Stone wool insulation has emerged as a game-changer for lightweight timber-frame and cross-laminated timber construction, delivering exceptional fire safety, thermal performance, and acoustic control. It comes after a series of CSIRO tests at the North Ryde facility showed that timber-framed walls and cross-laminated timber floor panels clad in stone wool — and not plasterboard — can successfully withstand fire for more than two and a half hours (for timber frame) and three hours (for cross-laminated timber), smashing the 45‑minute minimum set by the Australian National Construction Code’s fire‑protection timber requirements.
The findings — revealed to hundreds of architects, engineers and developers during the largest WoodSolutions webinar in years — represent a huge leap in building materials technology and could deliver substantial cost savings in timber construction. Wood Central understands that the results position stone wool as a high-performance alternative to conventional fire-grade plasterboard, with potential applications spanning mid-rise timber-framed buildings to residential properties in bushfire-prone zones.
In CSIRO testing, DCTech VulcanWool stone wool delivered 151 minutes of fire resistance for lightweight timber framing, surpassing NCC requirements while enhancing thermal and acoustic performance. Footage courtesy of @DCTech
Andrew Dunn, CEO of the Timber Development Association, said the tests were designed to measure the interface temperature between the stone wool and the timber. “The standard requires the temperature to remain below 300°C for critical durations — 45 minutes for external walls, 20 minutes for stairways, lofts and shafts, and 30 minutes for all other areas,” he told Wood Central today. “Over the years, I’ve observed numerous timber tests, but the stone wool performance was extraordinary.”
It easily outperformed traditional fire‑grade plasterboard. Stone wool offers superior fire protection while providing excellent acoustic and thermal insulation. This could potentially revolutionise construction costs for mass timber and timber‑framed buildings.
Andrew Dunn, together with Andy Russell from Proctor Australia/DCTech and Jeremy Church from NeXTimber® by Timberlink, presented the findings to hundreds of participants at today’s WoodSolutions webinar, Stone Wool Fire Resistance.
The AS 1530.4‑compliant trials were supported by DCTech, Forest Wood Products Australia, pro clima, NeXTimber® by Timberlink, ROCKWOOL Australia and Xlam Australia. Researchers tested a 90mm x 75mm timber frame wrapped in 75mm of ROCKWOOL and DCTech VulchWool, along with 140mm cross‑laminated timber panels supplied by NeXTimber® and Xlam Australia.
Jeremy Church, General Manager of NeXTimber, said the results are especially promising for residential developments such as build‑to‑rent apartments and student accommodation — both growing markets for CLT floors: “The bonus is that typically for those short spans in residential buildings, you would require some form of insulated suspended ceiling to meet acoustic requirements,” he told Wood Central. “With stone wool, there is the potential to improve your acoustic performance and fire rating level (FRL) without the need for adding an additional layer of fire‑grade plasterboard or increasing the thickness of the CLT substrate.”
Dunn said the research will be presented in full at Timber Construct, Australia’s only dedicated timber‑in‑construction conference. “Dr Louis Wallis, the deputy director at the University of Tasmania’s Centre for Sustainable Architecture with Wood, will chair a panel that will include Jeremy Church and Andy Russell, from Proctor Australia/DTech, during a session that will also look at point‑supported mass timber building systems,” Dunn said. “As one of just three mass timber and timber frame‑focused industry conferences, our primary focus is on commercial‑ready applications of timber technology. We focus on materials, design, prefabrication and building techniques.”
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