A Leak At A Rooftop Chimney

Learn how to find a leak at a rooftop chimney

Today we’re working on repairing a rooftop leak that is entering a building near a skylight.  However, the particular leak happens to be actually coming from an adjacent chimney.

A picture of a chimney, the suspected primary cause of the leak follows below.

leak at a rooftop chimney

Inconsistent Roof Repair Can Cause Leakage

Flat roof replacement is simpler than repair work, in many ways.  Complete roof replacement basically rules out all variables and unknowns by starting back at square one, you get the opportunity to fix all issues and build it right, from the start, anew.  Repairs save a lot of money, yet are more complicated though because identifying the exact location and entry point of a water leak isn’t always possible from the outset.   Since X-ray vision isn’t a real thing (x-ray technology is real but not a pragmatically feasible option in flat roofing repair) and since the location of the leak entry point is often covered by multiple layers of materials, we had to do a lot of pragmatic / programmatic searching.  The process can often be circurcuitive, redundant, and even inconclusive at times, and the cost of searching or testing is expensive, but still much less expensive than roof replacement.

The chimney and skylight are in close proximity to one another, so it made sense to repair both areas at visible areas of concern, just to make sure the leak doesn’t continue if it were to happen to be a multi entry point leak.   The particular building owner had other contractors come and search for this leak in the past and they did minimal ineffective repairs to the chimney but really focused on the skylight and the repairs to the skylight were also ineffective or defective.   We redid those repairs to the skylight but really concentrated on the chimney as well because the chimney was in such poor condition it was nonsensical to us that the other roofer wouldn’t focus in on this glaring detail. 

space in new mortar joints leakage

How Not To Repair or Restore A Chimney

The chimney, before our work began actually looked relatively recently restored;  However, the work that have been done to fix the chimney was not real restoration or repair, it was just a smear on type application of inappropriate non-matching or non-compatible cement.  Some professional tuckpointing specialist refer to this type of fake work as scam-pointing.

In the picture below, you can see that the previous contractor had used both a both a modern mortar which is incorrect yet also not applied it properly.

improper mortar repair

Without force or pressure of any kind, our tape measure slides easily between the brick joints all the way into the flue on the inside of the chimney. Altogether this is a distance of almost five inches, it’s alarming and very surprising that other contractors hadn’t picked up on this before we were called to make repairs to the roof.

roof repair leakage

Bad Restoration Leads To Deteriorated Mortar

The picture below shows a closer view of the deteriorated mortar at this chimney. Although we are roofing contractors, we recommend that any building owner, in Washington, DC or any historic area only works with a roofer who is competent and skilled in both roofing and masonry because almost every rooftop has old chimneys that often need upkeep, maintenance, and repair. More than anything else, it’s important that the roofing contractor also understands the principles behind construction of historic masonry brick and mortar.

deteriorated mortar

Maintaining A Modern Rooftop Chimney The Right Way

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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