Plasterboard bracing systems play a significant role in the construction of residential buildings in New Zealand. The use of these systems has developed over time, changing the way homes are built, making the process faster, easier, and more affordable. This article provides a brief history of plasterboard bracing in New Zealand and its evolution. 

Plasterboard was first introduced in New Zealand in the early-20th century. At the time, it was considered a novel material that promised to simplify the building process. The early plasterboards were used as a covering for walls and ceilings, as an alternative to lath and plaster linings.  It wasn't until the 1970s that the material's bracing properties were first investigated. 

In the 1970s, engineers and builders in New Zealand realised that plasterboard could be used as a bracing material. At the time, research was also carried out to investigate the seismic performance of residential buildings, and included testing of then typical construction methods, such as timber framing with cut-in timber braces, without linings in place. The results did not line up with the observed performance of building in actual earthquakes.  Light timber framed buildings had performed better than the results suggested.  Further testing was carried out with linings in place, and it was concluded that plasterboard linings significantly contribute to bracing resistance.   

This is no real surprise.  Once all sheets are taped and stopped, the plasterboard lining system is strong and very stiff.  During an earthquake, or high winds, the stiffest element will be subjected to lateral forces first, whether designed to resist them or not.  If a bracing design relies on more flexible elements, the stiffer plasterboard system will still contribute, but can suffer damage before forces are transferred, resulting in cracked joints and possible sheet damage.  As the wall is loaded it will deflect, only then allowing bracing elements like cut in timber bracing, or steel straps, to resist applied forces.  The risk of damage is much reduced when the plasterboard lining system is designed to accept the imposed wind and earthquake forces.  When correctly applied, plasterboard bracing systems will save on other bracing materials, and deliver a building less prone to movement cracks over its life. 

The use of plasterboard bracing was included in the early developments of the non-specific design Standard NZS3604 – Timber Framed Buildings. Our team has continued to innovate and developed a range of plasterboard bracing systems with various levels of performance, as well as free design software to simplify the specification and consenting processes. Higher levels of performance mean that associated plasterboard characteristics need to be significantly better that the base minimum levels called for in Standard AS2588 –Gypsum Plasterboard. 

The development of plasterboard for bracing applications was a significant breakthrough in the construction industry, as it meant that walls could be built faster and more easily, without the need for additional timber or steel braces. Plasterboard bracing systems are common in New Zealand, and widely used in residential construction today.

The continued use of plasterboard bracing in residential construction is a testament to its versatility and effectiveness.