Installation Manual

DynoRaxx Evolution PR Guide to Code Compliant Installation
20 | P a g e 8 6 6 . 6 2 0 . 2 4 1 0 | d y n o r a x x . c o m
VI. Roof Mounting:
The Evolution PR system is designed to be attached directly to the roof deck of the customer’s house. With
the preliminary analysis of the systems loading completed, it is necessary to work out the details for the roof
mounting, in order to insure a proper and secure installation of the racking system.
The main concern of the roof mounting analysis is the withdrawal load. The withdrawal load is the force
required to remove a screw by withdrawing in line with the screw. This force is directly proportional to the
diameter of the screw as well as its length. Furthermore, the withdrawal load is also dependent on the type of
wood used in the roofing. Hence, a safety factor of 4 is recommended to account for the many different types
of materials used.
Evolution PR utilizes the TEKS self tapping screw. This screw is threaded throughout its length and has a
water-resistant seal. These fasteners are drilled through the provided holes on the Evolution PR directly into
the roof decking. In the table shown below, the specific values of the pull out strengths are given against
different roof decks.
Pull-Out Test Results, Average Ultimate Failure
Values
Material Used
Pull out Strength (lbs)
SPF #2
1080
CDX ½”
520
CDX 5/8”
430
CDX ¾”
718
OSB 7/16”
213
OSB 15/32”
223
OSB 19/32”
301
Source: http://www.atlasfasteners.com/woodmetal.htm
SPF is framing lumber, CDX is plywood, and OSB is strands of wood hot pressed together.
The Evolution PR has a 1/8” layer of butyl mastic sealing tape on its bottom and five predrilled holes for deck
screws. Because pull out strength is a linear function of the screws, the Evolution PR system has enough holes
to account for the safety factor of 4.