Mike Silvers, CPRC, Silvers Systems Inc. and FRSA Director of Technical Services
As I finished last month’s column (www.floridaroof.com/frm11-22p12), I had just returned from hurricane damage reconnaissance in areas north of where Hurricane Ian made landfall. I reported on some of my early observations made just days after the hurricane and addressed issues with limited access to some hard-hit areas, noting how important it is to gather information prior to tarping and other repairs taking place. I also discussed how much information could be obtained from many types of media directly after these events. Sometimes, those two types of information gathering can converge, and with a little research and applied reasoning, there is much that can be learned.
Shortly after Hurricane Ian hit southwest Florida, I was looking at the damage on NOAA satellite imagery, slowly making my way up the coast trying to pinpoint different types of roof damage, noting the locations of buildings. I was looking for missing or damaged roof coverings, displaced air conditioning units, etc. Some damage is easy to spot, others require a closer look to find.
The roofs on a pair of condominium buildings located in Ft. Myers Beach, directly on the Gulf of Mexico, looked odd. In particular, I had trouble making out what I initially thought was a piece of strangely shaped mechanical equipment and then realized that what I was looking at was actually a couch. As I looked closer, it became clear that I wasn’t looking at a roof at all but instead at the inside of every apartment on the top floor of both buildings – kitchens, bathrooms and all. These were two good-sized buildings that had suffered a catastrophic failure of the overall roof assembly. The image made an impression. A few days later while looking at hurricane damage in the Tampa Bay Times, I was struck by a picture of these same buildings taken from a helicopter just a few days after Ian’s landfall. It was much clearer and more detailed than the NOAA imagery. You can see how compelling the above picture is. As I examined the shot closer, my attention was drawn to the houses across Estero Boulevard, behind the condos. It seemed that they weren’t as severely impacted by the storm surge as many others in this area but, even though they were protected from the wind by the much larger condo buildings, they still had significant damage. When looking closer at the shape and size of the debris near the houses it didn’t correlate with the damage to the structures. Then it occurred to me that the debris could be the roof assemblies from the condo buildings, which would indicate that the roofs may have been relatively intact when making impact with the houses. As I looked closer at a two-story house behind the others and across a canal there was similar debris. Could the roof structure have blown that far away? I couldn’t help but be curious and I hoped for some additional information.
A few days later, an opportunity to do some additional storm damage assessment presented itself. The Roofing Industry Committee on Weather Issues (RICOWI) was going to send wind investigative teams to observe damage caused by Ian and they were looking for volunteers to participate. RICOWI is a great organization funded by the Department of Energy, that is dedicated to conducting surveys to study the performance of roofing materials in extreme weather events and report their findings to the industry to help improve products and their application. RICOWI’s David Roodvoets, Jordan Loudon, members and volunteers provide an invaluable service to the industry.
I gladly agreed to spend a few days with them, as did a few FRSA members. It was another opportunity to observe and learn.
Our team was assigned investigation of steep slope roofing. We visited many sites, gathering information on all types of roof systems including shingles, tile, metal and wood shakes and shingles. We looked at damage that occurred in areas north, south and east of where Ian made landfall. These RICOWI trips confirmed many of the same successes and failures that I had observed during previous visits. Roof coverings of all types that were installed in accordance with recent editions of the Florida Building Code (FBC), which have incorporated ASCE 7-10 and 7-16, overall did very well. I’ll get back to those observations after a little more on the damage sustained on the condos I mentioned above.
With RICOWI, we gained access to Ft. Myers Beach and those condo buildings were still in the back of my mind. We worked our way south along the beach and after many stops to access all kinds of roof damage, I saw the two condo buildings I’d been looking for.
Repair work was already well underway. A new truss system had been installed and roofing had begun. Debris cleanup was in progress and a lot of the debris had been hauled away while some had been pushed aside to open up streets to traffic or moved to parking
lots for staging. One house across the street had already been demolished and hauled away. However, some of what appeared to be the condo building’s roof assembly was still laying on several of the houses.
The roof section that remained was unusual for several reasons. For one, there were two layers of plywood sheathing with an asphalt-based roof covering in between and a mechanically attached single-ply roof covering on top. I expected to see wood joists but instead was seeing trusses. I thought from seeing the walls that remained that it would probably be joists construction and that the roof-to-wall connection might have been an issue. After reviewing some Google Earth pre-hurricane pictures, it became obvious that the buildings did actually have trusses that incorporated mansards and soffits around the perimeter. All of this was now gone or at least not where it was supposed to be.
Several questions came to mind. Did the addition of a second layer of plywood that was used as an unusual type of roof recover preclude renailing of the original plywood deck? Would renailing have helped? Would the recent expansion of roof-to-wall inspections in the FBC for this type of building and the optional mitigation that it now includes, have helped in lessening the failure? How much did the presence of the mansards and soffits as well as how they were constructed and roofed, contribute to the failure? What effect would the new condominium inspection requirements that were recently adopted by the state as a response to the Surfside collapse have on the type of conditions that led to this catastrophic failure? I hope that some additional information will become available to help clarify what the failure mode was and what construction methods will be employed in making repairs.
While trying to obtain a better image of the newspaper shot that originally helped me clarify what I was seeing, I reached out to Dr. Robert Young with Western Carolina University and the credited photographer. He not only shared the image but provided a link to aerial
shots all along the impacted coastline. The viewpoint and clarity of the pictures contained are perfect for initial roof damage assessment and have added a great deal of information to our research. Looking for this kind of information often opens doors to new, unexpected resources. The degree of collaboration among those with an interest in improving the resilience of buildings is to be commended. Many thanks to Dr. Young.
I want to get back to some of my general observations. One needs to keep in mind that hard data about specific damage experienced on particular roof types and the cause of that damage are extremely hard to come by. So, for the time being, we try to reach some early preliminary conclusions using not only our own personal observations but also by discussing our observations with other professionals.
As I said earlier, roofs that have been installed since the wind resistance requirements of the FBC have been increased did very well overall regardless of roof type. With that said, many older roofs also did well, but they were outliers when looking at roofs that were approximately 20 years or older. We observed many severely damaged shingle, tile and metal roof coverings from that period. The damage to older roofs was often more catastrophic with wood exposed. Exposed wood is much less common with newer roof coverings, even when missing portions of the field of the roofs. This is possibly attributable to improved underlayments – or secondary water barrier – resistance. Several roofs were observed with very little of the primary roof covering still left in place but where a self-adhered underlayment applied direct-to-deck was present and was still providing protection from major water intrusion.
One trend was very clear from my observations. Many of those who suffered major roof damage are opting to have a self-adhered underlayment installed direct-to-deck when replacing their roofs regardless of the type of roof covering chosen. Even the historic Boca Grande Pass Lighthouse is getting the added protection that such a system provides. It seems that those who have been through a recent hurricane can see the value of having this type of underlayment as an option.
Unfortunately, this is an option that those in the High Velocity Hurricane Zone (HVHZ Miami-Dade and Broward Counties) don’t have. On December 13, the Florida Building Commission will decide if this inequity will remain when the new 2023 8th Edition of the Florida Building Code is adopted or if they will follow the guidance of the Commision’s Roofing Technical Advisory Committee and the roofing industry coalition and vote to standardize underlayment options throughout Florida. Self-adhered underlayment applied directly to the deck is the only underlayment option that qualifies for a secondary water resistance mitigation credit from Florida’s property insurers. It will also help reduce claim damages that affect insurance rates for all Floridians. One of FRSA’s past Presidents recently asked “Why is it only the people with no experience with this installation method are the ones pushing back against its adoption?” Great question!
Mike Silvers, CPRC is owner of Silvers Systems Inc., and is consulting with FRSA as Director of Technical Services. Mike is an FRSA Past President, Life Member and Campanella Award recipient and brings over 40 years of industry knowledge and experience to FRSA’s team.
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