Over the past few weeks, we looked at a historic row home roof where the chimney had deteriorated to the point that the bricks were spalled and chunks of the bricks were falling onto the rooftop surface. We can consider that a deleterious and serious condition because When contractors get up on the roof, particularly contractors who are not roofers, they have a tendency to walk on top of those chunks of bricks. Walking on top of those chunks of bricks can damage the roof below because when they walk right on top of the brick chunks, they can force the hard and jagged edges of those bricks to puncture through the roof membrane.
Not all roof contractors are as conscientious as our company and particularly when it comes to other contractors such as electricians and mechanical contractors, they don’t often care much about the roof because it’s not part of their actual work. It’s important that the contractors protect the roof but it’s probably an even better or more proactive idea to just simply remove those brick chunks first and fix the deteriorating chimney before other contractors are up there on the roof.
Today, we’re going to take a look at a similar but unrelated topic. We are looking at a protective sacrificial surface that has been applied on top of the low slope roof to protect it from the contractors walking on top of the flat roof.
The tube steel post shown in this picture stands above the roof itself which allows the membrane to terminate against the sides of the tubes. These particular steel elements are highly conductive to electricity and a bit dangerous if that electricity comes in the form of lightning. Because the building is relatively tall, taller than many of the neighboring buildings, the risks of lightning strikes is increased and the cables that run from these posts are for electrical bonding so that if it does have any electromagnetic charge, that charge will return to Earth ground.
It might be a little bit difficult to visually identify the protective mat in the photo below, because both the roof membrane and the protective mat are nearly the same dark color, but the protective mat has dimples that run across the walking surface to add traction and you can identify this textural difference.
We’re at a different area of a roof, with a different color substrate membrane. Here, the walking mat stands out more distinctly. The walking mat protects the roof membrane below and kind of acts a bit like a sacrificial surface. For example, if a plumbing contractor needs to walk around on the roof or an electrician needs to access areas of the roof, they can walk on this protective mat and even if they have sharp objects like screws or fasteners in their shoe soles, it won’t cut or scratch through the roof membrane.
Instead it will damage the protective mat which will, in turn, protect the substrate roof membrane from this damage. Damage like this can cause serious interior destruction to other elements of the building. Leaks, of almost any type, can cause infiltration and rot to many different types of susceptible materials such as framing materials, drywall, insulation, and building finishes.
The closer view of that same protective mat follows below. You can see the pattern that is set into this material. One of the main problems that leads to accelerated deterioration and damage of most roofing materials is exposure to ultraviolet rays. Ultraviolet rays are present in almost all types of sunlight. Most of the flexible and resilient types of materials used in low-slope or flat roofing have significant susceptibility to destruction or damage from exposure to ultraviolet rays.
Overtime, these ultraviolet rays will break down the materials that constitute or make up the polymers and or other substrate components of the roof membranes. This protective mat will also deteriorate on a relatively accelerated schedule, but it still protects the substrate roof membrane in the meantime, from damage from foot traffic and to a degree from damage from exposure to ultraviolet rays.
The next picture below shows the long path created by this protective mat
The following picture below shows this mat more closely.
We provide this information here on our blog, and our website, to help our customers and future clients, and 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. Our company specializes in flat roofing here in Washington DC and we’re happy to help building owners of almost all types.
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.
