Rooftop Satellite Sleds installation
The topic of satellite sleds has come up a few times or at least been mentioned here on our website and blog. Satellites can be installed in a variety of different ways, one of the common types of methods for installation is installing the satellite dish on a metal frame. The metal frame is not directly attached to or through the rooftop membrane. We like this method overall because it’s at least much better from a life cycle maintenance upkeep perspective to not have the satellite dish bolted through the roof itself. This method isn’t perfect though either.
Often the satellite or data communications cable installers don’t install the sled properly. It isn’t a really complex job, but the installers should set the sled on top of a sacrificial mat instead of setting it directly on the rooftop surface.
Here in the next photo below, you can see that the frame of the satellite sled is sitting directly on top of the surface of the granules. This is a modified bitumen low slope roof. There are several different types of modified bitumen membranes, but this one happens to be an APP granulated modified bitumen membrane. The granules on top of the membrane are installed to protect the roof material from accelerated deterioration associated with exposure to ultraviolet rays.
In this type of usage, these granules reflect a degree and absorb a degree of that energy that comes from the sunlight. The important part though is that they protect the substrate membrane from that UV. The granules remain largely undamaged whereas the membrane itself would be significantly damaged over time by exposure to UV.
There are multiple different types of coatings and or systems that can be applied to a roof membrane to help it protect or deter damage related to exposure to UV rays. Here, the granules are just one type of application. These granules work pretty well, in most cases, to help make the roof upkeep a bit more passive.
With one of the alternative types of membranes, a modified bitumen smooth membrane, constant repainting is required. In some cases those membranes need to be repainted every 3 to 9 years. Although the range is a relatively wide range, because many characteristics and conditions can influence the resulting duration, the point is, the paint can be expected to have a relatively short lifespan.
In these pictures, you can see that the underside of the steel dish sled is directly in contact with the roof membrane. In most cases, the sled won’t cause extreme damage or gouging or cutting of the roof membrane. The problem is that, only over time, with micro-movements that are typical with things attached to a roof system, the roof will begin to experience some wear and deterioration.
As well, and the area directly under the frame of the satellite dish sled, water and debris will begin to accumulate. Water that’s trapped in that area underside will eventually dry out with rising temperatures and continued cycles of dry weather. However the time period required for dry out is extended because water that enters into that area is not in contact or exposed to sunlight. Even though water doesn’t get out from that space easily, it will enter into the space almost every time there’s even a small degree of precipitation.
Pretty much across the board, the modern low-slope roof membranes, the most common type of roof memories installed on flat roofs, are relatively durable. There are varying degrees of durability between the different types of roof membranes, but most classifications or groups of roof membranes have moderate to high strength and can withstand relatively serious impact or force applied from other elements. The issue here is just that over time, with repeated, daily cyclical abrasion against the surface of the roof, it can cause the roof to wear out at the acute points where the sled is in contact with the membrane.
In this coming week, we’ll look at the different pictures and angles of the same satellite dish sled. Although this is one of the common types of installation of rooftop satellite dishes, it’s not the only type available. In the week after next we’ll also take a look at some old TV antennas that still remain as remnants of the past. In many cases these old antennas are made from large aluminum frames that are mounted to chimneys and other parts or elements on the rooftop.
Nowadays, we recommend the best thing is to remove these items. As well with defunct or abandoned satellite dishes, we also recommend removal, but in many cases the owners or clients responsible for the roof of the building are not even aware. In most cases, we also make an effort to notify and inform the clients of the existence of this type of old or outdated system on the rooftop.
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.
