Wind Warranty vs. Wind Uplift

Course Description / Learning Objectives:

  • Understand that there is a difference between wind speeds and wind pressure on the roofing system
  • Taking a look at the differences and suggest ways in which specifications can be written to meet the local code requirement 
  • The building code does not require that a warranty is issued! To learn more about which type of warranty is best suited for your building requirements, watch this recording from our June 22nd 2017 live webinar.

Please note that AIA and RCI credit can not be earned for watching the recording. Please provide your email to get updated on any upcoming building construction webinars.


About The Presenter:

Joe Schwetz Headshot

Our industry expert, Joe Schwetz VP of Technical Services, will be presenting and answering your wind warranty questions.

Mr. Schwetz is one of the most respected individuals in the roofing industry. He is currently involved with a handful of committees, and in 2015 he received the American Society for Testing and Materials (ASTM) International Award of Merit for his work with the E60 Committee.

Watch the webinar recording now! Stay updated on upcoming CEUs webinars by providing us with your email address.   

Sika Roofing, a Division of Sika Corporation, is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) cannot be earned for the above webinar as the live event has concluded. However, we are happy to schedule a Lunch and Learn for your team!  

Webinar Questions and Answers

1. If using the FM factor of safety of 2 and ASCE 7-10 you would convert the ASCE 7-10 ultimate wind load to the allowable load (multiply the ultimate pressure by x .6)?

For ASCE 10: Do the calculation by multiplying .6 then bring it to the allowable then it is building code. Now if using FM: you have to follow FM criteria. If FM using 0-5, they are following the allowable but they do add other safety factors on throughout calculation. One of them being automatic Sika factor of 2. If it is FM, calculate for FM and install for that. With the 7-10 version, because it is ultimate always bring it back to allowable.  

2. How do green roof systems meet the code on up lift?

This is the current issue with a vegetated roof. Vegetated roofs are strictly ballasted assemblies. The way to get around this is that we will actually install a roof system that has been tested and approved to pressure. We can install that however the vegetated part, the overburden, you can’t really test that but as long as the roof coverage itself is tested that is probably the safest approach to do. We have a document that talks about ballasting systems so you can follow the guidelines.  

3. Are there any differences between IBC 2012 and the current 2015 version?

From the wind perspective, it’s almost exactly word for word. 2012 and 2015 are following the 7-10 version however anything earlier than 2012 version is using 0-5.

4. How does something like Rhinobond with the smaller fastener distance affect the testing and rating?

We test Rhinobond per difference densities or grid patterns. It is the same thing if we were doing an inseam fastening pattern or an adhered fastening pattern. When we build Rhinobond system, we have a 2x2 or 2x3 grid, we test that at a lab and that becomes an accepted system and we can codify that.  

5. What will that 4th zone be?

Basically, it's going to be an additional perimeter zone. It will be called a prime zone, more specifically a three prime zone. If you’re buying ASCE 17, please contact me for further details.  

6. With code required increases of insulation R values, how will this affect the performance of adhered roof systems because the more layers of insulation increases the risk of workmanship related failures. Should uplift testing be required on these roofs?

If you look at the system and pull out an insulation, there is a test program depending on the manufacturer’s design of the system. In the program, you will see that a lot of them will be from 1 to .06 inches but the most of the listings in this industry has insulation layers up to 12 and a half inches. So if it is a mechanically fastened system, we can count system fasteners and hope that they are setting fast, straight, and true. If adhering system, then it’s a workmanship issue and that is something we as manufactures should try to keep an eye on. Make sure everything is done right, work with contractor and train them but this is where those safety factors come in. You as the designer might think about increasing the safety factors if an assembly has layers of insulation to overcome the possible workmanship issues. But generally speaking if the problem that tends to be an installation issue more so than product, they always keep the safety factor at least 2.  

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