Tie down and hold down rods are integral in securing the roof structure and bearing ends of beams to limit the potential hazard of roof uplift during storms and severe weather. Tie down rods transmit the uplift forces caused by wind down through the walls into the ground. Wall systems whether brick or timber must be properly anchored to the sub-floor; this is especially imported either side of openings where increased uplift forces can result. It is important to understand the requirements for tie down rods as specified by your engineer and the Australian Standards and Australian Building Code. The requirements do vary depending on the wind classification for your area.
Tie down rods come in a variety of configurations; the four most common types are normally threaded at the top for bolting or welded to steel members while the bottom is typically configured with: