney and the context of where the chimney meets the adjacent roof system is that the chimney, while it needs to be maintained to prevent water from entering the building, is not even in use. The chimney has been abandoned or removed from use in the building years ago.  We often see situations like this, especially where a real estate developer does a dirty-flip and pushes as much of the building upkeep, maintenance, or defect type responsibilities or requirements under the rug so nobody notices and they get to sell the building for a higher cost than it might actually be worth or at least avoid doing the majority of their part of the upkeep or maintenance to reduce spending.

The next three pictures below show the deteriorated mortar joints with this fake scam pointing or cover up type brick pointing on top of but barely covering the existing deteriorated mortar.

deteriorated mortar joints 1

deteriorated mortar joints 2

deteriorated mortar joints 3

Maintaining A Rooftop Chimney for Leaks

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, contact us or fill out the webform below and drop us a line.  We will be in touch if we can help.

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