A Closer Look at Rooftop Satellite Sleds
This past week we began looking at the topic of satellite dish sleds on rooftops. In most cases these elements basically just sit up on top of the roof passively. In some cases, over time, they can cause damage. More importantly than anything else though, it’s a simple building code requirement to follow the manufacturer’s installation requirements. We try to use the building code as a minimum set of standards. In most cases, particularly with historic buildings, the building code doesn’t always fit perfectly.
In some cases though it’s relatively straightforward. This is one of those cases where the building code says to follow the manufacturers installation instructions for the roof membrane. The manufacturers have a tendency to write the written requirements for installation so that the installation is of high quality and has relatively stringent standards. Pretty consistently, the manufacturers require that any elements resting or set upon the rooftop be separated from the roof membrane by at least a slip sheet.
A slip sheet can be something as simple as a cut portion of a remnant of the roof membrane. In most cases when we install this type of membrane, to avoid an issue with compatibility we will install the slip sheet face down. Once the slip sheet is set on top of the roof the sled can be installed back on top of that slip sheet.
In some cases, when installing a slip sheet and lifting and resetting the satellite dish, it may cause the signal to need to be recalibrated. In many cases, the calibration of the satellite dishes can be done with a process as simple as just being on the phone with the client while they’re inside the house while we adjust the satellite dish by moving it slightly on top of the roof.
In other cases where the conditions are more sensitive, the client may need to contact the service provider directly and coordinate with them to come back to the property to adjust the unit. Generally, they have a similar process and adjust it just by moving it slightly with a calibration device that they connect from the rooftop. In some cases the service provider will charge the client for this type of service but in other cases we can help while we’re there with hardly any time or expense required, specifically while we’re doing other work simultaneously.
In this past week’s blog article we discussed some of the characteristics of a modified bitumen single-ply roof membrane system. This is a very common type of low slope roof system. It’s also relatively common for satellite dishes to be set upon the rooftop in this type of way. For that reason, it’s important to have residual routine type of upkeep checks by a company like ours to look at the details. The roof can be protected by simply adding something like a slip sheet between the sled or frame of the satellite dish mounting and the rooftop membrane
In a picture below we show a very similar type of installation but different. In this case, they have not used a sled. Instead, they bolted the satellite dish directly down to the rooftop. In this case, they bolted through the modified bitumen membrane. Unlike the membrane we looked at in the pictures above and this past week, the membrane shown in the picture below is similar but different.
The membrane shown below is a modified bitumen smooth membrane. It happens to be painted with an aluminum paint. Aluminum paints have a silver or grayish type of color and provide a degree of reflectivity but not nearly as much reflectivity as you would find with an elastomeric type coating. Elastomeric coatings are generally white in color and have a much higher degree of reflectivity, as high as over 90%. We don’t always believe these statistics because we think they’re a little bit counterintuitive but nonetheless we do recognize that the amount of reflectivity is much higher with a white painted roof coating.
Here, since they bolted the satellite dish mounting plate directly through the rooftop membrane, it means there are fastener holes in the horizontal or near horizontal low-slope area of the roof deck. We always recommend fasteners NOT be installed in this low-slope portion of the roof membrane. In fact, we recommend all elements be set into a pitch pocket, with an approved covering, and or laid underneath the successively overlaid membrane of the modified bitumen roof. Here, this seems to break all of those rules.
In a case like this, high performance coatings, different and largely unrelated to typical roof coatings, can be installed on top of the fastener locations. However, a particular script of preparatory steps should be taken as well to encourage good adhesion in bonding to the substrate.
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.
