HDU holdowns are pre-deflected during the manufacturing process, virtually eliminating deflection under load due to material stretch. They use Strong-Drive® SDS Heavy-Duty Connector screws which install easily, reduce fastener slip and provide a greater net section when compared to bolts.
The DTT tension ties are designed for lighter-duty holdown applications on single 2x posts. The DTT1Z is installed with nails or Strong-Drive SD Connector screws and the DTT2Z installs easily with Strong-Drive SDS Heavy-Duty Connector screws (included). The DTT1Z holdowns have been tested for use in designed shearwalls and prescriptive braced wall panels as well as prescriptive wood-deck applications (see DTT deck tension ties for deck applications).
For more information on holdown options, contact Simpson Strong-Tie.
For stainless-steel fasteners, see Fastener Types and Sizes Specified for Simpson Strong-Tie Connectors.
Many of these products are approved for installation with Strong-Drive® SD Connector screws.