Mike Silvers, CPRC, Silvers Systems Inc. & FRSA Director of Technical Services
The so called 25 Percent Rule continues to cause a certain amount of confusion for building owners, contractors, inspectors and insurers. A recent change (shown below) went into effect on January 1, when the 2017 Florida Building Code, Sixth Edition became the new code. At first glance it doesn’t look like much of a change however, on closer examination, it is quite significant. The previous language required replacement of the total roof only if the balance didn’t conform to the current code. The new language states it is to be replaced to conform to the current code. So now the entire roof area or section must be replaced regardless of the age or condition of the undamaged portion. This requirement is not limited to damaged roofs; it applies to repairs, replacement or
recovers regardless of the reason. As an example, it would apply if a portion of a new roof (more than 25%) needed to be replaced under warranty due to misapplication.
708.1.1
Not more than 25 percent of the total roof area or roof section of any existing building or structure shall be repaired, replaced or
recovered in any 12-month period unless the entire roofing system or roof section conforms to requirements of this code.
706.1.1
Not more than 25 percent of the total roof area or roof section of any existing building or structure shall be repaired, replaced
or recovered in any 12-month period unless the entire existing roofing system or roof section is replaced to conform to requirements
of this code.
Another area of confusion concerns the definition of roof area or roof section. A roof section is defined in the code (shown below). An existing expansion joint would create a separate roof section. A parapet or dividing wall also would. Short offsets that require flashing would as well. This condition is common in townhome type apartments. Changes of elevation such as the roof on a one-story section and a two-story section would also be considered a separate section. So, if half the roof on a two-story section needs to be replaced, the entire two-story section must be replaced, but the single-story section would not have to be done. Valleys, hips and ridges do not create a separate section, so if one side of a rectangular- shaped (more than 25%), single story hip roof needs to be replaced, it would require all four sides to be done. Changes of roof type also create separate roof sections. So, if a house with modified bitumen flat deck needs to be replaced, the shingle section doesn’t have to be replaced, even if the flat section is more than 25% of the entire roof.
Roof Section. A separating or division of a roof area by existing expansion joints, parapet walls, flashing (excluding valley), difference of elevation (excluding hips and ridges), roof type or legal description; not including the roof area required for a proper tie-off with an existing system.
The confusion caused by this change is a great example of how just a few added or changed words in the code can have major implications. If you have specific questions or comments on this or other sections of the code, please contact me. I will do my best to answer your question or listen to any concerns.
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