Pryda FastFixTM Internal Wall Screw
FastFixTM Internal Wall Screw

Pryda FastFixTM Internal Wall Screw is a fast, safe, error-free installation. A smarter connection.


FastFixTM Internal Wall Screw (IWS) laterally stabilises the tops of internal walls by fixing them to the bottom chord of roof trusses.

The Internal Wall Screw has a knurled shank which ensures the screw is firm laterally against the top plate. The head-less plain shank of the screw in the top plate allows for vertical movement in the truss without transferring the load to the wall.

The product is suitable for internal applications only.


  • Quicker, safer, and more precise than a conventional hitch.
  • Reduces the risk of working at heights as IWS can be installed from the underside of roof trusses.
  • By design, the Internal Wall Screw cannot be over-driven.
  • One-piece fixing allows for the simple and easy installation process.


Screw Steel GradeASI – 1022 Steel
Screw Corrosion ProtectionYellow Zinc Chromate as per AS 1789 – 2003
Screw Size:M8 x 125mm with 5mm Hex Drive
Product CodesIWS – Screw IWSGN – Guide


The IWS must be installed vertically to enable movement of the truss. Pryda recommends that the IWG guide is used to ensure accuracy and make the installation easier.

  1. Push the positioning guide against the side of the truss bottom chord.
  2. Push the IWS into the slot in against the angled part of the guide.
  3. Using a 5mm Hex Socket, drive IWS till stable.
  4. Remove the positioning guide and drive screw home.
  5. Screw will protrude from underside of top plate by approx. 10mm for visual inspection purposes.

Install the IWS at every second truss or at 1800mm maximum spacing.

Note that the Internal Wall Screw does not replace the requirement for shear blocks.

Iws Installed Assembly 18
FastFix™ Internal Wall Screw – Guide Truss And Wall Assembly