Roof Decking Screws

Hi Bill:

Here is the screw tip on the 8.5 inch screws:

Self tapping screw thread

This screw does not grab the decking like the timberlock.  The absence of thread on the last 1/4 inch prevents early thread engagement.  When we press hard enough to penetrate the 1/4 inch – we can only sink a small amount of thread.  When we release, the thread pulls free, and there is never enough bite to pull the chipboard into place and hold it.

With a timberlock, thread below, we get bite very early and the assembly pulls down firmly.  Except Timberlocks are incompatible because, the heads stand too tall for metal roofing, and do not have a 9 inch length available.

VS a timberlock.