Search results for: roofs

<p>BRANZ reviewed the current building regulations for managing fire spread from roofs to adjacent taller buildings and compared them with the regulations in five other countries.</p><p></p><p>Read the <a id="299" linktype="page">full report</a></p>

<p>The interstitial moisture (condensation within the building structure) stream looked at moisture management in roof spaces - both residential and commercial.</p>

<p>Inspections carried out on roofs have identified a range of potential issues. Problems can often be traced to design issues, installation issues or owner and maintenance issues among others.</p>

<p>There is no specific method for calculating the thermal impact of fires from roofs in New Zealand Building Code Verification Method C/VM2 or in the scientific literature. BRANZ investigated adapting related published research and modelling approaches for this purpose, validated by limited small-scale experimental fires.</p><p></p><p>Read the <a id="299" linktype="page">full report</a></p>

<p>There has been an increasing number of reports of excessive condensation within the roofs of institutional buildings in New Zealand over the last few years. These roofs have a common similar design entailing large roof cavities, profiled metal roofs with underlay, metal framing, batt insulation on the ceiling and acoustic tile suspended ceilings.</p><p>Some condensation was appearing under the metal roofs, but these roofs are designed to tolerate this occurrence and so was not the problem condensation mechanism. Rather, unexpectedly, condensation controlled by a continuous underlay was collected on the metal structural elements, in particular, the roofs&#x27; metal purlins.</p><p>An understanding of this condensation mechanism and how to avoid it is the subject of this report.</p>

<p>In skillion roofs, the roof cladding and ceiling run parallel, typically within 300 mm of each other. The roof space is generally inaccessible, with little natural ventilation, and the small roof space can accelerate problems with moisture. Skillion roofs need carefully designed and installed ventilation to reduce the risk of moisture-related problems.</p>

<p>This is the final report of research into fire spread from lower roofs. This project is part of the larger BRANZ medium-density housing (MDH) research programme.</p><p>As New Zealand building densities increase, the potential for external fire spread and the impact of associated building regulations also increases. In particular, the recent push for higher-density housing results in more situations where external fire spread regulations are relevant. One such requirement is the ‘9 or 5’ fire spread from lower roofs rule in the New Zealand Building Code clause C1–6 Protection from fire Acceptable Solutions and Verification Method. The justification for this rule has not been made clear. The influence of this rule on fire risk, which requires fire protection of either the wall adjacent to a lower roof (up to 9 m vertically above the roof) or the roof (up to 5 m horizontally from the wall) is not well quantified.</p><p>This study report investigates requirements in other jurisdictions and existing research literature and provides comparisons with the current New Zealand regulations. The specific fire spread from lower roofs requirement in New Zealand does appear to be more conservative when compared to Australia, Canada, the US, the UK and Sweden. However, the general wall and roof requirements in other jurisdictions can override the specific requirements in some configurations and provide a similar or greater level of safety for this scenario. Potential heat fluxes on an adjacent external wall are estimated using flame height data and correlations and flame radiation models, and a series of reduced-scale experiments were conducted, with both categories of data compared to the prescriptive requirements.</p><p></p><p>See the <a id="2391" linktype="page">BRANZ Research Now</a> for a short and accessible summary of this report</p>

<p data-block-key="487no">Strandsarking is an engineered woodpanel sheet material treated to Hazard Class H3.1 for use as a roof sarking under membrane roofs.</p>

<p>Strandsarking® is an engineered wood-based panel material for use as a roof substrate under membrane roofs. All panels are ink marked with the New Zealand Timber Preservation Council registration number and treatment type, Strandsarking and a five-digit traceability code. </p>

In this issue: A tale of two timbers (H3.1 and H3.2), Notching and boring, The importance of underlay with metal roofs