Rear Terminations at Garage Roofs: Key Considerations and Solutions
Recently, we took several pictures showing the damage at rear roof terminations at garages, all within a particular block. Often, especially here in Washington dc, and interesting phenomenon happens where we start working on one house to make one type of repair and then neighbors ask us to make the exact same type of repair at their house as well, and this process repeats again and again. Often, homeowners and building owners are just happy to find a good contractor who cares about quality and likes serving their customers because although contractors aren’t rare, good contractors are less common.
In the picture below, you can see the first of many examples of garage roofs with particular damage at the rear termination. A low slope or flat roof generally will grade to one side, if the overall configuration of the roof for building is relatively simple.
In larger commercial buildings, the average roof size and configuration would be much larger and more complicated. And roofs like that, the building will often have large spans, larger than which a roof can easily grade across in one direction. Instead of a single rear termination type drain, a roof in that context will often have many internal drains as well.
Here though, in these small and simple garages, they instead have a rear termination which is the intended low point of the roof. The word *intended* is specifically selected because although the original design and layout intended for the rear most point of the roof to be the lowest point in the roof which would allow water to drain freely from that point, these roofs have often and in many cases been modified and rebuilt over the years and in many cases the rear termination no longer works to be the low point in the roof. That type of problem is normally caused by accident or by deterioration or damage. For example, in many cases, when other roofers or DIY enthusiasts are trying to save money they may install a new roof without modifying or adjusting the gutter and drip edge. If a new roof is installed with a new termination or drip edge on top of the existing, it creates a higher point essentially like increasing the height of a weir in a dam. This creates a ponding issue just inside of the rear termination. When water ponds or puddles without consisting grade to flow freely from all points of the roof to the drain, it leads to accelerated deterioration at the locations of ponding which eventually leads to leakage and damage to the building. This type of occurrence is unfortunately very common in Old buildings like the historic homes of Washington DC. This occurrence though is even more common in garage roofs because people simply don’t keep an eye on the conditions of their garages as much as they do their own homes.
The picture below shows a similar small garage at the alley side of a property. The fascia board is completely rotted and now gone and the gutter and drip edge and entire determination of the roofing membrane are completely defunct and missing
Although it sounds like a big problem, and it’s not necessarily excusable, you can kind of understand why somebody might neglect their garage roof even though they would never do the same thing to the roof of their home.
The next picture below shows a pair of join garage roofs with the closer one, on the left side, and even worse condition. The interesting but problematic reality of joint buildings like this and many roams is that when one building owner doesn’t take care of their roof, it will often affect the innocent neighbor cojoined at the side.
The one on the left is shown more closely in the photo below. It’s in really bad shape.
The one on the right is shown more closely and the next photo below and you can see although it’s in much better shape with a apparently working Gutter and downspout and Sheet Metal covered fascia, it’s being negatively affected by the dilapidated roof next door. Here though, even in the case of a gutter, downspout, and fascia board or sheet metal facial covering in apparently decent condition, you can see there are problems with the construction of this roof as well. The drip edge is raised high above the top of the gutter and should really be extended to feed directly into the gutter. There are multiple layers of roofing membrane, even at this better cared for roof, and some of those layers likely have interstitial delamination.
We recommend every building owner in DC who values the longevity of their roof (and their investments) and building use a contractor who values the simple and important principles of proper roof construction like Dupont Roofing DC. Learn more about our company and the proper techniques of working with roofing on historic buildings in Washington DC here on our blog at DupontRoofingDC.com, and you can call us at (202) 840-8698 and email us at dupontroofingdc@gmail.com.
