Fastening boundary joists and baluster posts onto decking frames can be overly complicated and costly. Common methods use a combination of straps, coach screws and bolts and, more recently, systems of brackets and screws that were developed to comply with NZS 3604. These systems are very labour intensive and often end up with an unattractive finish around the outside and underside of the deck.

SPAX has recognised the limitations and complexity of the current systems and developed an innovative solution. SPAX has developed and tested a new bracket-less boundary joist and post-fixing solution, which is remarkably simple to use, aesthetically appealing and provides significant time and labour cost savings. Trials have shown that the SPAX solution is more than three times faster than other common methods.

The SPAX solution simply uses a washer head screw to clamp the components tightly together. SPAX fully threaded stainless-steel screws are then installed at a 15 degree angle into the end grain of the deck joist to provide an extremely strong and rigid connection. This is done easily with the SPAX pre-drill guide which enables accurate and fast installation at the correct angle. The job is completed by fastening the post to the boundary joist with SPAX fully threaded countersunk stainless-steel screws, providing both a strong connection and an attractive finish.

Stringent testing was conducted locally in New Zealand. The results confirmed that the SPAX solution fully complies with NZS 3604 and clause B1 of the New Zealand Building Code, as well as the strength and deflection requirements of AS/NZS 1170. A PS1 Producer Statement is available for Building Consent Authorities.