Ferrous Metal Rooftop Elements and Upkeep – PART VI

In the past several weeks, on our blog, we have been looking at specific facets of challenges and upkeep requirements of non-roof items on rooftops, in a series on flat roof problems associated with ferrous metal non-roof components.  These are elements that are not actually part of the roof itself. The roof itself will include elements such as the field membrane and the elements of terminations and even elements of flanges or prefabricated rubber type materials to fit around penetrations. These items are actually different and separate from the rooftop itself yet they are installed on top of the rooftop and often have elements of mounting or connection which go through the roof itself. 

Today, we will talk about electrical cabling and related support  systems, and in the next article we will discuss the implications of ferrous metals and penetrations through roofs for low volt cabling connections and mounting of photovoltaic solar panels on rooftops and some of the potential problems associated with those elements on roofs and methods of preventing leakage and required upkeep.

The outline of this series of articles follows:

    • Common types of non-roof components found or flat roofs
      • Access Systems 
      • Historic Brick chimneys
      • Air Exhaust systems
      • HVAC systems
      • Electrical power distribution
  • Low Volt and communication wiring and satellite / antennas
    • PV Panels and mounting structures
    • Guardrails and fall protection systems
  • Roofing problems caused by oxidation of ferrous metals
    • Delamination 
    • Staining and bondability
    • Structural component failure
    • Leakage through metals
  • Methods of Repair and sustainability 
    • Standard Coatings
    • Substrate preparation
    • Advanced re-coatings
    • Special roofing provisions

Low Volt and communication wiring and satellite / antennas

Low voltage communication wiring in Satellite antennas and Associated Equipment May appear and be used on rooftops in several different types of configurations, but the picture below shows an example of a common type of installation of a satellite dish. this particular satellite dish is set onto a metal sled which is not fastened in place, just set loose but shaped to allow for the installation of cementitious pavers. and this particular case, the building owner or Television or satellite service providerHas just used CMU cinder blocks in lieu of a proper cementitious paver. This kind of works, but it isn’t using the equipment as it was intended. Also, in this particular example a slipsheet, required by the building code to protect the roof membrane from abrasion and slow deterioration from the metal sled, has been omitted and not installed.

low voltage communication on roof

The adjacent picture shows a newly installed TPO membrane by our company.  The roof is strong and well installed, yet there is a random looking wire running across the rooftop.  

tpo membrane ferrous metal roof
Low volt cabling actually is required to be mounted, by the building Code, so this was incorrectly installed by the cable man,yet installations like this are unfortunately very common

Another picture below shows a pipe sleeve that penetrates through a rooftop membrane. This is not an actual pipe for water or any type of liquids, it’s just a piece of pipe material that has been used as a sleeve for wires to pass through the inside of the building to the rooftop. There’s nothing inherently wrong with using a pipe as a sleeve as has been done in the picture below, but we recommend the installation of a gooseneck or 90° combined Bend in the pipe so that rain water does not fall into the top of the pipe and then down into the building. In this case sealants have been applied around the wiring but those sealants have been damaged by the movement inherent in loose wiring and have also deteriorated from exposure to ultraviolet rays in sunlight.

The installer of the wiring has literally wrapped electrical tape around the point where the wire comes through the pipe sleeve. electrical tape is not waterproof and when wrapped around a configuration securing wire in place it won’t actually create a waterproof membrane around the orifice of the pipe. Other installation methods are available which will work much better.  One preferred method is a gooseneck, as we mentioned. other methods such as a pitch pocket or even filling this sleeve with a portable sealant would be better than the current installation.

electrical tape on wiring

The next picture below shows a similar but yet even worse installation. This particular sleeve isn’t really a pipe or any type of sleeve at all, it’s just a membrane that has been wrapped around a combination of low voltage wiring and line voltage wiring and low pressure and high pressure refrigerant lines used to feed to a condenser unit. The condenser unit is set unevenly on the roof surface without a platform or stand. There are many problems with the overall installation but in the case of the low voltage line shown here, the sheathing around the cabling has deteriorated from exposure to ultraviolet rays in sunlight.

bad installation of electrical devices on rooftop

Smart and proactive replacement, construction, upkeep and maintenance of low slope roof and mansard roof systems requires an enthusiastic interest and understanding of historical methodologies, waterproofing principles, and building science.   Here in Washington DC, historic and modern residential and commercial buildings are extremely expensive and the roof and related systems provide the shield that preserves the building. 

We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the value of quality construction and building maintenance, and develop a relationship with our company.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the roof and related systems of your building in Washington DC, contact us or fill out the webform below and drop us a line.  We will be in touch if we can help.

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