Fires in cavities in residential buildings: the performance of cavity barriers in external walls with combustible materials

Guidance for designers, builders and building control on installation and inspection of cavity barriers

In recent times there has been significant interest, scrutiny and debate from stakeholders about the risk of fires in timber-framed buildings, with one particular area of concern being the unseen spread of fire within wall cavities and roof voids. This report describes findings from 21 fire experiments which evaluated fire spread in cavities where sheathing materials were included on the structural side. The work showed that properly fitted cavity closers were effective at inhibiting the spread of fire, but that any discontinuities in cavity barriers had a significant adverse effect on performance. The report provides guidance for designers, builders and building control on best practice in the installation and inspection of cavity barriers.