Ferrous Metal Rooftop Elements and Upkeep – PART VIII

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 roof membrane itself yet they are installed on top of the roof and often have elements of mounting or connection which go through the roof membrane itself. 

Today, we will talk about guardrails and fall protection systems, and in the next article we will discuss the implications of ferrous metals and inherent points of deterioration or failure 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

Guardrails and fall protection systems

The rules around the requirements for guardrails and fall protection systems are pretty complicated because different sets of rules with a variety of requirements apply to each configuration or different type of installation. There are some elements that are relatively consistent though. One example is that in most guard systems a balustrade or full panel is required. In most cases between balusters, the interstitial space must be less than 4 in. The building code commentary, not part of the actual code itself, essentially explains that babies can fit their heads between spaces that are larger than about that size, so for safety reasons larger spaces are more dangerous.  Like a rat, if a baby can squeeze their head through a space, they can wriggle the rest of their body through as well and then fall off a higher platform, deck, or stairway.

The picture below shows a guardrail installed on a rooftop deck.  Each post in this installation is sealed to the modified bitumen roof membrane at a pitch pocket. A flat roof pitch pocket is a component used to seal around penetrations on flat roofs. 

pitch pockets

Pitch pockets serve to create a watertight seal and protect against water infiltration in areas where various roof-mounted equipment or pipes pass through the roof’s surface. The purpose of a pitch pocket is to accommodate the irregular shapes and sizes of these penetrations, such as HVAC units, vent pipes, or conduit, ensuring a secure, waterproof seal. A pitch pocket typically consists of a base material, often made of metal or rubber, and a sealant compound. This combination allows for flexibility and adaptability to fit different shapes and sizes of penetrations. Unlike traditional caulking, which may crack or deteriorate over time, pitch pockets provide a more robust and long-lasting solution. They are designed to expand and contract with temperature variations, preventing cracks and maintaining a tight seal. Pitch pockets work better than caulking because they can accommodate irregular shapes and offer greater resistance to the stresses placed on the seal due to weather and building movement. Regular roof membranes alone cannot effectively seal around penetrations because they are not designed to accommodate the dynamic forces and irregular shapes associated with roof penetrations. Pitch pockets, on the other hand, are specialized for this purpose, providing a reliable and lasting solution for waterproofing flat roofs with multiple penetrations, making them a preferred choice in the construction and maintenance of commercial and industrial flat roofs.

The axis steer ladder shown in the image below is used to get from a rear deck to the main high flat rooftop of a historic row home. Like many historic row homes in Washington DC, it’s important to be able to access the roof and you can reach the roof through an extension ladder but in this particularly tall row home  with 3.5 stories above ground, an enormous 60 ft extension ladder would be required to reach the roof. 60 ft step ladders are extremely heavy and unwieldy and it requires multiple people just to set them in place. For that reason in this particular case it’s much better to have a permanently built access stairway. we talked about access stairs on our first segment in this series, but this particular stair is different than some others because the connecting top gooseneck or return of the steel ladder also works like a guard,  giving a user the ability to stabilize themselves as they make the transition from the ladder to the rooftop. 

axis steel ladder ferrous metal rooftop

In this particular case, pitch pocket was not used, instead the modified bitumen membrane, alone by itself was used to seal around the steel penetration through the roof membrane at this location, the ferrous metal oxidizes and therefore allows the membrane to separate from where it is bonded to the metal. 

In the picture below you can see the significant amount of oxidation and rust throughout the access ladder.

oxidation and rust

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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