Managing Vines Growing Up Walls: Risks to Roofs and Structures
Here, In Washington DC, there’s many examples of buildings that have vines growing on the exterior brick facade, but in some cases, those vines grow all the way up to the rooftop, and into places where they can cause physical damage and even leakage problems. In the lower areas of the building, such as the windows and or exhaust vents, vines could also cause problems. Particularly if vines grow around ac units, they can reduce the efficiency and cause a significant amount of extra additional electrical energy consumption to create a commensurate level of cooling or heating in a home.
Where Vines grow into the edges of a roof though, it can cause different types of problems. In the worst of these types of cases, the vines growing into and through parts of the edges of the roof can cause a separation of the roof from its subcomponent materials or from different parts of the building which can lead to leakage and flooding. In many cases animals and ridents will also follow these entry points into parts of the building where they don’t belong.
The picture below shows a rooftop gutter, almost completely engulfed with a Virgina Creeper vine. Despite the plant’s name which makes it sound like it’s just comes from Virginia, this particular plant is endemic to almost all of the eastern part of the contiguous United states. Like other types of climbing vines, this particular vine groups with small tendrils tendrils that will grip to wall surfaces as the plant continues to aggressively grow.
This plant could be grown intentionally or ornamentally, but the plant will grow aggressively and take over areas of properties in yards if not properly maintained. For people who don’t work with roofs every single day, it might seem that roof systems are relatively simple. We might agree, they aren’t extremely complicated, necessarily, but they’re often more than just a simple continuous system or application.
Most roofs have a variety of different elements, connection points, penetrations, and perimeter details that in some cases offer opportunities for plants to grow between overlaid concentric or layered elements. When plants grow between many of these different types of elements in the roof system or adjacent to the roof system, they can spread the materials apart.
The same issue occurs in the ground, down at the foundation of the building with plant roots. As plant roots grow, they can expand and actually grow or thicken with such force that they can break apart stone and concrete. Plant roots often will lift concrete up several inches. We see this commonly occur here in DC at the sidewalks. It’s great to have a green space that makes the concrete jungle of our city feel less hard and cold. Plants bring a bit of a soft warmth to an environment, particularly an urban environment, which otherwise can feel very bleak.
For these reasons, it’s really nice to have the city streets and sidewalks lined with trees, but the trees also cause damage to the heavy concrete because the roots grow with such strength and force that the concrete can’t resist the pressure to break and displace. The same type of issue occurs with building walls and roofs, particularly where the walls and roofs meet together at the edges of the roof.
Looking at these pictures at the low angle along the rear termination of the modified bitumen roof, where the drip edge flashing transfers the roof into the gutter, it’s easy to imagine that these vines will cause problems for water drainage. Water drainage problems like this will be exacerbated when there is significant leaf fall and or icy and snowy conditions in the winter months.
Effectively, these vines are creating a net which will block and build up elements which will stop the flow of water. As those elements build up, particularly when there are natural winter conditions of freeze-thaw cycles, the continued build up, coincident with iterations of freezing temperatures can create ice damming which will cause leakage into the back of the building.
The next picture below shows a different building with a similar issue. In this particular case, the ivy hasn’t reached the gutter yet. But as time goes by without maintenance or mitigation, the vines will continue to grow and cause damage to the rear gutter. In this case, you can see the gutter is already excessively sloped, it looks like it’s almost already detached from the initially intended fascia mounting board.
The next picture below shows the sidewall of another building here in Washington DC. At this particular location, the wall was once largely covered in vines. The vines have now almost all been completely removed. At least these vines have now been killed, but the remnants of those vines still remain attached to the walls. Overtime, those decaying remnants will continue to break down and fall off in small pieces bit by bit, but full scale removal of the tendrils and the branches of the vines themselves can be difficult.
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. We are happy to help and at least talk through options.
